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This is a continuation of application Ser. No. 08/002449 filed on 08 JAN. 1993, now abandoned, which is a continuation in part of application Ser. No. 07/660,202 filed 25 FEB. 1991, now U.S. Pat. No. 5,195,571 issued 23 MAR. 1993.
CROSS-REFERENCE TO RELATED APPLICATION
This application is related to application Ser. No. 07/660,202, filed Feb. 25, 1991.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method of die cast molding a metal directly onto a fiber reinforced plastic body to form a structure. In particular, a structure formed pursuant to this method includes a preselected failure site to control separation of the cast metal from the plastic body when the structure is subjected to excessive tensile loads.
2. Description of the Related Art
Links, generally formed as elongated metallic members having eyelets on each end, are well-known in the automotive industry. In particular, links are used to connect various components in a suspension system. In use, a link can be subject to compressive, tensile and shear loads.
It is desirable to substitute lighter materials for traditional metals such as aluminum to form links. Fiber reinforced plastic, typically referred to as FRP, may find increasing usage in the automotive industry, despite its higher cost, because of its high strength to weight ratios. However, one problem with substituting FRP for metal in any automotive component is the fact that it is difficult or impossible to form it into shapes that are convoluted or discontinuous. Thus, it may serve well as a drive shaft, which is an elongated tube of constant cross section, but not as a transmission case, with its labyrinthine internal passages.
Another limitation is that many automotive components must be attached directly to another metal component at some point, which may require that the FRP component be provided with a localized metal fastening member. For example, an FRP drive shaft must have a metal connector at each end for attachment to the remainder of the drive line. It is difficult to successfully and securely mate FRP directly to metal, especially when the attachment point will be subject to heavy loading and stress. Many patents are directed just to the problem of joining metal end pieces to FRP drive shafts, most of which involve various adhesives, rivets, splines or combinations thereof.
The designer of an FRP link would face both problems noted above. The main body of a link is basically a rod or beam with a fairly constant cross section and smooth exterior surface, presenting no particular protrusions or discontinuities. This is a basic shape that would lend itself well to FRP manufacture. A matrix of full length reinforcing glass fibers soaked with a conventional thermosetting resin is formed in a mold with the desired beam shape, and then heat cured. However, each end of the beam must be connected to other structures, e.g., between a suspension support and a wheel assembly support. Die casting a metal eyelet directly to the end of an FRP beam would be preferable, in terms of time, cost and strength, to attaching a separate connector by adhesive or mechanical means. However, the thermoset resin that binds the fibers together decomposes badly at the melting temperatures of suitable metals, such as aluminum alloy. Tests that subjected FRP to molten metal for times comparable to the cycle times involved in standard die casting operations found such severe thermal decomposition of the resin as to conclude that the process would not be feasible.
A particular aspect of a joint between an FRP body and a metal must be addressed when the component is subject to tensile loads. Under excessive tensile loads, the metal may completely pull away from the FRP member. If the component is a link, e.g., a FRP rod connected to a metal eyelet, complete separation of the eyelet from the rod under excessive tensile loads is unsatisfactory.
SUMMARY OF THE INVENTION
The present invention includes a method for making a structure in which metal is die cast directly onto a fiber reinforced plastic body. Thermal alteration of the binding resin results in a bonding interface between the FRP body and metal. Furthermore, the structure is formed so that if excessive tensile loads are incurred, a preselected failure will occur in the metal prior to the complete separation of the metal from the FRP body. This preselected failure provides a safety factor in load-carrying applications such as links since the bonding interface between a portion of the metal continues to resist separation from the FRP body.
The present invention includes a method for manufacturing a structural component including the step of forming a groove in an outer surface of a fiber reinforced body. Molten metal is introduced to an exposed surface of the groove and to a predetermined portion of the outer surface of the body. The metal is cooled in a controlled manner to thermally alter sufficient resin to create a secure interconnection of the metal on the body. The metal adjacent the groove is sized so that it will fail prior to separation of the metal from the body under excessive tensile loads. A portion of the metal remains on the body so that elongation of the component significantly exceeds ultimate elongation of the fiber reinforced body and the cast metal.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a molding apparatus illustrating a pair of larger master dies designed to contain a pair of smaller unit dies, which are removed for ease of illustration.
FIG. 2 is a perspective view of a shot chamber that feeds a charge of molten metal into the molding apparatus of FIG. 1.
FIG. 3 is plan view of one of the unit dies designed for the master dies of FIG. 1, illustrating a cavity machined therein.
FIG. 4 is a sectional view of two unit dies spaced apart, illustrating the plane in which they part.
FIG. 5 is a perspective view of a FRP body.
FIG. 6 is a sectional view of the FRP body taken along the line 6--6 of FIG. 5.
FIG. 7 is a sectional view of the two unit dies closed together with the FRP body supported between them and extending into the mated cavities.
FIG. 8 is a sectional view taken through the unit dies of FIG. 7 after injection of metal around the end of the FRP body and schematically showing the heat flow therefrom.
FIG. 9 is a plan view of the completed part, showing a flow of melted resin that has squeezed out of the FRP-metal interface.
FIG. 10 is a sectional view taken along the line 10-10 of FIG. 9, showing schematically the interlock of the metal with the fibers exposed at the surface of the FRP body.
FIG. 11 is an actual photomicrograph taken with a scanning electron microscope at approximately 250X magnification, showing an enlarged circled portion of the interface of FIG. 10.
FIG. 12 is a perspective view of a link having a FRP rod and a pair of opposite eyelets, each eyelet having a neck receiving the rod.
FIG. 13 is a sectional view through the left eyelet and a portion of the FRP rod of FIG. 12 without sectional cross-hatching illustrating tensile and shear stresses occurring during tensile loading of the link.
FIG. 14 is a view similar to FIG. 13 illustrating the fracture of the neck due to extreme tensile loading and the retention of the rod in the remaining neck portion.
FIG. 15 is a perspective view of a vehicular suspension system illustrating the link of FIG. 12 connecting a knuckle and spindle assembly to a suspension cradle.
FIG. 16 is a graph schematically illustrating the elongation of the link of FIGS. 12-15, marked to indicate the fracture of the neck at X A and the separation of the rod from an outer portion of the neck at X B .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A molding apparatus for use with the present invention is illustrated as a cold chamber die casting machine indicated generally at 10 in FIG. 1. Machine 10 is of the type that has two main halves, called die holders or master dies 12. The master dies 12 are the foundation of the apparatus, supporting such features as cooling water lines 14, a sprue spreader 16, and leader pins 18. A shot chamber 20 and plunger 22, illustrated best in FIG. 2, which are used to send a charge of molten metal 24 into the machine 10 are supported on the master die 12 opposite the sprue spreader 16. Detailed information about metal 24 is presented below. The master dies 12 support a pair of smaller unit dies, indicated generally at 26 and 28. It is the unit dies 26 and 28 that actually form the molded shape desired, allowing machine 10 to be used to make several different components.
Each unit die 26 and 28 is a steel block, measuring nine by three by five inches, and therefore provides a significant heat sink mass in and of itself. Furthermore, each unit die 26 and 28 makes intimate surface to surface contact with the interior of the master die 12 that supports it, thereby providing additional heat sink mass. Each unit die 26 and 28 has a matching cavity 30 (FIGS. 3 and 4) machined therein, the basic dimensions of which, X 1 through X 7 in inches, are 1.25, 1.0, 2.0, 0.75, 4.25, 0.125, and 0.25 respectively. An enlarged end is formed in each cavity 30. Unit die 28 has a pair of locator pins 32 in its cavity 30 as well as a cooling water passage 34, but is identical to unit die 26 otherwise. In use, the unit dies 26 and 28 would be vertically opposed to one another, but are shown horizontal in FIG. 4 for ease of illustration. While machine 10 as disclosed is basically conventional, it should be understood that it would normally be used simply to cast a solid part of metal only.
One of the two constituents of the structural component produced by the method of the present invention is a compression molded FRP body, indicated generally at 36 in FIGS. 5 and 6. Body 36 is a short beam of constant rectangular cross section, with a six inch length, one inch width, and a quarter inch thickness. It is manufactured by first laying up a matrix of full-length glass reinforcing fibers 38 lengthwise within a mold that has the same shape as body 36. The content of fibers 38 is about 72% by weight. Then, a thermo-setting resin 40, which in this case is an amine cured bisphenol-A epoxy system, is injected around the bundle of fibers 38. The composite is then heat cured under pressure in the mold at 250 degrees F. for approximately ten minutes, and post cured out of the mold at 310 degrees F. for about fifteen minutes. Finally, a pair of holes 42 are drilled to match the locator pins 32 of unit die 28.
The temperature sensitivity and responsiveness of the fibers 38 and resin 40 as compared to metal 24 is important. Metal 24 is a standard 380 aluminum alloy, which is commonly used in die casting, and which has a melting point of 1220 degrees F. While the glass fibers 38 can withstand such a high temperature, this temperature is substantially beyond the temperature that the resin 40 could be expected to withstand without suffering very significant decomposition, even to the point of total structural failure of the part. In fact, tests showed that a sample like body 36, when dipped into molten aluminum for a time comparable to a normal molding cycle timer did suffer debilitating thermal decomposition. Thus, it was expected that an untreated, unprotected part like body 36 would never survive having aluminum die cast to it. Nevertheless, a method for doing so was developed and is described next.
The basic steps of the present die cast molding method are illustrated in FIGS. 7 and 2. First, body 36 is supported by inserting locator pins 32 though holes 42. Then, the unit dies 26 and 28 are closed. While most of the length of body 36 is closely contacted and pinched off by the inner surfaces of the cavities 30, an end of body 36 extends freely into the enlarged ends of the mated cavity 30. An unobstructed volume or chamber is thereby created that completely surrounds the end of body 36. The interior surfaces of the enlarged ends of the mated cavities 30 are close to the exterior surface of the end of body 36, so the surrounding chamber they create is symmetrical, with a basic thickness of one eighth of an inch, as measured perpendicular to the surface of body 36. Next, a charge of molten metal 24 is forcibly pushed in from shot chamber 20 by plunger 22, and fills the chamber around the end of body 36 completely in less than a tenth of a second. Non-illustrated vents and wells in the unit dies 26 and 28 are provided to accommodate the displaced air as the molten metal 24 enters under pressure.
As seen in FIG. 8, an inner jacket or envelope is established at the interface of metal 24 with the external surfaces of body 36, and a surrounding outer jacket or envelope at the interface between metal 24 and the inner surfaces of the cavities 30. A relatively rapid outer heat flow from metal 24 to the unit dies 26 and 28 is immediately established at the outer envelope, which is visually represented by the longer arrows. The radially outward heat flow from metal 24 results from the large heat sink mass of the unit dies 26 and 28 and the master dies 12, an effect that is aided by the circulation of cooling water through water lines 14 and water passage 34. Water is pumped through at a flow rate of approximately 20 gallons a minute. Heat flow from metal 24 is also kept rapid and even by the relative thinness of the filled volume around the end of body 36, and by the symmetry of the volume described above. The unit dies 26 and 28 are kept closed for about ten seconds, after which time the metal 24 cools to about 500 degrees F and solidifies. The steady state operation temperature of the unit dies 26 and 28 has been measured to be about 350 degrees F.
The end product is illustrated in FIG. 9. After ten seconds, the unit dies 26 and 28 are opened and the completed part, consisting of body 36 and now solidified metal end member 44, is ejected and water cooled to room temperature. After removal, a black substance is sometimes observed to ooze out and solidify in a small, shiny pool indicated at 46 at the joint between the surface of body 36 and metal member 44, which is further explained below. Clearly, the body 36 has not decomposed or burned to the point where it has eaten through or fallen off, but its response to heavy loading is more important to proof of production feasibility. In fact, the completed part is not used as an actual component, but as a tensile test specimen to indicate that feasibility. It is held by the holes 42 in a test machine and a measured pulling force applied to metal member 44. Tensile loads of approximately 1400 pounds have been achieved. Since a component like a wiper arm would have a body shaped much like body 36 and a metal end connection member similar to member 44, which could be later drilled, machined, splined or otherwise shaped. This is impressive evidence of production worth. Two phenomenon are thought to contribute to the success of the process and the strength metal to body bond. One is clearly the rapid and even cooling of the molten metal 24, which protects the body 36 from excessive damage. Even more important, however, is what happens at the inner envelope, described next.
The action at the interface between molten metal 24 and the exterior surface of the end of body 36 is illustrated in FIGS. 8-11. The heat flow out of molten metal 24 is not so rapid that no heat flows radially inwardly therefrom to the surface of body 36. Instead, a radial inward heat flow to the surface of body 36 is established, represented by the shorter arrows in FIG. 8. Just as with the outward heat flow, the rate is kept relatively even by the symmetry of the surrounding volume. While the temperature at the metal-FRP surface interface has not been directly measured, it has been observed from laboratory tests that resin like resin 40 begins to decompose at between seven and eight hundred degrees F. It appears that the temperature at the surface of body 36 must approach that temperature, because it is clear from two observed phenomenon that some of the resin 40 at the upper surface layer of body 36 does decompose, a phenomenon represented by the phantom line in FIG. 10. One observation is the solidified outflow 46. This is clearly melted or otherwise liquefied resin 40, at least in part, since it is not metal and the glass fibers 38 will not melt even at the melting temperature of the metal 24. More telling is what is observed by cutting, polishing and observing the interface under magnification, as seen in FIGS. 10 and 11. The resin 40 has clearly degraded over a layer varying from about 30 to 70 micrometers in thickness, exposing some of the fibers 38. The metal 24 has clearly flowed amongst and around the exposed fibers 38, creating a secure interlock and interconnection therewith.
While it is clear that it does occur in fact, the exact mechanism of the thermal degradation of resin 40 is not exactly understood. It apparently gasifies, and in some cases at least, condenses and liquefies again, witness pool 46. Clearly, the decomposition process is limited in effect and depth, as it does not structurally threaten the part. An important factor in the control and limitation of the level of thermal decomposition is the rapid and even cooling of the metal 24 so that not too much resin 40 is lost. Another controlling and limiting factor may well be the exposed layers of fibers 38 themselves acting as insulation against the heat, and the fiber content of body 36 is relatively high. Other control factors may be the exclusion of air by the close fill of the molten metal 24, or the pressure that it is under. It is very significant that the thermal decomposition process is limited and controlled, by whatever mechanism, as opposed to being prevented altogether. A logical approach, knowing that the molten metal 24 was far hotter than necessary to induce rapid thermal decomposition of the resin 40, would be to try to prevent it from occurring at all, or at least substantially, by more rapid cooling, or by deliberate heat insulation and protection of the outer surface of body 36 over that portion to be contacted by molten metal 24. In fact, this was tried with various thermal barrier materials, such as stainless steel flakes and silica, which were also test cast with a metal having a lower melting temperature. While thermal loss of resin was substantially prevented, the metal to FRP surface joint was not nearly so strong.
Variations of the process should be possible within the basic outlines disclosed. Most broadly conceived, the idea is to introduce molten metal directly to the surface of the FRP part, and then cooling and time limiting its contact sufficiently to expose a top layer of reinforcing fibers around which molten metal may flow and interlock with. As disclosed, the molten metal is introduced in surrounding relation to an external surface of an FRP part, but it could conceivably be poured directly into a concavity in the part, with no mold, and cooled by some other means. More could be done to tailor the characteristics of the FRP fibers and resin to the molten metal and vice versa so as to achieve the desired result, such as increasing the fiber content at the surface, or experimenting with different metals, temperatures, or even surface coatings that provide some, but not a complete, thermal barrier. For example, it is thought that the shrinkage of the cooling aluminum around the end of body 36 aids in creating the bond. Other metals might shrink even tighter. Each designer will undoubtedly experiment with different cooling rates, metal thicknesses and cycle times so as to achieve the optimum level of the resin degradation and metal interlock that has been discovered here. While the symmetry of the chamber surrounding the end of body 36 aids in even cooling, asymmetric shapes could be molded, as well. Judicious placement of cooling lines could be used to control the cooling rate. Therefore, it will be understood that it is not intended to limit the invention to just the embodiment disclosed.
While body 36 was designed as a tensile test specimen, an automotive link formed according to the die cast molding method described above is indicated generally at 100 in FIG. 12. The link 100 can be designed for compressive and tensile loading, and can be adapted for a variety of applications, including between a knuckle and spindle assembly 122 and a cradle 124 in a vehicular suspension system 120 illustrated in FIG. 15. Such a suspension link 100 is a load bearing member subjected to alternating tensile and compressive forces during operation of a vehicle. Various elastomeric bushings (not illustrated) and fasteners (not illustrated) can be used to secure each end of the link 100 to a desired support.
The completed part, i.e., the link 100, includes an elongated rod 102. The rod 102 is a FRP body made with full-length glass reinforcing fibers 101 in a thermo-setting resin 103. The rod 102 is preferably formed by a pultrusion process. In this process, continuous fibers 101 are pulled into a resin wet out bath where the fibers 101 are saturated with liquid resin 103. Then, the fibers 101 are drawn from the bath through a squeeze out die, which controls the fiber/resin ratio, and into a heated final forming die where the thermo-setting resin 100 hardens and cures. The solid composite is pulled out of the final forming die by in-line pulling units which grip the composite and work in tandem to pull material through the entire process continuously. A flying cut-off unit cuts the composite into predetermined lengths.
A circumferential groove 104 is provided at a predetermined depth and width near each end portion of the rod 102. Preferably, the rod 102 has a smooth, continuous outer circumference and the groove 102 is a uniform channel cut in the circumference. However, other rod cross sections and groove configurations are within the scope of the invention.
A casting is formed as an eyelet 106 in unit dies similar to unit dies 26 and 28, wherein the unit dies have suitably formed cavities. Each eyelet 106 includes a neck 108 to accept a predetermined length of the rod 102. Each groove 104 is cut in the rod 102 so that the neck 108 extends past the groove 104 a predetermined distance. Webs 110 can be provided on the outer surfaces of the eyelet 106 and neck 108 to strengthen the casting.
Molten metal 24, such as a standard 380 aluminum alloy, is introduced to unit dies supporting the rod 102 according to the die cast molding method disclosed above. As the molten metal 24 solidifies, an annular projection 114 is formed in the inner diameter of the neck 108 which extends radially inwardly to completely fill the groove 104. The resin 103 at the outer circumference of the rod 102 and the exposed surface of the groove 104 undergoes thermal alteration and exposes glass fibers 101. As described above, even cooling of the molten metal 24 protects the rod 102 from excessive damage. The joint formed between the projection 114 and the groove 104 and between the rod 102 and the neck 108 is referred to as the interlocking region.
FIG. 13 schematically illustrates tensile loading in the link 100. The tensile load in the eyelet 106 is indicated by arrows 116 and the tensile load in the rod is indicated by arrows 118. This tensile loading produces mechanical stresses in five locations within the link 100. Bending stresses present in eyelet 106 are illustrated at 120. Tensile stresses in the neck 108 are illustrated at 122. Tensile stresses in the rod 102 are illustrated at 128. Shear stresses 126 are present in the portion of the rod 102 from the annular projection 114 to the end of the rod 102. Shear stresses 124 are present in the annular projection 114.
Stress in any material causes the material to elongate. If the elongation exceeds the ultimate elongation of the material, the material will begin to crack and fail. Both materials used to fabricate the link 100 have a low ultimate elongation and are brittle materials. The aluminum at eyelet 106, neck 108, and annular projection 114 has an ultimate elongation of 3%. The FRP in the composite rod 102 has an ultimate elongation of 2.5% A brittle material tends to fail very rapidly after a crack forms.
It would be expected that if the stress at any one of the five locations within the link 100 caused the respective ultimate elongation to be exceeded, the respective material would crack and rapid failure would result. However, failure at a selected site of the five locations does not exhibit a rapid, brittle failure. The present design is intended to create failure at this selected location during extreme tensile loading of the link 100.
The location in the link 100 which does not exhibit a rapid, brittle failure during extreme tensile loading is the portion of the neck 108 adjacent the annular groove 104. At this location tensile stress 122 and shearing stress 124 are present in the aluminum. In addition the sharp corner of the annular groove 104 creates a stress concentration factor which amplifies stresses 122 and 124. Thus, the portion of the neck 108 adjacent the annular projection 114 is made weaker than the eyelet 106, the rod 102 in a tensile mode, and the rod in a shear mode.
Under high tensile loading, a crack 130 develops in an inner surface of the neck 108 adjacent projection 114 and propagates to the outer surface of the neck 108, eventually causing an inner portion 108A of the neck 108 to break away from an outer portion 108B of the neck 108 as illustrated in FIG. 14. However, the fracture of the neck 108 does not result in immediate separation of the rod 102 from portion 108B. As schematically illustrated in FIG. 16, tensile loading of the link 100 increases to F A , at which point the neck 108 fractures into portions 108A and 108B after an elongation of X A . Subsequently, a varying force is required to pull the rod 102 from the outer neck portion 108B for a total elongation of X B . As the rod 102 pulls away from the outer portion 108B of the neck 108, a chamber 132 is formed.
A significant amount of energy is required to completely separate the eyelet 106 from the rod 102. This is due to the penetration of the alloy into the composite as described above. Testing has shown the amount of elongation of the link 100 is much greater than the ultimate elongation of the materials it is made from. The ultimate elongation of the aluminum is 3% and the ultimate elongation of the FRP is 2.5%. As shown in FIG. 16, the link 100 undergoes significant elongation prior to separation. For example, the original length of a tested link was 330 mm. Separation of the rod from the outer neck portion occurred at 52 mm, resulting in an elongation of approximately 16%.
The above disclosed interlocking joint provides a controllable failure mode in the event of extreme tensile loading. The neck 108, groove 104, and projection 114 can be varied as desired to provide a selected load at which failure begins to occur. The length of the rod 102 behind annular projection 114 can be varied to provide a selected amount of ultimate elongation of link 100. The length of the rod 102 behind annular projection 114 can be varied to provide a selected amount of energy to separate the portion of the casting 106 and 108B completely from the rod 102.
Although the present invention has been described with reference to preferred embodiments, workers 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.
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A method for manufacturing a structural component includes forming a groove in an outer surface of a fiber reinforced body. Molten metal is introduced to an exposed surface of the groove and to a predetermined portion of the outer surface of the body. The metal is cooled in a controlled manner to thermally alter sufficient resin to create a secure interconnection of the metal on the body. The metal adjacent the groove is sized so that it will fail prior to separation of the metal from the body under excessive tensile loads. A portion of the metal remains on the body so that elongation of the component significantly exceeds ultimate elongation of the fiber reinforced body and the cast metal.
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This application is entitled to the benefit of Provisional Patent Application Ser. No. 60/339,586 filed Dec. 11, 2001.
FEDERALLY SPONSORED RESEARCH
Not Applicable
SEQUENCE LISTING OR PROGRAM
Not Applicable
BACKGROUND—FIELD OF INVENTION
This invention relates to a chiller plant, and specifically methods of operation that will reduce the power usage and improve the plants efficiency.
BACKGROUND—DISCUSSION OF PRIOR ART
A chiller plant as shown in FIG. 1, includes a chiller ( 5 ), a cooling fluid pump ( 1 ), a cooling tower ( 3 ), and a cooling fluid piping circuit ( 11 ) which interconnects these pieces of equipment. The chiller plant produces a chilled fluid that is distributed in a chilled fluid piping circuit ( 12 ).
The chiller plant may also include a plurality of chillers, pumps, and cooling towers. For instance multiple chillers can be operated in parallel, with a single cooling fluid piping circuit connecting all chillers to the same cooling tower. Another system shown in FIG. 2 has a separate fluid cooling circuit, and separate cooling tower for each individual chiller in the chiller plant.
The chiller ( 5 ) is a refrigeration machine that chills water or other fluid mediums to a controlled temperature level. It is a complete unit consisting of a refrigerant condenser ( 4 ), a refrigerant evaporator ( 10 ), a refrigerant compressor ( 9 ), a chiller control panel ( 8 ), and an electric motor drive ( 7 ). The chiller ( 5 ) is typically provided as a single package by one manufacturer. The cooling tower ( 3 ), cooling fluid pump ( 1 ), and cooling fluid piping circuit ( 11 ) constitutes a heat rejection system for the chiller plant. The cooling tower ( 3 ) can have one fan ( 6 ) or a plurality of fans. The cooling tower ( 3 ) fans ( 6 ) and the cooling fluid pump ( 1 ) have electric motor drives ( 7 ). The electric motor drives ( 7 ) may be constant speed or variable speed.
The Cooling fluid pump ( 1 ) forces a cooling fluid ( 2 ) to circulate from the cooling tower ( 3 ) to the refrigerant condenser ( 4 ) of the chiller ( 5 ) and back to the cooling tower ( 3 ). When chiller ( 5 ) is operating pump ( 1 ) operates at a constant flow rate. Fan ( 6 ) for cooling tower ( 5 ) also operates independently of the chiller.
The chiller, the cooling tower fan, and the cooling fluid pump all have control systems that are independent of each other. During periods of operation, when the chiller is operating at part load, the cooling tower fan, and the cooling fluid pump will be operating at full or a high and unnecessary power setting, thus wasting a substantial amount of energy. Since the chiller typically operates at part load for most of the time, the amount of wasted energy over time can be quite large.
The chilled fluid temperature is controlled by the chiller to a set temperature. The chiller set point can be adjusted by the chiller plant operator, either manually, or through an automatic control system provided for the plant. When loading levels on the plant are low, it can be desirable to reset the chilled fluid temperature to a higher level to reduce energy usage.
Various control systems have been applied in the past, which have automated portions of the chiller plant and it's heat rejection system. The automation was initially designed to eliminate manual control, then additional automation for better control and to save energy, which quickly becomes obsoleted with the availability of better instrumentation and computerized controllers.
FIG. 2 shows a chiller plant with a plurality of chillers, pumps and cooling towers. This depicts a method for controlling cooling fluid pumps, cooling tower fans, and chiller operations in a coordinated fashion to reduce energy usage.
A computerized controller ( 13 ) controls the speed of the electric motor drives ( 7 ) for the cooling tower fan ( 6 ), the cooling fluid pump ( 1 ), and chiller ( 5 ).
U.S. Pat. No. 6,257,007 to Hartman (2001), and U.S. Pat. No. 6,185,946 to Hartman (2001) describe methods similar to FIG. 2, where the system components of the chiller plant are controlled in response to the current loading level on the cooling system. The current loading level is always determined by specific chiller parameters such as power, or refrigerant head pressure, or motor speed. Therefore, these methods may require direct access to the selected chiller parameters. Since the chiller manufacturer normally does not provide for this type of access, it can only be implemented with the special help from the manufacturer.
U.S. Pat. No. 5,963,458 to Cascia (1999) describes a generic computer designed to use chiller load data derived from the chiller plus additional parameters that include wet bulb temperature, tower air flow rate, and condenser water flow rate. The computer then determines the optimal set point for operation of cooling tower fans, condenser water pumps, and chillers. The computer can be set up to provide set point operation to as many or as few components as desired. The electric motor drives can be either variable speed or constant speed. A large number of peripheral devices are required and the control sequence can only be implemented through this generic computer with a set of complicated and difficult to understand control algorithms. It can only be implemented with the help of highly trained specialists.
Another method for the control of the cooling fluid pump is disclosed in U.S. Pat. No. 5,070,704 to Conroy. A plurality of chillers are served by one cooling fluid pump. The chillers each have control valves which shut off cooling fluid flow when that chiller is off line. The cooling fluid pump has a variable speed electric motor which is controlled by way of a pressure sensor located in the cooling fluid circuit. This control has limited application in today's chiller plant that typically has separate pumps matched to each chiller.
A number of methods have been disclosed for the control of cooling tower fans. U.S. Pat. No. 4,085,594 to Mayer, (1978) controls fans in response to the temperature of the cooling fluid, as is also shown in and U.S. Pat. No. 4,252,751 to Shito, (1981). The principle intention was to automate the cooling tower control and eliminate man power. More efficient controls were introduced with U.S. Pat. No. 4,474,027 to Kaya, et al, (1984), which discloses the use of wet bulb temperature to optimize the speed of the cooling tower fans. Additional improvements in energy usage are introduced in U.S. Pat. No. 5,040,377 to Braun et al, (1991) and U.S. Pat. No. 5,600,960 to Schwedler et al, (1997), both include a means to determine the chiller load by measuring the temperature and flow rate of chilled fluid that enters and exits the evaporator, as well as a means for determining wet bulb temperature and cooling fluid temperature, then control the cooling tower fan to the desired speed. Multiple input parameters are required, which must be compared using multiple logic loops to finally determine the desired control output, making a complicated control regime, requiring highly trained specialists to implement.
Object and Advantages
Several objects and advantages of the present invention are:
(a) to provide method to maintain a constant, or near constant, temperature difference of the cooling fluid as it enters and exits the refrigerant condenser.
(b) to provide a method to control the flow rate of the cooling fluid to the refrigerant condenser.
(c) to provide a simple method to control the cooling tower fan speed based on the cooling fluid temperatures and cooling fluid flow rate.
(d) to provide a simple method to allow sequencing of a plurality chillers, and optimize combined energy efficiency of the operating chillers.
(e) to provide a method of control for condenser water pumps, and cooling tower fans of a chiller plant that has a constant speed chillers and variable speed chillers in the same plant.
(f) to provide a method of control that is simple to install and maintain.
(g) to provide a method of control that is flexible and adaptable to different chiller plant designs.
(h) to provide a method of control that does not require direct access to proprietary wiring and controls of a manufacturer's chiller.
(i) to provide a method of control that can be retrofitted to existing chiller plants.
Further objects and advantages are to provide a simple method of control that uses off the shelf components, can be provided as a stand-alone system without the support of a building automation system, can also be incorporated into major building automation systems, is flexible in the inclusion or exclusion of controlled components, does not require proprietary knowledge of chiller manufacturer's equipment, can be easily employed by the engineering and construction disciplines. Still further objects and advantages will become evident from a consideration of the ensuing description and drawings.
SUMMARY
In accordance with the present invention it provides a methodology for the control of chiller plants that will improve the combined system efficiency of the various pieces of equipment to improve the overall energy usage.
DRAWINGS
Drawing Figures
In the drawings, equipment components with the same equal function using the same equipment have the same number through out. Closely related components with similar functions will have the same number but different alphabetic suffixes.
FIG. 1 shows prior art which is a typical chiller plant installation where the chiller, cooling tower, and fluid cooling pump operate independently.
FIG. 2 shows prior art with a plurality of chillers and equipment that have controls to coordinate the operation of all the equipment.
FIG. 3 shows the main embodiment of the invention that manages and controls the operation of cooling tower fans, cooling fluid pumps and sequences chillers in a multi-chiller plant.
FIG. 4 shows a similar but simpler invention that controls the operation of cooling tower fans and cooling fluid pumps.
FIG. 5 shows a similar but even simpler invention that controls the operation of only the cooling fluid pump.
REFERENCE NUMERALS
1 cooling fluid pump
2 cooling fluid
cooling tower
3 refrigerant condenser
4 chiller
5 fan
6 electric motor drive
7 chiller control panel
8 refrigerant compressor
9 refrigerant evaporator
10 cooling fluid piping circuit
11 chilled fluid piping circuit
12 computerized controller
13 temperature sensor
20 flow meter
22 temperature controller
23 instrument receiver
24 differential temperature transmitter
25 a computerized controller with analog inputs, and outputs
25 b computerized controller with added functionality
DESCRIPTION
Description—FIG. 3 —Preferred Embodiment
The preferred embodiment of the, present invention is illustrated in FIG. 3. A chiller plant with a plurality of chillers, cooling fluid pumps and cooling towers with fans and a control system that manages the overall operation of the chiller plant to achieve the lowest energy usage and highest energy savings.
A matched pair of temperature sensors ( 20 ) are installed in the cooling fluid piping circuit ( 11 ) such that the entering cooling fluid temperature and the leaving cooling fluid temperature at the refrigerant condenser ( 4 ) are accurately measured. A flow meter ( 21 ) is installed in the cooling fluid piping so that it measures the flow rate thru the refrigerant condenser.
A BTU meter ( 23 ) receives the temperature signals from each temperature sensor ( 20 ) and the flow rate signal from the flow meter ( 21 ). An instrument receiver calculates the temperature difference, and if wanted BTU rate. The temperature difference signal, a BTU rate signal, fluid flow rate signal, and entering and leaving cooling fluid temperature signal made available to a computerized controller ( 25 a ).
The computerized controller ( 25 a ) will maintain the temperature difference, between the the entering cooling fluid temperature and the leaving cooling fluid temperature at the refrigerant condenser, to a constant value. This value, used as a set point, is typically the design temperature difference originally established by the chiller ( 5 ) manufacturer's design specification. The computerized controller ( 25 a ) compares the temperature difference signal to the set point temperature difference. Control output signals are then generated and sent to the variable speed electric motor ( 7 ) for the cooling fluid pump ( 1 ). The speed of the cooling fluid pump ( 1 ) is controlled to maintain the temperature difference across the refrigerant condenser ( 4 ). The cooling fluid pump ( 1 ) speed may be controlled directly in response to the temperature difference signal using a conventional “PID loop”. The preferred manner of control for the cooling fluid pump speed will to establish a base flow rate based on design flow rate of the chiller then control to that flow rate with a conventional “PID loop”, using the flow signal input from the flow meter ( 21 ). Then the temperature difference signal will be used to adjust a flow set point upward or downward, based on the selected temperature difference range. The temperature difference control range as an example may have a high temperature of 10 degrees F. and a low temperature of 9.75 degrees F. The flow set point would be adjusted up or down by a fixed increment of flow which is established by the chiller plant's initial design. It is also desired that the flow rate though the condenser not be allowed to fall below a minimum flow rate to prevent fouling of the condenser tubes, and to maintain flow at or above the chiller manufacturer's minimum flow requirements. The computerized controller ( 25 a ) compares a minimum flow rate set point to the said flow rate signal and prevents the flow rate from being reduced below this minimum value, which is easily determined from the manufacturer's published literature.
The computerized controller ( 25 a ) will also control the speed of the cooling tower fan ( 6 ). The entering cooling fluid temperature and the flow rate signal will be evaluated by the computerized controller to determine the appropriate cooling tower fan speed. Control output signals are then generated and sent to the variable speed electric motor ( 7 ) for the cooling tower fan ( 6 ). The temperature of the cooling fluid entering the condenser ( 4 ) is compared to the design cooling fluid temperature for the cooling tower, at the maxim outdoor design conditions. As long as the entering cooling fluid temperature is at or above the design cooling fluid temperature, the cooling tower fan will be maintained at full speed. When the entering temperature of cooling fluid temperature falls below the design cooling fluid temperature by a fixed value, the cooling tower fan speed is then controlled with respect to the cooling fluid flow rate signal provided by flow meter ( 21 ). A fixed relationship will be established, depending on plant design and configuration, to control the fan speed to flow rate signal. An example relationship is Fan Speed %=1.5×Actual Flow Rate %−Constant. Where the constant can be any value between 0 & 50, and the upper limit on Fan Speed is fixed. Also minimum basin temperature values and any condenser water reset values that might ordinarily be designed into a cooling tower system will also be accommodated within the control structure. It is also anticipated that it may be desirable to control the fan speed in multiple steps where the next lower step is only allowed over a selected time period to maintain a more stable system operation.
The set point value for the chilled fluid temperature is a readily accessible input provided by the chiller manufacturer. The computerized controller ( 25 b ) will provide a signal output to adjust the chiller set point. The heat rejection rate of the chiller will be evaluated for each chiller then an appropriate set point value will be generated for that chiller. The BTU rate signal provides the heat rejection rate for each chiller. Using the chiller manufacturers published data and curves for chiller part load efficiency, it is possible to relate the heat rejection rate to the chiller load rate. The chiller plant operator may determine, that a simple formula that allows resetting the chiller set point in direct proportion to the heat rejection rate, be the preferred method of operation. The chiller plant operator may, particularly where there are multiple large chillers involved, use operating curves developed for each chiller to determine the best set point for each operating chiller, where one chiller may have a set point different then the next operating chiller.
FIGS. 4 - 5 Alternative Embodiments
Alternative embodiments are show in FIGS. 4 and 5. The present invention is applicable to the control of cooling fluid pumps and cooling tower fans without coordinating the chiller operation at the same time. FIG. 4 shows that computerized controller ( 25 a ) and its related functions can adequately manage a chiller plant that does not require the full implementation shown in the main embodiment. Another alternative embodiment where the cooling fluid piping circuit ( 11 ) is combined into one circuit for multiple chillers. This variation in chiller plant design would require the addition of a control valve at each refrigerant condenser ( 4 ) for each chiller ( 5 ), which is easily accommodated by this invention.
Furthermore FIG. 5 shows an additional embodiment that will allow application when it is desired to only control the cooling fluid pump. A matched pair of temperature sensors ( 20 ) are installed in the cooling fluid piping circuit ( 11 ) such that the entering cooling fluid temperature and the leaving cooling fluid temperature at the refrigerant condenser ( 4 ) are accurately measured. A differential temperature transmitter ( 24 ) receives the temperature signals from each temperature sensor ( 20 ). The temperature difference signal is sent to a temperature controller ( 22 ) which provides the control output signal for the electric motor drive ( 7 ) of the pump ( 1 ). A low flow limit to protect the refrigerant condenser ( 4 ) will be established with manual balancing during commissioning, then a fixed low limit operating point is programed into the variable speed electric motor drive ( 7 ).
Advantages
From the description above, my method to optimize a chiller plant operation has a number of advantages:
(a). A simple method to control and reduce the pumping energy in the heat rejection circuit of a chiller, with the installation of matched temperature sensors in the fluid cooling loop near the refrigerant condenser, and a basic control circuit for the cooling fluid pump.
(b) Additional control for the cooling tower fan speed is easily combined in a synergistic way to substantially increase energy savings for a small incremental cost in control functionality.
(c) Additional capability to include sequencing and set point adjustment for the operating chillers in a multiple chiller plant provides the plant operator with a flexible method that can be easily customized to any chiller plant operation thus providing additional energy savings.
(d) The method disclosed above can be easily applied to chiller plants where the chillers pumps and cooling towers all vary in size and capacity, and where all of the chillers and pumps and cooling towers share one heat rejection piping circuit.
(e) Many existing chiller plants can be easily retrofitted with this control method.
(f) The engineer, or the contractor can easily install and configure my invention without requiring the intervention of a specialist in computer controls or special knowledge of chiller control or operation.
Conclusions, Ramifications and Scope
The reader can see that the present method is straight forward and uncomplicated. Engineers and technicians with a general knowledge of the art will have no difficulty implementing and incorporating my method, making it more likely that it will be used in a larger number of applications, creating substantial energy savings. The energy savings are significant as a percent of the overall chiller plant energy usage and tend to be synergistic. When a chiller is operating at partial load it does not reject as much heat, reducing the need for cooling fluid. By allowing the flow rate to reduce instead of the temperature difference across the condenser, pump energy is reduced. Also reducing the flow rate improves the performance of the cooling tower, by reducing the cooling fluid temperature, which in turn may improve the efficiency of the chiller. Further reduction in heat rejection load and reducing flow rate, leaves the cooling tower with excess fan capacity that can not be regained to provide additional cooling, therefore reducing the fan speed in a controlled manner will not effect the performance of the cooling tower but, will reduce the energy used by the fan. Much of the energy savings are developed by coordinating the pump and cooling tower operation to the chiller operation. Closer control of chiller operation, changing chilled water temperature set point based on load, will provide some additional energy savings.
While my above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of selected embodiments thereof. Many other variations are possible. For example
the use of an instrument, may be replaced by a transmitter specifically designed for this application.
the temperature difference may be calculated by the computerized controller, in place of an instrument receiver.
the use of a proportional control loop in place of a PID loop to control the variable speed motor drives.
the use of an industry standard “Programmable Logic Controller” in place of the computerized controller.
the use of a “Building Automation System” in place of the computerized controller to provide some or all control functions and outputs described in the above invention.
the use of additional control logic to improve system stability or provide greater energy savings.
the use of differential pressure sensing devices to determine flow rate in place of the flow meter.
Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.
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A chiller plant which produces chilled water for airconditioning, or an industrial process and which is comprised of chillers, cooling fluid pumps, and cooling towers with electrical motor drives uses a substantial amount of energy. A method that coordinates the operation of the cooling tower, cooling fluid pumps, and refrigeration machines so that the chiller plant operates at a higher overall efficiency thus reducing the power usage has been developed and is presented herein. The flow rate of the cooling fluid pumps are controlled to maintain a precise temperature difference across the refrigerant condenser. The cooling tower fans are controlled by comparing the cooling fluid temperature and the cooling fluid flow rate to selected design parameters. The heat rejection rate is measured for each chiller in the chiller plant and operating set points are established for each operating chiller to provide the optimum operation for best energy efficiency.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a computer tomography apparatus of the type which undertakes a helical scan of an examination subject.
2. Description of the Prior Art
It is known in conventional computer tomography systems to produce a conventional x-ray image (shadowgraph) of an examination subject, for the purpose of defining the examination region before beginning the computer tomographic examination. For this purpose, the patient is usually moved through the measurement opening, with the x-ray focus being held at a fixed angular position, and a conventional shadowgraph, i.e., an x-ray projection image, is produced continuously, or pulsed line-by-line. This known technique of obtaining a conventional x-ray image using a computer tomography apparatus has several disadvantages. First, in addition to offering the standard computer tomographic exposure mode with continuous scanning, a further exposure mode must be offered wherein the x-ray focus is held stationary. Additionally, as a result of the creation of two separate exposures, the time required for the complete examination is higher by several minutes compared to the time needed for the actual production of the computer tomogram. Such lengthening of the exposure time is not only economically undesirable, but also the patient frequently changes position between the two exposures, so that a shifting between the selected body region and the body region which is actually registered during the examination can occur.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a computer tomography apparatus and method for operating such an apparatus which permit the simultaneous production of computer tomograms and x-ray shadowgraphs.
The object is achieved in a method for operating a computer tomography apparatus which has a measurement system for continuous (usually helical) scanning of a measurement volume in the direction of a central axis, wherein the computer calculates a shadowgraph of the patient from the tomographic data, the shadowgraph being calculated for a defined projection direction simultaneously with the tomography exposure. The exposure volume can thus be monitored in real time, and the exposure can be stopped when the end point, which can only be radiologically recognized, is reached. All of the data for three-dimensional reproduction of the volume in which the patient is situated are present after a helical scanning of the volume. Computer tomograms and shadowgraphs for arbitrary projection directions can therefore be reconstructed from such data.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an end view of a computer tomography apparatus operable in accordance with the principles of the present invention, with the measurement system being vertically oriented and with certain electronic components being schematically indicated.
FIG. 2 is a side view of the computer tomography apparatus of FIG. 1.
FIGS. 3 and 4 are graphs for explaining the production of x-ray shadowgraphs in the computer tomography apparatus of FIGS. 1 and 2, in accordance with the principles of the present invention.
FIG. 5 is a side view of a further embodiment of a computer tomography apparatus operable in accordance with the principles of the present invention, with the measurement system horizontally oriented.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An x-ray computer tomography apparatus operable in accordance with the principles of the present invention is shown in FIG. 1 having a measurement system 31 which, in FIGS. 1 and 2 is shown oriented vertically. The measurement system 31 has a housing surrounding a measurement field 1, with an x-ray source 2 and an annular anode 3 disposed in the housing. For producing a rotating, fan-shaped x-ray beam 4, the annular anode 3 is scanned by an electron beam 5 which is produced by an electron gun 6. The electron gun 6 is followed by focusing coils 7. A vacuum is maintained in the x-ray source 2 by vacuum pumps 8.
The electron beam is deflected onto the annular anode 3 by a magnetic deflection coil 9 for producing the x-ray beam 4. The x-rays emerging from the examination subject situated in the measurement field 1 are acquired by an annular radiation detector 10, consisting of a series of detector elements 10a. The respective output signals of the detector elements 10a are supplied to a computer 11, which calculates an image of the examined slice of the examination subject from those signals. The image is visually displayed on a monitor 12.
The measurement field 1 is a field in an opening 13 in the housing of the measurement system 31, through which the examination subject is moved. For transirradiation of the examination subject from different directions, the x-ray beam 4 rotates around an axis 4a by deflection of the electron beam 5 on the annular anode 3.
A control unit 14 operates the deflection coil 9 so that the electron beam 5 penetrates the x-ray source 2 concentrically relative to the annular anode 3 before the beginning of a scan event, until the electron beam 5 is incident on a beam catcher 15 at the closed end. The beam catcher 15 may consist, for example, of lead. Prior to reaching the beam catcher 15, the electron beam 5 is defocussed by a defocussing unit 16.
The electron beam 5 is then deflected onto the annular anode 3 by the deflection coil 9, and scans the annular anode 3 from its end 17 to its end 18. Five focus positions are shown in FIG. 1, however, there are significantly more discrete focus positions, for example one thousand. Preferably, however, the focus is continually shifted by a traveling wave, so that scanning is defined by the detector sampling. The x-ray beam 4 thus rotates in a direction opposite to the direction of the electron beam 5, and is shown in its final position in FIG. 1, at which point the scan event is terminated.
Another deflection of the annularly guided electron beam 5 subsequently takes place, with a new scan event beginning with the deflection of the electron beam 5 onto the end 17 of the annular anode 3.
It is also possible to scan the annular anode 3 with an electron beam 5 moving in the clockwise direction, i.e., from the end 18 to the end 17 of the annular anode 3.
The radiation detector 10 is disposed relative to the annular anode 3 so that the x-ray beam 4 can pass by the detector 10 before the beam 4 enters the measurement field 1. The x-ray beam 4 is incident on the radiation detector 10 only after emerging from the measurement field 1.
As can be seen in FIG. 2, a patient on a support 20 is moved through the measurement field 1 while the beam focus is rotated on the annular anode 3. A defined measurement volume of the patient is thus helically scanned, or is scanned over a portion of a helix. From the data acquired thereby, the computer 11 can calculate both tomograms for predetermined transverse slices of the patient and shadowgraphs (conventional x-ray images) for defined projection angles. The particular projection angle can be selectable. A shadowgraph should preferably be produced in lateral and anterior-posterior projection. In order to double the number of image lines in the shadowgraph, the data from projections from focus positions offset by 180° can be used. Except for the central ray and at the level of the rotational center, these projections in fan geometry will result in portions of the image being projected onto different detector positions, therefore, some deterioration in the image quality must be expected. This can be seen in FIG. 3, wherein the patient is shown in cross section. Details of the examination subject image outside of the rotational center (axis 4a), for example the detail 22, are projected onto different points in the image plane, given a fan-beam projection from opposite directions, as can be seen, for example, with respect to points 23 and 24 which have different spacings from the axis 25.
To avoid these disadvantages, data corresponding to parallel projections can be calculated from the data of the helical movement for arbitrary projection angles, as shown in FIG. 4.
Four focus positions 26, 27, 28 and 29 are shown in FIG. 4, with the associated parallel rays which are incident on the projection plane 30.
An image consequently arises after n revolutions of the focus, or 2 n measured lines. A calculation of additional image lines by interpolation is also possible.
Because a two-dimensional convolution is usually implemented to improve the image quality, the image for the region n-m (or 2 n-m) lines can be portrayed in so-called final quality, while the remaining region is portrayed in a preliminary processing condition, given a convolution core over a 2 m line range. Looking at this image, the attendant or physician can recognize when the desired examination region is scanned, and the helical exposure is to be aborted. This can be implemented manually, such as by a so-called dead man circuit.
The method disclosed herein can also be used in computer tomography systems having a measuring system of the type with a conventional x-ray tube and radiation detector, with means for mechanically rotating these components around an axis. The method can be used to particular advantage, however, in a system of the type described above with an annular anode, because such systems do not require pauses for cooling, due to limited x-ray power, and thus helical computer tomography exposures of larger volumes can be undertaken in a shorter time without interruption. The method is also particularly useful for conducting an examination of a standing patient wherein the time lost due to the generation of an additional shadowgraph is highly disadvantageous, because the patient, without a patient support, is more likely to move between exposures, and in some instances standing for a length of time may be difficult for certain patients.
An arrangement of the computer tomography apparatus for conducting an examination of standing patient is shown in FIG. 5, with the measurement system 31 being horizontally oriented relative to a platform 32 on which the examination subject stands. The measurement system 31 is mounted on supports 33 so as to be height-adjustable in the vertical direction, as indicated by the double arrows. A helical exposure of a standing patient is thereby possible.
The image quality of the shadowgraph is adequate in all instances for computer tomography systems having annular anodes with which exposures of thin layers, possible with a multi-line detector are provided, and can even be superior to current shadowgraphs. Due to the prevention of parallax errors, the creation of the shadowgraphs from parallel projections constitutes a clear advantage over the conical projection used in conventional x-ray exposures, as well as in comparison to the cylindrical projection which is conventionally used to make a shadowgraph in a computer tomography apparatus.
Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
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A computer tomography apparatus has an x-ray source and a radiation detector which permit a patient to be helically scanned to obtain a tomogram of the patient. Since it is frequently desirable to obtain a conventional x-ray image (shadowgraph) of the patient as well, a method is disclosed which permits the computer used to generate the tomogram to calculate such a shadowgraph of the patient from the data acquired for the tomogram, for desired projection directions. This data is acquired, and the shadowgraph obtained, simultaneously with the exposure used to produce the tomogram.
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FIELD OF THE INVENTION
The present invention relates to a shuttle, preferably of plastic, for embroidery and quilting machines and includes a housing and a base plate, which can be connected therewith, on which a thread tension device is positioned which adjusts the thread tension.
BACKGROUND OF THE INVENTION
Shuttles for embroidery and quilting machines, used all over the world today, are preferably made of steel and only approximately 10% of plastic. The average age of a shuttle is 12 to 15 years. But shuttles which have been used for 30 or more years are not uncommon. As a result, shuttles of various ages are used in an embroidery machine, which have certain differences with respect to the mass at the shuttle hole and of the cover, or where the cover itself has been changed. For this reason all efforts to automate the emptying, cleaning, re-filling and setting if the thread tension of current shuttles have failed. Although attempts have been made within the past ten years to change certain operations of these steps into separate automated operations, such attempts have been only moderately successful. All shuttles need to be identical for automation and they must be newly designed for handling by machine.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to develop a novel shuttle for embroidery and quilting machines, which can be fully and automatically emptied, cleaned, filled and threaded again as well as in which the thread tension can be adjusted exactly. It is a further object of the present invention to be able to manufacture the shuttle considerably more economically than conventional shuttles. Conversion of embroidery machines to the new shuttles is only economical for the embroidery industry under the last mentioned conditions. Acquiring the new shuttles alone is not enough. Appropriate bobbin winding machines and shuttle processing machines, in which the shuttles are emptied, cleaned, the bobbins inserted, the threads threaded, the thread tension set, the shuttles inserted into an insertion guide and finally the insertion guides placed on a transport carriage, are all automated. But for full automation, appropriate transport devices and devices for removing and replacing the shuttles in the embroidery and quilting machine are also required. But the key to the entire, fully automatic operation is the shuttle. Of particular importance for the automation in this case is a simplified exterior design of the shuttle. This is achieved in accordance with the present invention when the base plate forms at least a portion of the glide face of the shuttle and when the means which are part of the thread tension device are located on the base plate in the interior of the shuttle.
Further characteristics in accordance with the present invention are set forth in the dependent claims which are described as to their meaning and purpose in the description below. Three preferred embodiments of the subject of the invention are shown in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal cross section of a shuttle in accordance with the invention, in which the entire base plate can be removed from the housing;
FIG. 2 is a bottom view of the shuttle in accordance with FIG. 1;
FIG. 3 is a longitudinal cross section through a shuttle wherein the base plate is pivotally connected with the housing around an axis provided in the area of the tip, crosswise to the longitudinal direction;
FIG. 4 is a bottom view of the shuttle in accordance with FIG. 3, in the closed position;
FIG. 5 is a side view in the opened position;
FIG. 6 is another embodiment of a shuttle in longitudinal cross section, wherein the base plate is pivotally connected with the housing around an axis positioned vertically to it in the tip of the shuttle;
FIG. 7 is a bottom view of the shuttle in accordance with FIG. 6;
FIG. 8 is a cross section of the shuttle in accordance with FIG. 7 in the area of thread tensioning, and
FIG. 9 is a cross section of the shuttle in accordance with FIG. 7 in the area of the thread exit opening.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The terminology in this specification has been intentionally changed in contrast to the known embroidery machine shuttles. Thus, such terminology alteration is also intended to make clear the completely different design of the shuttle. The embroidery machines which have remained essentially the same for more than 100 years customarily have a shuttle body which receives a bobbin and a cover, which is pivotal in the shuttle body around an axis extending crosswise to the longitudinal axis, by means of which the bobbin is retained in the shuttle body. In this case, the edge of the shuttle body represents the glide face. The pivotal cover is offset towards the interior with respect to this glide face. It has a thread tensioning spring on its exterior, for example directed towards the slide face, on which a tensioning clip acts, by which the thread tension can be set. The thread is pulled off the bobbin, run to the outside through the cover, under the tensioning spring back inside through the cover and then laterally outside through the hole in the shuttle body. Reference is made to Austrian Patent AT-A-61077, purely by means of example. Presently, all embroidery machine shuttles have this design.
In connection with the embroidery machine shuttle according to the present invention, the part which has so far been called "shuttle body" will now be called the housing. The part formerly called "cover" will now be called base plate 2. This for the additional reason that the base plate 2 not only has a closing function but, in contrast to the known objects, at least partially forms the glide face of the shuttle. This considerably increased support face in the direction of the shuttle race, instead of the almost sharp edge of a conventional shuttle, together with the use of a certain plastic, metal or steel alloy, results in optimum sliding properties. Damage to the shuttle race is practically impossible, because the point of the shuttle is always supposed to be made of plastic. Now the bobbin 4 n longer lies inside the shuttle body to a large degree, but rather on the base plate 2, which is appropriately equipped with bobbin mounting attachments. The shuttle housing now has the cover function which had previously been assigned to the cover. The former terminology is subsequently no longer used, and also no comparisons with the shuttles in accordance with the known state of the art can be made.
The embroidery machine shuttle in accordance with the present invention is essentially made of plastic. It has the already mentioned main components, namely the housing 1 and the base plate 2. Only in the area of the shuttle point 3 does a part of the housing 1 also form a part of the glide face. Otherwise, the base plate 2 takes over this function, as can be clearly seen in FIG. 1. The bobbin 4, shown in the drawings by a dotted line, lies on the base plate 2 and its position is determined by a bobbin mounting 5. In the direction towards the point, the position of the bobbin 4 is defined by the front mounting plate 6. The mounting plate 6 is a part of the bobbin mounting 5, which can be fixedly connected with the base plate 2 or can be integral with the base plate 2. At the back end of the shuttle, the bobbin mounting 5 changes over into a rear thread guide element 7.
The thread F, pulled off the bobbin 4, is drawn through a slit ending in a thread guide opening and runs around the rear thread guide element 7, which is appropriately arc-shaped, to the thread tension device which is described below.
The thread F leaves the chamber in which the bobbin 4 is seated directly through the lateral thread hole 8. The thread hole 8 is embedded in a bracket 9 extending vertically to the base plate 2 on its side. The thread hole 8 has a metal o ceramic coating to improve the running or frictional properties, in the present embodiment in the shape of an impressed eye 14 of metal or ceramic material. The housing 1 is mounted on the base plate 2 in a form-fitting and frictional manner. To facilitate such mounting, a flexible stop cam 10 is extruded from the interior of the housing in the area of the shuttle tip 3, which lockingly engages a projection 11 on the mounting plate 6. A corresponding form-fitting receptacle 12 is embedded in the rear wall of the housing 1. In the closed operational state of the shuttle, the conventional cam 13 on the thread guide element 7 rests in the form-fitting receptacle 12.
In the area between the rear thread guide element 7 and the thread hole 8, the thread F is routed through a thread tension device. The thread tension device comprises an upper pressure plate 20 fastened on the base plate 2, directly following the thread guide element, crosswise to the longitudinal direction of the shuttle. The upper pressure plate 20 is fastened with rivets 21. The upper pressure plate 20 is drawn upwards in an arched shape in the direction towards the shuttle end. A lower counterpressure spring 22 is fastened with two rivets 23 in the forward area of the base plate 2. The lower counterpressure spring 22 extends over almost the entire length of the base plate 2. With its free end the lower counterpressure spring 22 abuts below, under spring pressure on the upper pressure plate 20. The free end of the lower counterpressure spring 22 is downwardly curved. Rounding of the upper pressure plate 20 and the lower counterpressure spring 22 in the area where the thread F enters the thread tension device is required so that no unraveling twist acts on the thread, which might result in knot formation and breaking of the thread. The flat clamping of the thread F between the upper pressure plate 2 and the lower counterpressure spring 22 can be regulated by a slide 24. The slide 24 presses on the lower counterpressure spring 22 from below. The closer the slide 24 is pushed in the direction of the upper pressure plate 20, for example in the direction towards the back end of the shuttle, the greater is the clamping force between the pressure plate 20 and the counterpressure spring 22. As the clamping force increases, the set thread tension increases. The slide 24 is slidingly maintained in a slide guide 25 embedded in the base plate 2. It is possible to displace the slide 24 within the area of the slide guide 25 from the direction of the underside of the base plate 2. Such a thread tension device is particularly suited to automatically set the thread tension to a reproducible value in a suitably constructed device.
So that the slide 24, because of the intense back and forth movements of the shuttle, in particular at high speed, does not shift by itself because of these dynamic forces, it is possible to press into the base plate 2 a delicate grid, so that the slide 24 remains in the desired position. This grid, preferably made of a plurality of parallel grooves vertically to the direction the slide guide 25 extends, is provided on the inside of the base plate 2 and the lower counterpressure spring 22 keeps the slide 25 engaged with the grid.
The embodiment shown in FIGS. 1 and 2 is based on a complete separation of the base plate 2 and the housing 1 when a fresh bobbin 4 is inserted. Such a method has the advantage that the main components can be cleaned in a particularly easy manner and that one or the other component can be immediately replaced in case of a defect, without assembly operations being required for this. In case of destruction of the sensitive shuttle point 3 of the housing 1, in particular, the housing 1 can be replaced immediately, because all shuttle housings 1 and base plates 2 are identical.
No further mention is made of the already described and only minimally changed parts of the shuttle in the two embodiments in accordance with FIGS. 3 to 5 and 6 to 9, which will be described below. Identical parts have been assigned identical reference numerals to the extent that the need to be at all mentioned.
The essential characteristic of the embodiment of the shuttle of the present invention in accordance with FIGS. 3 to 5 lies in that the base plate 2 is pivotally seated in the housing 1 on a horizontal pivot axis 15. The pivot axis 15 extends parallel to the base plate 2 as well as vertically to the longitudinal axis of the shuttle. The part of the housing 1 which forms the point 3 of the shuttle is drawn down as far as the lower level of the base plate 2. In this way the front part of the housing 1 forms a portion of the slide face of the embroidery machine shuttle. Thus, the connection between the housing 1 and the base plate 2 in the area of the shuttle point 3 by the pivot axis 15 is permanent in this embodiment and a locking mechanism is only needed at the end of the shuttle. In the example shown, a stop cam 16 is provided on the inside of the housing 1, over which the end of the base plate 2 locks, so that the cam 16 comes to rest in a recess 17 in the base plate 2. A part of the bobbin mounting 5 and of the rear thread guide element 7, together with the base plate 2, form a unit. For this purpose a housing area 18 has been taken over by the base plate 2, for which reason the housing 1 itself has a corresponding housing recess 19 of the same size. This is particularly clear in FIG. 5, which shows the shuttle of the invention in an opened state. The further elements are the same as in the embodiment in accordance with FIGS. 1 and 2, as previously described. No further mention will be made of this.
Another embodiment of the embroidery machine shuttle in accordance with the present invention is illustrated in FIGS. 6 to 9. In contrast to the previously described embodiments, the housing 1 and the base plate 2 are connected rotatably with respect to each other on a vertical pivot axis 15, again in the area of the shuttle tip 3. In this embodiment, the actual shuttle point 3 is formed by the base plate 2. In this embodiment, the bobbin mounting 5 extends almost completely over the entire length of the shuttle and forms a housing area 18 directly disposed on the base plate 2. When opening the shuttle there is an apparent displacement in the longitudinal direction. However, actually only a displacement of the housing 1 on the pivot axis 15 takes place. Only because the bobbin mounting 5 also includes a relatively larger housing area 18 does this apparent longitudinal division of the shuttle take place. It can be seen from FIG. 8, which represents a cross section of the shuttle in accordance with FIG. 7 in the area of the rear thread guide element 7, the base plate 2 together with the bobbin mounting 5 represent almost two-thirds of the circumference of the shuttle, while in this area the housing 1 only represents one-third. The housing 1 is mounted on the base plate 2 in a form-fitting manner with flexible stop cam 26 engaging with a projection of base plate 2. The rear thread guide element 7, clearly discernible here, is simultaneously a stop plate for the bobbin 4 and has a thread guide slit 27. The latter extends downward vertically to the base plate 2 as far as approximately half the height of the bobbin 4. The thread which is pulled off the bobbin 4 is routed through the thread guide slit 27 towards the back and around the thread guidance element 7 towards the front, passing the thread tension device 20, 22 and leaving the shuttle through the thread hole 8. FIG. 9, which represents a cross section through the shuttle in the area of the thread hole 8, clarifies such routing. This is at the same time the area of the largest cross section. The slide 24 can be seen here clearly as it presses from below against the lower counterpressure spring 22.
Because the housing 1 can be made of plastic, the shuttles in accordance with the present invention may also have considerably more complex exterior shapes, as shown by the embodiments in accordance with FIGS. 3 to 9. The asymmetric shape of the housing 1 with respect to its longitudinal axis is particularly noticeable. Thus the rear part of the shuttle becomes more slender. The cross sectional surface in particular is reduced steadily, approximately from the end area of the slide guide 25 and extending towards the end, for example the circumference is reduced only in the last third or at least fourth of the shuttle. In contrast to conventional shuttles, this results in a reduction of the draw of the needle thread and in an extension of the time during which the thread guide can pull back the thread.
For the purpose of clarification, the mode of operation of the embroidery machine is briefly addressed.
It is the job of the shuttle to pass through the loop of the needle thread with its point, so that the front thread is kept on the backside of the material. To this end the shuttle is pushed forward at the exact time when the needle again arrives at its culmination point after a short reverse movement. The shuttle passes with its point through the loop created by the reverse movement. By the time the needle has arrived at its front reversing point, approximately half of the shuttle has already passed through this loop. Starting from the middle of the shuttle, the needle already moves backwards. During this backward movement the shuttle continues to be pushed through the loop. Due to the novel shape of the shuttle, where the rear part of the shuttle is more slender or has a smaller circumference, less thread, which must always be pulled back by the thread guides, is drawn out with each stitch.
In the course of practical application this means that with the new construction the front thread is pulled back and forth to a lesser degree through the material, which demonstrably leads to a reduced frequency of needle thread breakage.
Since this is a completely new generation of embroidery machine shuttles, it is not possible to illustrate all conceivable embodiments. However, the essential and basic principle of the present invention is that the shuttle no longer runs on the edge of its housing as before, but rather on its base plate 2, which also takes over the function of the previous cover.
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The embrodiery machine shuttle, preferably made of plastic, has two main components, namely a base plate and a housing which can be fastened on the base plate. The base plate forms the slide face of the shuttle. For this reason the elements required for thread tension are placed in the interior of the shuttle. A bobbin is maintained in the correct position by a bobbin mounting and a part thereof forms a rear thread guide element. The thread is drawn off the bobbin and routed to a thread hole through and around the thread guide element between an upper pressure plate and a lower counterpressure spring. The thread tension can be easily adjusted from the outside with a slide. The shuttle according to the present invention is suited, together with a corresponding shuttle processing machine, for automatic emptying, cleaning, filling with a fresh bobbin, threading and setting the thread tension.
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BACKGROUND OF THE INVENTION
1. Field Of The Invention
The present invention relates to carbonless copying systems and in particular to microcapsules which are useful in connection with such systems and which comprise minute discrete droplets of liquid fill material including an initially colorless chemically reactive color forming dye precursor and a carrier therefor encapsulated within individual, rupturable, generally continuous shells.
2. Description Of The Prior Art
Impact or pressure sensitive carbonless transfer papers have recently come into wide usage in the U.S. and throughout the world. Ordinarily, such papers are printed and collated into manifolded sets capable of producing multiple copies. In this connection, pressure applied to the top sheet causes a corresponding mark on each of the other sheets of the set.
The top sheet of paper, upon which the impact or pressure is immediately applied, ordinarily has its back surface coated with microscopic capsules containing one of the reactive ingredients which interreact to produce a mark. A receiver sheet, placed in contact with such back face of the top sheet has its front surface coated with a material having a component which is reactive with the contents of the capsule so that when capsules are ruptured upon impact by stylus or machine key, the initially colorless or substantially colorless contents of the ruptured capsules react with a co-reactant therefor on the receiver sheet and a mark forms on the latter corresponding to the mark impressed by the stylus or machine key.
In the art, impact transfer papers are designated by the terms CB, CFB and CF, which stand respectively for "coated back", "coated front and back", and "coated front". Thus, the CB sheet is usually the top sheet and the one on which the impact impression is directly made; the CFB sheets are the intermediate sheets, each of which have a mark formed on the front surface thereof and each of which also transmits the contents of the ruptured capsules from its back surface to the front surface of the next succeeding sheet; and the CF sheet is the last sheet and is only coated on its front surface to have an image formed thereon. The CF sheet is not normally coated on its back surface as no further transfer is desired.
While it is customary to coat the capsules on the back surface and to coat the co-reactant for the capsule contents on the front surface of each sheet, this procedure could be reversed if desired. Further, with some systems, coatings need not be used at all and the co-reactive ingredients may be carried in the sheets themselves, or one may be carried in one of the sheets and the other may be carried as a surface coating. Further, the co-reactive materials may each be microencapsulated. Patents illustrative of many of the various kinds of systems which may incorporate such co-reactive ingredients and which may be used in the production of manifolded transfer papers include, for example, U.S. Pat. No. 2,299,694 to Green, U.S. Pat. No. 2,712,507 to Green, U.S. Pat. No. 3,016,308 to Macaulay, U.S. Pat. No. 3,429,827 to Ruus and U.S. Pat. No. 3,720,534 to Macaulay et al.
The most common variety of carbonless impact transfer paper, and the type with which the present invention is utilized, is the type illustrated, for example, in Green U.S. Pat. No. 2,712,507 and Macaulay U.S. Pat. No. 3,016,308 wherein microscopic capsules containing a liquid fill comprising a solution of an initially colorless chemically reactive color forming dye precursor are coated on the back surface of the sheet, and a dry coating of a coreactant chemical for the dye precursor is coated on the front surface of a receiving sheet.
Many color precursors useful in connection with carbonless copying systems are known to those skilled in the art to which the present invention pertains. For example, specific reference is made to the color precursors mentioned in the patent to Phillips, Jr. et al, U.S. Pat. No. 3,455,721 and particularly to those listed in the paragraph bridging columns 5 and 6 thereof. These materials are capable of reacting with a CF coating containing an acidic material such as an acidleached bentonite-type clay or the acid-reactant organic polymeric material disclosed in the Phillips, Jr. et al U.S. Pat. No. 3,455,721 patent. Many of the color precursors disclosed in the U.S. Pat. No. 3,455,721 patent referred to above are capable of undergoing an acid-base type reaction with an acidic material. Other previously known color precursors are the spiro-dipyran compounds disclosed in the patent to Harbort, U.S. Pat. No. 3,293,060 with specific reference being made to the disclosure of the U.S. Pat. No. 3,293,060 patent extending from column 11, line 32 through column 12, line 21. The color precursors of Harbort, as well as the color precursors of Phillips, Jr. et al are initially colorless and are capable of becoming highly colored when brought into contact with an acidic layer such as an acid-leached bentonite-type clay or an acid-reacting polymeric material, or the like.
Generally speaking, color precursor materials of the type disclosed by Phillips, Jr. et al U.S. Pat. No. 3,455,721 and by Harbort U.S. Pat. No. 3,293,060 are dissolved in a solvent and the solution is encapsulated in accordance with the procedures and processes described and disclosed in U.S. Pat. No. 3,061,308 to Macaulay, U.S. Pat. No. 2,712,507 to Green, U.S. Pat. No. 3,429,827 to Ruus and U.S. Pat. No. 3,578,605 to Baxter. In this connection, it should be mentioned that the present invention is particularly useful in connection with microcapsules of the type disclosed by Ruus U.S. Pat. No. 3,429,827 which are produced by an interfacial polycondensation procedure.
Solvents known to be useful in connection with dissolving color precursors include chlorinated biphenyls, vegetable oils (castor oil, coconut oil, cotton seed oil, etc.), esters (dibutyl adipate dibutl phthalate, butyl benzyl adipate, benzyl octyl adipate, tricresyl phosphate, trioctyl phosphate, etc.), petroleum derivatives (petroleum spirits, kerosene, mineral oils, etc.), aromatic solvents (benzene, toluene, etc.), silicone oils, or combinations of the foregoing. Particularly useful are the alkylated naphthalene solvents disclosed in U.S. Pat. No. 3,806,463 to Konishi et al.
In the color forming systems outlined above, as will be appreciated by those skilled in the art, the color precursors are conventionally contained in pressure rupturable microcapsules which are included in the back coatings of the sheets of carbonless copying manifolded sets. Further, it will be appreciated that the acidic coatings are generally utilized as front coatings with the color precursor material in a solvent therefor being transferred from an adjacent back coating to the acidic layer front coating upon rupture of the capsules which contain the color precursor material.
Although microcapsules have been extensively used in connection with carbonless copying systems in the past, one particular shortcoming, which has continued to detract from such systems, both from an economical and from an operational point of view, is the inadvertent or unintentional development of color on the CF coatings. Free colorless dye precursor has often been present in CB coatings in the past due to limitations of the encapsulation procedure, or due to accidental capsule rupture which often occurs during handling, coating processes, printing processes, etc. This free precursor often causes discoloration by contacting the CF ingredients through the base paper in the CFB sheets and from sheet to sheet in a manifolded set or form. This discoloration, which is sometimes referred to as blush, offset, bluing, etc., is highly objectionable and undesirable in a copying or imaging system.
High surface area fillers such as Syloids (synthetic silicas) have been utilized in admixture with the microcapsules in CB coatings to prevent blush with some success. These fillers absorb free dyes or solvents or both and substantially reduce the quantity of dye material which is free to be transferred to an adjacent CF coating. However, the inclusion of such additives in CB coatings increases the cost of the latter and often such additives operate to reduce image intensity. The foregoing concepts as well as other prior art procedures directed to alleviating the problem of inadvertent CF discoloration in carbonless copying systems are disclosed in U.S. Pat. No. 3,617,334 to Brockett et al; U.S. Pat. No. 3,481,759 to Ostlie; and U.S. 3,625,736 to Matsukawa et al. Also note British Pat. Nos. 1,232,347 and 1,252,858 which disclose the intermixture of finely divided particles of starch or starch derivatives with microcapsules for the purpose of reducing stain-formation during the processing of pressure sensitive recording paper. British Pat. No. 1,252,858 also discloses the use of hard, inert beads (such as fine glass beads) and short cellulose fibers or floc as a stilt material to guard against unintended capsule rupture and the consequent development of coloration and smudging from frictional pressures encountered in the handling and use of carbonless copying papers.
SUMMARY OF THE INVENTION
In accordance with the concepts and principles of the present invention, unintended CF discoloration is substantially avoided in colorless copying systems utilizing CB coatings comprising microencapsulated dye precursor solutions through the use of an additive which is included in the encapsulated liquid fill material. More specifically, the present invention provides improved microcapsules which are useful in connection with carbonless copying systems and which comprise minute discrete droplets of liquid fill material including an initially colorless chemically reactive color forming dye precursor and a carrier therefor encapsulated within individual, rupturable, generally continuous polyamide shells. These microcapsules are produced by a process which comprises the step of incorporating in the fill material, an amount of an epoxy or polystyrene resin effective to render the microcapsules resistant to inadvertent release and transfer of the fill material. More specifically, the process is utilized in connection with polyamide shells which are formed by interfacial polycondensation and even more particularly, in the highly preferred form of the invention, the shells are formed from a polyterephthalamide and the resin which is added to the fill is an epichlorohydrin/bisphenol A epoxy resin. The present invention has been found to be particularly useful in conjunction with microcapsules which contain a dye precursor such as Michler's hydrol, p-toluene sulfinate of Michler's hydrol, methyl ether of Michler's hydrol, benzyl ether of Michler's hydrol and the morpholine derivative of Michler's hydrol.
In another aspect, the present invention provides microcapsules which are useful in connection with carbonless copying systems. The microcapsules comprise minute, discrete droplets of liquid fill material including an initially colorless chemically reactive color forming dye precursor and a carrier therefor. Each of the droplets is individually encapsulated in a rupturable, generally continuous polyamide shell and an epoxy or polystyrene resin is incorporated in the fill material in an amount effective to render the microcapsules resistant to inadvertent release and transfer of the fill material.
DETAILED DESCRIPTION OF THE INVENTION
In carbonless copying systems, premature discoloration or color development on the CF is objectionable. Discoloration can occur during coating, processing and handling of the carbonless paper. It can also occur in forms prepared from carbonless paper and in rolls of carbonless paper under ordinary conditions of storage and ageing, or it can occur as the result of a combination of one or more of the foregoing conditions. Premature discoloration is usually due to the contact and reaction between free (unencapsulated) precursor or its decomposition products in the CB coating and the record-developing material in the CF coating. This could be a direct physical contact, an indirect contact brought about by the presence of a low vapor pressure precursor or both. Free precursor generally results because a small amount of precursor initially escapes encapsulation, because capsules leak, or because capsules are ruptured during coating, processing or handling operations.
In accordance with the present invention, objectionable premature discoloration or color development on CF coatings is substantially eliminated by incorporating in the microencapsulated fill material, an amount of an epoxy or polystyrene resin which is effective to render the microcapsules resistant to inadvertent release and transfer of the fill material. The concepts and principles of the invention have utility with all types of microcapsules having a polymeric shell and the invention is particularly useful in connection with microcapsules having a polyamide shell. In its preferred form the invention is utilized in connection with polyamide shells which have been formed by an interfacial polycondensation reaction in accordance with the procedures disclosed in the patent to Ruus, U.S. Pat. No. 3,429,827.
The present invention contemplates the incorporation of either an epoxy resin or a polystyrene resin in the intended fill material prior to the formation of microcapsules. The preferred polystyrene resin is Styron 666U, a commercial product of the Dow Chemical Company. Styron 666U is a general purpose polystyrene having a Vicat softening point of 212° F (ASTM method D1525) and an Izod impact strength of 0.2 ft lbf/in of notch at 73° F (ASTM method D256). This material also has a specific gravity of 1.04 (ASTM method D792) and a melt viscosity of 1800 poises (ASTM method Rate B D1703). The preferred epoxy resin is Epon 1002, a commercial product of Shell Chemical Company. Epon resin 1002 is an epichlorohydrin/bisphenol A-type solid epoxy resin having the following typical molecular structure: ##STR1## Epon 1002 has a viscosity of 1.7 to 3.0 poises when measured at 25° C by the Bubble-Tube method (ASTM D154). Moreover, Epon resin 1002 has an epoxide equivalent of about 600 to about 700 (ASTM D1652-59T). Another highly preferred epoxy resin is Epon resin 1001 which has a viscosity of 1.0 to 1.7 poises and an epoxide equivalent of 450 to 550. More generally, epoxy resins having an epoxide equivalent within the range of from about 350 to 2500 should perform reasonably well for the purposes of the present invention. The amount of resin to be incorporated in the microcapsules ranges from 1 to 10% based on the dry weight of the capsules with a particularly preferred amount being approximately 5%. The amount of resin incorporated in the fill material should also be within the range of from about 1.3 to about 13.3% by weight based on the total weight of the solvent which forms the bulk of the fill material. In this latter connection, the particularly preferred quantity of resin is about 6.7 weight percent based on the total weight of the solvent.
EXAMPLE 1
In this Example, prior art microcapsules having a fill material which does not contain a polystyrene or epoxy resin were produced for comparison purposes. 1.00 grams of p-toluene sulfinate of Michler's hydrol (PTSMH) were admixed with 20.0 grams of dibutyl phthalate (DBP) solvent and this admixture was warmed slightly on a hot plate until a clear solution (solution A) was obtained. Thereafter solution A was allowed to cool to room temperature. Then, 3.26 grams of terephthaloyl chloride were added to 10.0 grams of DBP solvent and this mixture was also warmed slightly on a hot plate until a clear solution (solution B) was obtained. Solution B was then also allowed to cool to room temperature. After solutions A and B were prepared, 100 ml of an aqueous solution containing 2.0 weight percent Elvanol 50-42 (a commercial product of E. I. duPont De Nemours & Co. which is a polyvinyl alcohol having a hydrolysis of 87 to 89 percent and a viscosity of 35 to 45 cps. in a 4% aqueous solution at 20° C as determined by the Hoeppler falling ball method) were placed in a semi-micro Waring blender and then solutions A and B were mixed together at room temperature and the resultant solution was added to the Elvanol solution in the blender. The blender was activated and high shear agitation was continued for about 2 minutes until an emulsion having a dispersed phase particle size of about 5 to 6 microns was obtained. In this emulsion, the continuous phase was the aqueous solution containing the Elvanol polyvinyl alcohol and the dispersed phase was the DBP solution of PTSMH and terephthaloyl chloride. The emulsion was then transferred to a suitable container, such as a beaker, and was stirred with a variable speed mechanical stirrer at 300 to 500 rpm while an aqueous solution containing 1.86 gms of diethylene triamine, 0.96 gms of sodium carbonate and 20 ml of water was added. Stirring was continued at room temperature for about 24 hours until a stable pH was observed. By this time, the particles of dispersed phase had become individually encapsulated in a polyamide shell. The slurry containing the microcapsules and having the Elvanol polyvinyl alcohol binder in the continuous phase was then drawn down on a 13 pound neutral base continuous bond paper sheet at a coating weight of approximately 2.34 to 3.04 gms per square meter and the coated sheet was oven dried at a temperature of 110° C for about 30 to 45 seconds. The paper thus produced was then utilized for comparison purposes.
EXAMPLE 2
In this Example, the procedure was identical with that set forth in Example 1 except that in this instance, 1.0 gm of Epon 1002 was incorporated in solution A and the preparation of solution A was varied slightly in that the Epon 1002 and the dibutyl phthalate were first mixed and the admixture was warmed slightly on a hot plate until a clear solution was obtained. This solution was allowed to cool to room temperature before the PTSMH was added. The PTSMH was then added at room temperature and the admixture was again warmed slightly on a hot plate until a clear solution was obtained. Solution A containing Epon 1002, PTSMH and DBP was then allowed to cool to room temperature. The capsules thus produced which include a fill material containing Epon 1002 were coated onto a paper substrate in accordance with the procedure outlined in Example 1.
EXAMPLE 3
In this Example, the exact procedure outlined in Example 2 was repeated except that in this instance the quantity of Epon 1002 included in solution A is 2.0 gms. The microcapsules thus produced were coated onto a paper substrate in accordance with the procedure outlined in Example 1.
EXAMPLE 4
In this Example, the procedure outlined in Example 2 was repeated identically except that in this instance 1.0 gm of Styron 666U was utilized in solution A rather than the Epon 1002. In all other respects the procedure was the same and the resultant microcapsules were coated onto a paper substrate in accordance with the procedure outlined in Example 1.
EXAMPLE 5
In this Example, coated paper was produced by a procedure identical with that set forth in Example 4 except that in this instance solution A contained 2.0 gms of Styron 666U.
The CB papers produced in accordance with Examples 2 through 5 above were compared with the CB paper produced in accordance with Example 1. The papers were evaluated and compared (1) with regard to the intensity of the image produced in an eight-part manifolded set when the latter is subjected to normal usage, (2) with regard to ghosting and (3) with regard to blush. In each instance where CF sheets are utilized or referred to in the following evaluation and comparison procedures it should be understood that the acidic coatings thereon consist of acid-leached bentonite-type clay layers as are fully disclosed in presently pending application of Baxter, Ser. No. 125,075, filed Mar. 17, 1971 and now abandoned, the entirety of which is hereby specifically incorporated by reference.
Ghosting is defined as a secondary image transfer from a CB sheet to a CF sheet. The primary image is the original image produced on a CF sheet as a result of an imaging process such as typing, printing, etc. Secondary image transfer occurs subsequently to the original image producing operation. To measure the secondary image transfer (or ghosting), a fresh CF sheet is mated with the CB sheet in place of the original imaged CF sheet and the secondary image thus produced is examined visually at different periods. Ghosting could occur during ordinary handling of carbonless paper and is objectionable in carbonless copying systems.
Blush is an unintentional coloration on a CF coating caused by contact with free precursor from a CB coating. Blush can result from the presence of a small amount of dye precursor which initially escaped encapsulation, from leaky capsules or from capsules which are ruptured during processing or handling of the carbonless paper.
As a direct result of the foregoing evaluations and comparisons, it was determined that the papers produced in accordance with Examples 2, 3 and 4 were capable of generating an image having an intensity comparable with the intensity of the image generated by the paper produced in accordance with Example 1 while the image generated by the paper produced in accordance with Example 5 had slightly less intensity than the intensity of the image from the paper of Example 1 although the intensity of the image from the paper of Example 5 was acceptable. With regard to blush, the samples were evaluated five days after production, nine days after production and nineteen days after production. The papers produced in accordance with Examples 2 through 5 clearly exhibited less blush than the papers produced in accordance with Example 1 at all stages of the blush evaluation and comparison tests. With regard to ghosting, the papers were tested for ghosting after 5 days and after 20 days. At the end of 5 days, none of the papers produced in accordance with Examples 1 through 5 exhibited a significant tendency to ghost. After 20 days, however, each of the papers tested showed some ghosting, although in no instance was the ghosting experienced with the papers produced in accordance with Examples 2 through 5 greater than the ghosting which was experienced with the paper produced in accordance with Example 1 and in fact the paper produced in accordance with Example 2 (low concentration Epon) showed less ghosting than the paper of Example 1. Since blush was substantially reduced and image intensity was not significantly diminished, it was concluded that the paper produced in accordance with Examples 2 through 5 was superior to the paper produced in accordance with Example 1. EXAMPLE 6
In this Example, the formulations set forth in Examples 1 (without resin) and 3 (with resin) were utilized except that sodium carbonate and sodium hydroxide were used as bases and the amounts were varied to provide acidic, neutral and alkaline pH levels. In the formulations of the present Example, 0.87 gms of sodium carbonate were utilized to provide an acidic pH of approximately 6.0, 0.96 gms of sodium carbonate were utilized to provide a neutral pH of approximately 7.0 and 1.44 gms of sodium carbonate were utilized to provide an alkaline pH of approximately 8.0. In a similar manner, 0.68 gms of sodium hydroxide were utilized to provide an acidic pH of approximately 6.0, 0.77 gms of sodium hydroxide were utilized to provide a neutral pH of approximately 7.0 while 0.96 gms of sodium hydroxide were utilized to provide an alkaline pH of approximately 8.0. After the microcapsules were prepared and after the pH of the slurry had become stable, each sample was divided into three portions. One of these portions was heated to 45° C and maintained at that temperature for 2 hours utilizing an oil bath. A second portion was heated to 65° C and maintained at that temperature for approximately 2 hours utilizing an oil bath. The third portion was maintained at room temperature for use as a control. The microcapsules were then utilized for preparing CB paper in accordance with the procedure outlined in Example 1 above.
Each paper sheet was manifolded with its CB coating disposed in contacting relationship with respect to the clay coating on a sheet of CF paper. Images were developed by striking an impression on the papers with an electric typewriter and the intensity of the image was measured 20 minutes after the initial color development using a light reflectance procedure where the reflectance of the image is compared to the reflectance of the unimaged area utilizing a photovolt reflection meter. The samples were also each tested for accelerated blush and ghosting and were subjected to a drop test and liquid chromatography analyses.
CF discoloration has been variously described as blush, offset, etc. In the present disclosure, the term blush refers to a coloration on a CF coated sheet caused by contact with free color precursor present in a CB coating as a result of a small amount of precursor initially escaping encapsulation, of leaky capsules or of capsules which have been ruptured during processing or handling. The term "Accelerated Blush" refers to a test whereby capsules are intentionally broken under controlled pressure to free the dye precursor. The coated side of a CB sheet is placed against a conventional piece of paper and is passed through a manually operated test device that applies gradual increasing and decreasing pressures thereon. The CB sheet is then placed against a CF paper and the pair are placed in an oven at 50° C for various periods of time under a weight of 2 psi. The CF discoloration is measured using a photovolt reflection meter. "Ghosting" refers to secondary image transfer from a CB coating to a clay coated sheet. A primary image is the one produced on an original CF sheet by typing, printing, etc. To measure the secondary image transfer, a fresh CF sheet is mated with the CB in place of the original imaged CF and a weight of 2 psi is applied to the mated pair. The secondary image which results is examined visually at different periods. Ghosting can occur during ordinary handling of carbonless paper and is manifestly objectionable in carbonless copying systems.
In the drop test, the few drops of a capsule slurry are placed, utilizing a medicine dropper, approximately 1 inch from the top edge of a piece of CF paper held vertically. These drops are allowed to flow over the CF side of the paper and the paper is then air dried. The discoloration on the CF is due to the reaction between any free unencapsulated precursor present in the slurry and the CF coating itself. Free unencapsulated precursor is present because (1 ) a small amount of precursor initially escaped encapsulation during formulation; (2) some of the capsules have been broken during processing and handling; and/or (3) the dye precursor has been permitted to escape through the capsule shell itself.
Liquid chromatography analysis is utilized for determining precursor impurities in CB coatings. In accordance with the present Examples, the liquid chromatography analyses are given as percent p-toluene sulfinate of Michler's hydrol (PTSMH) and percent Michler's hydrol (MH). These percentages are proportional measures and not actual quantitative measures and are significant because Michler's hydrol is a hydrolysis or decomposition product of PTSMH. In this connection, there is substantial evidence that the presence of Michler's hydrol results in increased blush, ghosting and discoloration and further that Michler's hydrol is less stable than PTSMH. Thus, it is desirable to maximize the relative amount of PTSMH present while correspondingly minimizing the relative amount of MH. The liquid chromatography analyses procedure involves the extraction of all materials from the capsules with an extraction solvent. The solvent dissolves not only the materials in the capsules themselves but also any of free or unencapsulated compounds present. The extraction solvent is then analyzed using a liquid chromatograph.
The results of testing for Image Intensity and Accelerated Blush and the results of the Liquid Chromatography analyses are set forth in Table 1.
TABLE I__________________________________________________________________________ LIQUID CHROMATOGRAPHY ANALYSES pH VALUE IMAGE INTENSITY ACCELERATED BLUSH % PTSMH % MH Without With Without With Without With Without With Without WithFORMULATION: Resin Resin Resin Resin Resin Resin Resin Resin Resin Resin__________________________________________________________________________Na.sub.2 CO.sub.3 /BasicControl 8.1 7.8 58.9 54.2 84.0 95.0 77.6 93.08 22.3 6.945° C 8.2 7.8 60.1 55.1 86.0 95.0 78.8 88.8 21.2 11.1365° C 8.4 8.1 60.9 57.3 86.0 94.5 55.7 73.68 44.2 23.31Na.sub.2 CO.sub.3 /NeutralControl 6.7 6.8 52.0 53.3 82.0 93.0 96.9 100.0 Instrument45° C 6.7 6.8 51.1 52.1 81.0 93.6 100.0 100.0 didn't integrate65° C 6.7 6.7 51.1 52.5 80.0 93.2 100.0 97.7 properlyNa.sub.2 CO.sub.3 /AcidicControl 5.9 6.0 49.5 52.3 75.0 92.8 97.6 98.7 2.36 1.2645° C 5.9 6.1 43.0 45.7 77.0 92.5 96.6 98.3 3.4 1.6265° C 5.8 6.0 51.7 51.5 78.0 93.0 96.2 98.5 3.78 1.47NaOH/BasicControl 8.2 7.9 54.0 53.7 90.2 94.5 71.16 90.3 28.8 9.645° C 8.2 7.9 53.4 54.2 90.0 94.5 71.82 92.98 28.1 7.0265° C 8.2 7.9 54.2 52.9 90.0 95.0 69.18 84.9 30.8 15.1NaOH/NeutralControl 6.8 6.8 54.1 56.9 88.0 95.0 95.2 97.1 4.8 2.945° C 6.8 6.8 51.8 58.1 87.0 94.5 93.9 96.1 6.0 3.8565° C 6.7 6.8 53.8 54.9 87.0 95.0 93.7 95.7 6.28 4.23NaOH/AcidicControl 6.05 6.0 50.4 56.9 86.5 95.0 96.9 98.5 3.05 1.4845° C 6.0 6.0 50.6 53.0 90.0 95.0 95.4 99.8 4.08 0.1665° C 5.85 5.85 56.4 54.5 89.0 94.8 95.1 100.0 4.23 0.00__________________________________________________________________________
The foregoing data illustrate the effect of the presence of the resin in the microcapsulated fill material under various conditions of pH and heating. As can be seen from Table 1, blush is substantially reduced whenever the resin is used as compared to the same formulation without the resin. It is also important to note that this reduction in blush was accomplished without substantially effecting the image intensity. It can also be determined from the data of Table 1 that formulations which include the resin contain relatively less MH and relatively more PTSMH than do the identical formulations without the resin. This is significant, as explained above.
It was also determined from the foregoing testing that ghosting was significantly reduced by the inclusion of the resin in the capsule fill material. This was more apparent in the higher pH values formulations. From the drop test it was determined that CF discoloration was less with any formulation which included the resin than from the corresponding formulation without the resin. This is clear evidence of the effect of the resin in reducing the amount of free precursor in the wet formulation or at least of the effect of the resin in reducing the ability of the precursor to discolor CF coatings.
EXAMPLE 7
In this example, 1.8 grams of Epon 1002 were admixed with 20 grams of xylene and this admixture was warmed slightly on a hot plate until a clear solution was obtained. This solution was allowed to cool to room temperature and then 1.0 grams of the morpholine derivative of Michler's hydrol having the following molecular structural configuration. ##STR2## were added and the resultant mixture was again warmed slightly on a hot plate until a clear solution (solution A) was obtained. Thereafter, solution A was allowed to cool to room temperature. Then, 3.3 grams of terephthaloyl chloride were added to 10 grams of xylene and this mixture was also warmed slightly on a hot plate until a clear solution (solution B) was obtained. Solution B was then also allowed to cool to room temperature. After solutions A and B were prepared, 100ml of an aqueous solution containing 2.0 weight percent Elvanol 50-42 polyvinyl alcohol were placed in a semi-micro Waring blender and then solutions A and B were mixed together at room temperature and the resultant solution was added to the Elvanol solution in the blender. The blender was then activated and high shear agitation was continued for about 2 minutes until an emulsion having a dispersed phase particle size of about 5 to 6 microns was obtained. In this emulsion, the continuous phase was the aqueous solution containing the Elvanol polyvinyl alcohol and the dispersed phase was the xylene solution of the morpholine derivative of Michler's hydrol and terephthaloyl chloride. The emulsion was then transferred to a suitable container, such as a beaker, and was stirred with a variable speed mechanical stirrer at 300 to 500 rpm while an aqueous solution containing 3.0 gms of diethylene triamine and 20 ml of water was added. Stirring was continued at room temperature for about 24 hours until a stable pH of about 8.5 was observed. By this time, the particles of dispersed phase had become individually encapsulated in a polyamide shell. The capsules thus produced include a fill material containing Epon 1002 and the morpholine derivative of Michler's hydrol in a xylene carrier.
EXAMPLE 8
In this Example, the procedure outlined in Example 7 was repeated identically except that in this instance 1.8 grams of Styron 666U were utilized in solution A rather than the Epon 1002.
Examples 7 and 8 illustrate that different solvents can be utilized as the carrier material with the only requirement being that the particular precursor and the resin be soluble in the solvent.
EXAMPLE 9
The procedures outlined in Example 6 were repeated utilizing various Michler's hydrol derivatives as the color precursor. In this Example, the precursors utilized were Michler's hydrol, methyl ether of Michler's hydrol, benzyl ether of Michler's hydrol and the morpholine derivative of Michler's hydrol. These precursors were encapsulated with and without the resin, using the same formulations and procedures set forth above in connection with Example 6 except that in this instance only sodium carbonate was used to regulate the pH values and the formulations were mixed for 4 and 24 hours after which paper was coated in accordance with the procedure outlined in Example 1. This Example illustrates the effect of the presence of the resin on different precursors under various conditions of mixing and pH values. The drop test was performed on all of the wet formulations. The accelerated blush test, ghosting test, image intensity test and liquid chromatography analysis was also performed on the CB coatings. In conjunction with the accelerated blush test, CF discoloration from an area where capsules were not broken adjacent to the area of broken capsules on which the accelerated blush measurements are usually taken was also measured. The results of the foregoing testing are set forth in Table 2 hereinbelow.
TABLE 2__________________________________________________________________________ ACCELERATED BLUSH TEST (5 days) pH VALUE IMAGE INTENSITY Broken Capsules Unbroken Capsules MIXING TIME Without With Without With Without With Without WithFORMULATION: Hours Resin Resin Resin Resin Resin Resin Resin Resin__________________________________________________________________________1. Acid formulation 4 6.8 6.9 52.0 53.5 91.0 94.0 96.0 97.5 PTSMH 24 6.0 6.0 50.0 53.0 86.0 95.0 94.0 98.02. Basic formulation 4 7.2 7.3 58.0 59.0 91.0 96.0 96.0 97.5 PTSMH 24 8.3 8.2 58.0 59.0 91.0 95.0 95.5 97.03. Acid formulation 4 6.8 6.9 50.0 56.0 56.0 88.0 60.0 95.0 MH 24 6.0 6.0 48.0 56.0 45.0 86.0 46.0 92.04. Basic formulation 4 7.3 7.4 50.0 53.0 63.5 90.5 69.0 96.0 MH 24 8.3 8.3 49.0 53.0 60.0 82.0 65.0 94.05. Acid formulation 4 6.9 7.0 58.0 60.0 85.0 94.0 93.0 98.0 Benzyl Ether of MH 24 6.5 5.9 57.0 59.0 77.5 91.5 89.0 96.06. Basic formulation 4 7.4 7.5 57.0 60.0 84.0 93.0 91.0 97.0 Benzyl Ether of MH 24 8.4 8.3 52.0 59.0 78.5 90.0 87.0 95.07. Acid formulation 4 7.1 7.3 44.5 47.5 83.0 86.0 88.0 95.0 Methyl Ether of MH 24 6.2 6.4 44.0 44.0 65.0 78.0 80.0 94.08. Basic formulation 4 7.5 7.5 40.0 43.5 72.0 77.0 82.0 92.0 Methyl Ether of MH 24 8.4 8.3 40.0 42.5 66.0 76.0 84.0 94.09. Acid formulation 4 7.0 7.3 50.0 60.0 51.0 86.0 52.0 89.0 Morpholine der. of MH 24 6.8 7.0 43.0 60.0 42.0 85.0 48.0 91.010. Basic formulation 4 7.4 7.3 53.0 59.0 43.0 83.5 44.0 88.0 Morpholine der. of MH 24 8.2 8.5 48.0 48.0 47.5 77.0 49.0 87.0__________________________________________________________________________
From the foregoing it can be seen that the amount of blush was substantially reduced whenever the resin was incorporated in the fill material. Moreover, the drop test showed significantly less CF discoloration in each case where the resin was utilized. In addition, the use of the resin resulted in less ghosting. Significantly, this reduction in blush and in ghosting was accomplished without a significant decrease in image intensity.
While the exact mechanism which enables resins like polystyrene resins and epoxy resins to reduce blush and ghosting without reducing image intensity is not known with any degree of certainty, a number of possible explanations have been formulated. These possibilities are outlined hereinafter and it is pointed out that any one of these or any combination thereof might be involved. In the first place, the affinity of the resin to the dye material might reduce the solubility of the latter sufficiently to prevent escape of the same to the water phase during the production of the microcapsules. This will substantially reduce the presence of free precursor material after the microcapsules have been formed. This same affinity could substantially reduce the mobility of the dye precursor and therefore the ability of the same to move to an adjacent CF coating in a manifolded set. Secondly, it is possible that the resin operates to reduce the rate of decomposition of the dye precursor to less stable and more sensitive decomposition products. In this connection it is noted that PTSMH decomposes to form Michler's hydrol which discolors, ghosts and blushes much more readily than does PTSMH itself. The resin could operate to prevent such decomposition. Thirdly, the resin could operate to reduce the mobility of the solvent or of the precursors to thereby reduce the chances of the same coming into contact with the CF. This could be the result of a reduction in the vapor pressure of the solvent or of the dye precursor. Moreover, the resin should operate to increase the viscosity of the liquid fill material. Fourthly, the resin could react or polymerize with the existing capsule wall to thereby toughen the capsule walls by cross-linking, to add a second wall inside the original wall or to plug holes which were originally present in the capsule walls. Moreover, it could be that upon breakage of the capsules, the resin will cure to form a film about the solvent or the precursor to reduce the mobility of the latter and prevent contact between the same and an adjacent CF coating.
In addition to the foregoing, some precursors, such as PTSMH, are susceptible to decomposition when contacted with water, some polar solvents and/or a high pH medium. The presence of the resin additive in the fill material, in accordance with the concepts and principles of the present invention, could operate to reduce the likelihood of such contact either by increasing the hydrophobicity of the capsule shell or by reducing the affinity of the various fill materials for water, for such polar solvents and/or for high pH media.
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Disclosed is a process for preparing improved microcapsules which are useful in connection with carbonless copying systems. Also disclosed are the microcapsules themselves which comprise minute discrete droplets of liquid fill material including an initially colorless chemically reactive color forming dye precursor and a carrier therefor encapsulated within individual, rupturable, generally continuous polyamide shells formed thereabout. The process comprises the steps of incorporating in the fill material, an amount of an epoxy resin or a polystyrene resin effective to render the microcapsules resistant to inadvertent release and transfer of the fill material.
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FIELD OF THE INVENTION
[0001] The present invention generally relates to facilitating information searches over a computer network. Specifically, the present invention relates to a method and system for modifying a content based session request issued by a search engine agent to allow access to and proper indexing of a dynamic hosted web site containing information sought by the search engine agent.
BACKGROUND OF THE INVENTION
[0002] HyperText Transfer Protocol (HTTP) is used by the World Wide Web to define how messages are formatted and transmitted, and to direct the actions of web servers and browsers in response to various commands. For example, when a user enters a Uniform Resource Locator (URL) into a browser, an HTTP command is sent to the web server directing it to fetch and transmit the requested web page.
[0003] HTTP uses a client-server model. An HTTP client, such as a web browser, opens a connection and sends a request message to an HTTP server, such as a web server within a source web site, which then returns a response message, usually containing the resource that was requested. Thus, in itself, HTTP is a “stateless” protocol, i.e., it does not provide for maintaining a “session” as a user requests and interacts with various resources. Each HTTP request for a web page is generally independent of other requests. After delivering the response, the web server closes the connection, and does not retain transaction information. Each client—server connection is fresh, containing no knowledge of any previous HTTP transaction.
[0004] Internet protocols and standards provide some support for “state” information, which is information that associates individual data packets with clients and with prior network activity, assigned priority information, service class levels, and the like. “State” refers to configuration, attributes, condition, or information content. The state of a system is usually temporary and volatile, as it changes with time and will be lost or reset to some initial state if the system is switched off. One standard supporting state information specifices a limited mechanism for the exchange of state information in which two HTTP headers called “set-cookie” and “cookie” indicate an HTTP packet that includes state information contained in the payload portion. Browser software that recognizes these headers is enabled to extract the state information and save it in a local data structure referred to as a “cookie.” Depending on the site architecture, session ID information could be passed through the web server using various other data structures including the URL or form fields.
[0005] “Cookies” are the most common session managing method. Cookies can contain any information the server chooses to put in them and are used to maintain state between HTTP transactions, which are otherwise stateless. Cookies are information files for recording information sent from a web site to hardware such as a disk drive or the like in the client system. At the beginning of a session, the web site issues identification information, such as a session ID, to the client, and the browser at the client end records the identification information into a cookie. When the client accesses the web page that issued the cookie again, the information saved in the cookie is sent to the web site. This enables the web site at the server end to implement session management or customization to individual users by using the cookie information.
[0006] Another known technique for session management without using cookies implements session management by passing information as part of the URL. An example is a method for passing on session information as a parameter. A session ID is generated at the login, and this session ID is redirected to a first page as a parameter, and retained as the user moves from one page to another. The server receives the session ID passed as a parameter, and a server-side program dynamically creates a page including a hyperlink with the embedded session ID. Because the hyperlink in the page includes the session ID as a parameter, the session ID is passed on as the user moves to another link. In this manner, a unique session ID is held along a series of link-to-link movements, which makes it possible to manage users by referring to the session ID whenever necessary.
[0007] In another prior art method, when a browser sends a fresh request for a URL to a proxy server to access information on the web, the proxy server checks whether the browser is capable of handling cookies. The proxy server then finds the requested URL and removes any cookies introduced by the web site. The cookies are stored for future use. The proxy server then appends the browser's session ID to all of the links in the responsive URL, and sends the responsive page to the browser. This method therefore removes cookies and adds the session ID to the URL to maintain the state connection.
[0008] Mechanized search engines employ software agents (variously known as “robots”, “crawlers,” “spiders,” “bots,” “web wanderers,” or “automated site searchers”) to crawl (send HTTP requests) through web sites gathering URLs and other information such as the text of pages. The information gathered by the search engine agent is stored in the search engine's databases and indexed. Search engine “index servers” contain information similar to a book's index—a list of web pages that contain the words matching a particular user query.
[0009] Most search engine agents do not accept any cookies. Furthermore, adding the session ID to the URL introduces two problems for search engines. First, since the search engine index server would include the session ID as part of the page identification, it marks the same page as distinct for each session visit but not having unique content. Some search engine index servers may even tag the page as potential SPAM, since the content of each session page is (or is nearly) identical. Second, the indexed search would attempt to return each visitor to the site with the same session identification, causing the undesirable effect of commingling consumer data. Therefore there is a need for a method and system to overcome these shortcomings. In particular, it is highly desirable to do so without requiring extensive reprogramming of the web site's applications.
[0010] Web architects and designers have developed methods for maintaining “state” information for the duration of user interactions with server resources. The architecture of many web servers requires the ability to retain information between requests, when the systems become inactive. For dynamic web sites that customize a web page for individual users or contain a shopping cart function, it is especially critical to maintain state information about the user across multiple HTTP transactions.
SUMMARY OF THE INVENTION
[0011] In one embodiment of the present invention, a method of enabling a client to collect information from a server in a network environment is disclosed in which a content-based session request submitted by a client is received. A proxy session identification is injected into the content-based session request to enable access to a server. The proxy session identification is then removed from the server's response to the client. The proxy session identification is then stored for injection into the content-based session request in a subsequent content-based session request from the client.
[0012] In another embodiment of the present invention, a system for enabling a client to index information over a network is disclosed in which a proxy server capable of receiving a content-based session request communicated by a client. The content-based session request represents a first access request to at least one content server. A header intermediary module is stored on the proxy server. The header intermediary module is operable to inject a proxy session identification into the content-based session request to enable access to the at least one content server, and remove the proxy session identification from the at least one server's response to the first access request. The header intermediary module also stores the proxy session identification for injection into the content-based session request in a subsequent access request from the client.
[0013] In another embodiment of the present invention, a method of enabling session-based content searching over a network is disclosed. A content-based session request is received from a search engine agent. A proxy session identification is injected into the content-based session request. The content-based session request is transmitted to at least one content server controlling access to at least one network location that provides content sought by the search engine agent. A response is received from the at least one content server that includes the proxy session identification injected into the content-based session request. The proxy session identification is then removed from the response and stored for injection into a subsequent content-based session request issued by the search engine agent. The response is then transmitted to the search engine agent.
[0014] In yet another embodiment, an article of manufacture including a computer program carrier readable by a computer and embodying one or more instructions executable by the computer to enable session-based content searching over a network is disclosed. A proxy session identification is injected into a content-based session request received from a search engine agent. The article of manufacture processes transmission of the content-based session request to at least one content server controlling access to at least one network location that provides content sought by the search engine agent, and receipt of a response from the at least one content server that includes the proxy session identification injected into the content-based-session request. The proxy session identification is then removed from the response prior to communication to the search engine agent.
[0015] The foregoing and other aspects of the present invention will be apparent from the following detailed description of the embodiments, which makes reference to the several figures of the drawings as listed below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a diagram of client and server components and interaction with a header intermediary module in a network environment according to one embodiment of the present invention; and
[0017] FIG. 2 is a flow chart showing steps performed by a header intermediary module according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] In the following description of the present invention reference is made to the accompanying drawings which form a part thereof, and in which is shown, by way of illustration, exemplary embodiments illustrating the principles of the present invention and how it may be practiced. It is to be understood that other embodiments may be utilized to practice the present invention and structural and functional changes may be made thereto without departing from the scope of the present invention.
[0019] FIG. 1 is a flow diagram of a network environmient 100 of the present invention in which a client 130 interacts with a server 170 through a network. In FIG. 1 , the client 130 interacts with a header intermediary module 110 stored on a proxy server 120 in accordance with one aspect of the present invention. FIG. 1 depicts that the client 130 may be either a client browser 140 or a search engine agent 150 . Site requests from the client browser 140 pass through the header intermediary module 110 on the proxy server 120 unchanged. However, requests for a content-based session search initiated by a client browser 140 or a search engine agent 150 are processed by the header intermediary module 110 relative to the steps shows in FIG. 2 . In one embodiment, the search engine agent is initiated by a search engine attempting to access server-based web site information over the Internet.
[0020] Both the client browser 140 and the search engine agent 150 are capable of initiating content-based session request 160 , which may also be referred to herein as requests 160 . Each content-based session request 160 includes a header such as an HTTP header. When a content-based session request 160 is initiated by a client browser 140 or a search engine agent 150 , the header intermediary module 110 identifies the source of the content-based session request 160 from one or more identifiers in the URL, from form fields, or from any of the other header fields such as the user-agent string.
[0021] Content-based session requests 160 initiated by search engine agents 150 typically do not include state information that enable requested web sites to maintain session integrity. Because of this, search engine agents 150 can have problems accessing sites that rely on session state information. Additionally, search engine agents 150 are incapable of receiving responses from requested web sites containing state information. The present invention addresses the issue of needing to maintain a state connection while ensuring that state information is not passed to the client 130 by examining HTTP request headers and inserting a proxy session ID in the data streams of content-based session requests 160 within the server environment 170 .
[0022] For routine site traffic, the session ID maintains data specific to an individual client 130 . Although many clients 130 can access an application simultaneously, the individual session IDs keep their own data separate. Each session ID can be used to track the progress of an individual client across multiple requests to the same application. All requests by one client use the same session ID, as long as those requests occur within the lifetime of that session ID.
[0023] The header intermediary module 110 creates a “session state” for the client 130 , injecting a proxy session ID to enable the content-based session request 160 to access server resources. The injected proxy session ID may be passed as a session cookie, as part of the URL, as one or more HTTP form fields, or as any of the other HTTP header fields, such as the user-agent string. The header intermediary module 110 then ensures the injected proxy session ID is not returned to the client 130 by stripping away the proxy session ID before the server's response 190 to the content-based session request 160 reaches the client 130 . The header intermediary module 110 then stores the proxy session ID for injection upon the next content-based session request 160 from that client browser 140 or search engine agent 150 .
[0024] FIG. 2 shows a flow diagram of details of processing a request according to one embodiment of the present invention. In accordance with FIG. 1 , FIG. 2 depicts a first step 210 , during which a search engine agent 150 issues a request 160 for a specific URL. The client 130 does not pass along any session ID as part of the HTTP header. The header intermediary module 110 looks in its database for valid session information. Upon startup, no such information exists, so the proxy server 120 passes on the request 160 . A web server 180 accepts the request 160 , detects that the requester does not currently have a session, initiates a session, performs any required one-time setup, and then processes the request 160 .
[0025] In a second step 220 , the web server 180 returns a response 190 including the session information. The header intermediary module 110 extracts the session information, stores it, strips it out of an HTTP response string 200 , and returns the response 190 to the client 130 . In subsequent client requests 160 such as in step 230 , the header intermediary module 110 looks in its database for valid session identification information, injects it into the request 160 , and forwards the content-based session request 160 on to the web server 180 .
[0026] When the web server 180 returns its response 190 , in step 240 , the header intermediary module 110 examines the session information, compares it to the current session information, and updates the stored information if the new session information is different. The header intermediary module 110 then strips the session information out of the HTTP response string 200 , and returns the response 190 to the client 130 .
[0027] When the header intermediary module 110 receives an access request 160 , it determines whether the content-based session search 160 originated from a search engine agent 150 . If so, the header intermediary module 110 applies appropriate logic to inject the proxy session ID into the HTTP header. The header intermediary module 110 then identifies responses 190 and removes the proxy session ID from the data stream before the response 190 is returned to the client 130 . The header intermediary module 110 then stores the proxy session ID in a database for future injection into the content-based session request 160 when the client 130 issues further content based session requests 160 . If and when the search engine agent 150 sends additional content-based session requests 160 , they too are identified and injected with the stored proxy session ID by the header intermediary module 110 , repeating indefinitely.
[0028] The proxy session ID remains for the duration of a search engine agent's 150 session with the web server. Since the search engine agent 150 is visiting for very different purposes than most site traffic, the rationale for allowing the proxy session ID to expire does not necessarily apply. It may be preferable for proxy session IDs injected into search engine agents 150 to persist indefinitely, with no set expiration.
[0029] Further, since the search engine agent 150 does not interact conventionally with the server, but rather more passively collects data and links, in theory a single proxy session ID can be applied to all content-based session requests 160 , regardless of specific origin. In practice, it may be preferable to apply a particular proxy session ID to all requests from a particular search engine agent 150 .
[0030] Depending upon the server architecture, the session information may take any of several forms, including that of a cookie, an addition or modification to the URL, or HTTP form fields. In the present invention, however, these same mechanisms are used only within the server. For example, the server architecture of a dynamic web site may require the use of cookies. Generally, a cookie is introduced to the client 130 by including information with a Set-Cookie command in a header as part of an HTTP response string 200 . The following is an example of the Set-Cookie command in one embodiment of the present invention that is included in an HTTP response string 200 .
[0031] Upon detection of the SET-COOKIE code “SET-COOKIE: SessionlD=ABC123DEF456” in the HTTP header the header intermediary module stores the Session ID (ABC123DEF456) and injects it into future HTTP requests by including the text “COOKIE: SessionlD=ABC123DEF456” in the HTTP header.
[0032] The present method first recognizes the HTTP header in the content-based session request 160 . Routine traffic is directed to a validation/authentication process, which may entail log in with name and/or password or, in simpler deployments, entry may be allowed if the client 130 is configured to accept cookies. However, for non-routine search engine agents 150 , the header intermediary module 110 recognizes the particular characteristics of the search engine agent 150 and asserts a “proxy” cookie or proxy session ID in the first expression “SessionlD”. This proxy session ID, identified throughout the server resources or nodes, allows access to those resources.
[0033] In one embodiment, the HTTP response string 200 includes a second expression, which is an expiration date. The expiration date in the HTTP response string 200 may be set the same as routine traffic, for a longer duration, or with no expiration date at all.
[0034] In another embodiment of the present invention, the client object is parsed to determine a type of client. The client object includes a unique identifier comprised of the content-based session request 160 and at least one header. The unique identifier conveys information identifying the type of client 130 . The client object is parsed by comparing the unique identifier to a list of unique identifiers stored in a table of known clients 130 . The client object performs this comparison using pre-defined rules that determine the specific proxy session ID to inject into the client object for processing. Additionally, parsing the content-based session request 160 may also include blocking unwanted clients identified by the unique identifier. In yet another embodiment, the content-based session request 160 may be encoded such that authentication of the client according to its unique identifier includes decoding the content-based session request 160 prior to parsing.
[0035] While the computer system in the network environment 100 described is capable of executing the present invention described herein, this computer system is simply one example of a computer system. Those skilled in the art will appreciate that many other computer system designs are capable of performing the invention described herein within the network environment 100 .
[0036] For example, the embodiment described above could describe any dynamic or e-commerce site that uses a single web server computer. Most such e-commerce sites employ a plurality of web server computers organized as a server computer farm or cluster. When an e-commerce site uses only a single web server computer, the single web server computer may easily track the session state of the accessing customer. However, most e-commerce sites employ a plurality of web server computers organized as a server computer farm.
[0037] With this architecture, any of the web server computers may service any particular client data request. Customer queries are typically distributed among the web servers by a load-balancing server computer. Thus, a web server that has responded to such a request may not service a client's subsequent request. And, each servicing web server may not possess a current copy of the client's session state. There are several common solutions such as broadcasting all current session IDs to all web server computers or writing all session states to a central file system that is accessible to all web server computers. However, because search engine agents 150 do not interact with the site in a conventional sense, in one embodiment of the invention, the header intermediary module 110 maintains a unique proxy session ID for each of the web servers where the same proxy session ID is shared by all the search engine agents 150 .
[0038] Since a comprehensive series of content-based session searches 160 can require considerable bandwidth, in yet another embodiment of the invention, a load balancer (or context sensitive switch) could be used to send all content-based session requests 160 to a specific web server or servers. Furthermore, since injecting and stripping the proxy session ID will introduce additional latency, non-search engine agent content-based session requests 160 could be immediately forwarded by a load balancer to the standard web servers, thus bypassing the header intermediary module 110 .
[0039] In another embodiment of the present invention, an application of a set of instructions in a code module may be resident in the random access memory of the computer system. Thus, the present invention may be implemented as a computer program product. In addition, although the various methods described are conveniently implemented in a server reconfigured by software, one of ordinary skill in the art would also recognize that such methods may be carried out in hardware, in firmware, or in a more specialized apparatus constructed to perform the required method steps.
[0040] Any data handled in such processing or created as a result of such processing can be stored in any memory as is conventional in the art. By way of example, such data may be stored in a temporary memory, such as in the RAM of a given computer system or subsystem. In addition, or in the alternative, such data may be stored in longer-term storage devices, for example, magnetic disks, rewritable optical disks, and so on. For purposes of the disclosure herein, a computer-readable media may comprise any form of data storage mechanism, including such existing memory technologies as well as hardware or circuit representations of such structures and of such data.
[0041] It is to be understood that other embodiments may be utilized and structural and functional changes may be made without departing from the scope of the present invention. The foregoing descriptions of embodiments of the invention have been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Accordingly, many modifications and variations are possible in light of the above teachings. For example, the header intermediary module may be maintained on the proxy server 120 or remotely at a separate server coupled to the proxy server. Also, the proxy session ID may be injected into the client object in many different forms, including but not limited to appending the proxy session ID to a URL, as a cookie, or any other method of adding information to the data stream comprising the content-based session search 160 of the client 130 . It is therefore intended that the scope of the invention be limited not by this detailed description.
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In a computer network environment, a content-based session request issued by a search engine agent is modified to enable the search engine to index information from a server to maintain a state connection where the search engine agent cannot maintain session identification. The content-based session request is modified by a header intermediary module which then directs the request to target servers. The response from the web server is again modified by the header intermediary module prior to being sent to the client that issued the request. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which 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 the meaning of the claims.
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TECHNICAL FIELD
[0001] The present invention relates to sense amplifiers for reading non-volatile memory cells.
BACKGROUND INFORMATION
[0002] In memory integrated circuits, sense amplifiers detect and determine the data content of a selected memory cell. In electrically erasable programmable read only memories (“EEPROM”) and Flash memories, the sense amplifier serves two functions. First, the sense amplifier charges the bit line to a clamped value. Second, the sense amplifier senses the current flowing into the bitline due to the memory cell state. Both the reliability, in terms of endurance and retention, and the performance of the memory, in terms of access time and power consumption, are dependent on the design of the sense amplifier.
[0003] Usually, integrated sense amplifier structures are based on a differential amplifier comparing the current coming from the selected memory cell to the current of a reference cell. Reference cells can be implemented in a number of ways, including arrays of reference cells. A reference current may also be supplied by a “dummy” bit line equivalent to a standard bit line. When reference cells are employed, they are programmed once during the testing of the memory, increasing testing time.
[0004] In order to ensure good functionality of the sense, the ratio I cell /I ref , where I cell is the memory cell current and I ref is the reference current, must be maintained high enough to take account of process fluctuations in the memory and references cells as well as the impact of memory cycling. It has been shown that the speed, performance, and reliability of standard differential amplifier sense amplifiers are highly reduced for supply voltages less than 2 V.
[0005] In general, previous attempts to design sense amplifiers that do not employ reference cells are fully asynchronous and are not very suitable at a low supply voltage (i.e., V DD <1.2 V). Therefore, it would be desirable to have an improved sense amplifier design.
SUMMARY OF THE INVENTION
[0006] In one embodiment, a method of reading a memory cell comprises precharging a first bit line coupled to the memory cell. The memory cell is driven according to a programmed state of the memory cell. Latch circuitry is biased based on a differential voltage between a first node coupled to the bit line and a second node. The latch circuitry is activated and switches according to the memory cell current. An output signal indicating a direction of the latch circuitry switch is produced.
[0007] In another embodiment, a circuit comprises a first bit line coupled to a memory cell. There is a means for biasing a first input and second input of a latch to a differential voltage between a first node coupled to the first bit line and a second node. There is also a means for switching the latch according to memory cell current and a means for producing an output signal indicating a direction of the switch.
[0008] In yet another embodiment, a circuit comprises a first bit line coupled to a memory cell. A first input of a latch is coupled to the first bit line and a second input of the latch is coupled to a second node. Latch biasing circuitry is configured to bias the first input and second input of the latch to a differential voltage between a first node coupled to the bit line and the second node, the latch configured to switch after activation, the switch made according to memory cell current.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is an electrical schematic diagram of one embodiment of the invention.
[0010] FIG. 2 is an electrical schematic diagram of one embodiment of the invention.
[0011] FIG. 3 is an electrical schematic diagram of one embodiment of circuitry to provide a bias voltage to the circuit of FIG. 2 .
[0012] FIG. 4 is a flow chart showing one embodiment of the operation of the invention.
[0013] FIG. 5 is a timing diagram of one embodiment of the invention.
[0014] FIG. 6 is a block diagram showing a detectable range of memory cell current.
[0015] FIG. 7 is a block diagram showing sequencing circuitry of one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] FIG. 1 shows one embodiment of the sense circuit 10 featuring a latch 12 and latch biasing circuitry 60 . The latch 12 has two NMOS transistors 14 , 16 . The source terminal of each of the NMOS transistors 14 , 16 is coupled to a ground potential, and the gate of each NMOS transistor 14 , 16 is coupled to the drain terminal of the other NMOS transistor 14 , 16 of the latch.
[0017] In the latch biasing circuitry 60 , a bit line 46 associated with a memory cell (not shown) has a capacitor 34 . The source terminal of PMOS transistor 38 is coupled to V DD 42 and its drain terminal coupled to the bit line 46 at node BL 30 . The gate of the PMOS transistor 38 is coupled to a ground potential. The source terminal of PMOS transistor 24 is coupled to the drain terminal of PMOS transistor 38 . The gate of PMOS transistor 24 is coupled to the gate of PMOS transistor 26 (discussed below). A resistor 52 is coupled to the drain of PMOS transistor 24 . Resistor 52 is coupled to switch 56 which is coupled to resistor 54 .
[0018] A dummy bit line 48 has a capacitor 36 . The source terminal of PMOS transistor 40 is coupled to V DD 42 and the drain terminal of the PMOS transistor 40 is coupled to the dummy bit line 48 at node CL 32 . The source terminal of PMOS transistor 26 is coupled to the drain terminal of PMOS transistor 40 . The drain terminal of PMOS transistor 26 is coupled to resistor 54 and the gate of PMOS transistor 26 is coupled to the gate of PMOS transistor 24 .
[0019] The latch 12 is coupled to the latch biasing circuitry 60 . The drain terminal of PMOS transistor 24 is coupled to the drain terminal of NMOS transistor 14 while the drain terminal PMOS transistor 26 is coupled to the drain terminal of NMOS terminal 16 . The voltage terminal at the drain of NMOS transistor 14 is V 2 22 . The voltage at the drain terminal NMOS transistor 16 is V 1 58 .
[0020] With regard to FIG. 2 , the sense circuit 10 includes precharging circuitry. In one embodiment, PMOS transistor 62 , 64 have source terminals coupled to supply voltage V DD (in one embodiment, supply voltage V DD is 1.2 V; other voltages may be used in other embodiments). The gates of these transistors 62 , 64 are coupled to a precharge signal line. The drains of transistors 62 , 64 are coupled to the bit line 46 and dummy bit line 48 , respectively. In this embodiment, the bit line decoder (not shown) couples the precharge circuitry to the bit line. Any bit line decoder known to those of skill in the art may be employed with the sense circuitry.
[0021] In FIG. 3 , one embodiment of the circuitry 104 to generate bias voltage for the sense circuit is shown. The source terminal of a PMOS transistor 82 is coupled to V DD 42 and the drain terminal of the PMOS transistor 82 is coupled to the gate of the PMOS transistor 82 and the source terminal of another PMOS transistor 84 . The drain terminal of the PMOS transistor 84 is coupled to the gate of the PMOS transistor 84 and the drain terminal of NMOS transistor 86 , whose source terminal is coupled to a ground potential. The gate of NMOS transistor 86 is coupled to an inverter 80 . The inverter 80 input is the rdn signal, which is low during a read operation. During a read operation, the circuitry 104 produces an output signal, vbias, or bias voltage, which is supplied to the circuitry in FIGS. 1 and 2 .
[0022] Returning to FIG. 2 , the signals which control latches 74 , 76 and 78 are shown. Latch 78 is controlled by the signals latch and latchn. The latchn signal is an inversion of the latch signal. Latches 74 and 76 are controlled by the latchd and latchn signals. The latchdn signal is an inversion of the latchd signal. The timing of these signals will be discussed in greater detail below in FIG. 5 .
[0023] In one embodiment, shown in FIG. 4 , the read operation of a memory cell begins with initializing the dummy bit and word lines (by discharging the lines), precharging a dummy word line and a dummy bit line, and precharging the word line and bit line associated with the memory cell to be read (block 90 ). The end of the precharge operation is detected by detection circuitry (an exemplary embodiment of which is discussed below in FIG. 7 ) (block 92 ). At the end of the precharge operation, the memory cell is correctly biased for read. The memory cell drives a current according to its programmed state (i.e., the current will vary depend on whether the memory cell is programmed with a “1” or “0”) (block 94 ). The memory cell current creates a voltage variation on the bit line. This is a current to voltage conversion on the bit line. This voltage variation is amplified by the latch biasing circuitry and the inputs of the latch are biased with a differential voltage (discussed below) (block 96 ). The latch is then activated (block 98 ). The latch then switches according to the memory current (block 100 ). An output signal indicating the result of the read operation is then produced (block 102 ).
[0024] A timing diagram of one embodiment is shown in FIG. 5 . The read operation begins with an address transition detection (“atd”)signal. (For purposes of simplicity, standard address transition detection circuitry is not shown in FIGS. 2 and 3 but is well-known to those of skill in the art.) The atd signal pulse is obtained using standard address transition detection circuitry. The atd signal goes low after an internally controlled delay (the signal stays high as long as the input address bits are toggling). The pulse delay on the atd signal is used to discharge the dummy bit line and dummy word line during the initialization phase. Once this initialization phase has occurred, the precharge operation starts. After the address is verified, the prech signal goes high to begin the precharge operation. During the precharge operation, the bit line is precharged (when the signal prechB 1 goes low). Once the dummy bit line reaches the desired precharge voltage (this is detected by circuitry connected at the end of the dummy bit and word lines, which, for purposes of simplicity, is not shown in either FIG. 1 or 2 , but would be well-known of skill to the art, the precharging of the bit lines and word lines is stopped by the signals StopprechB 1 and EndprechW 1 going high. The prech signal then goes low to end the precharge operation. Delay signals d 1 and d 2 are added by delay circuitry to provide delays between the end of the precharge and latch biasing operations and the beginning of the latch activation operations (i.e., the latch signal going high and then the latched signal going high). (In one embodiment, d 1 is less than 5 nanoseconds while d 2 is less than 2 ns. However, these delays may vary in other embodiments.) Delay d 1 is the biasing latch time and delay d 2 is a security delay (communication latch time) before latching data out. After the precharge operation ends, the latch and latchd signals go high during the latch activation period. While the latchd signal is high, the latch data is valid. The access time (the time required for a read operation) is derived as follows:
[0000] Access time=Initialization delay+Precharge delay+Latch biasing delay+Latching delay+dataout delay
[0025] Returning to FIG. 2 , switch 78 is on during the precharge and biasing operations. A current can flow through the resistors R 1 54 and R 2 52 and the switch 78 . Resistors R 1 54 and R 2 52 are of equivalent value (R 1 =R 2 =R). At the end of the precharge voltage. The precharge voltage on node BL 30 is equal to V DD −R p ·Ibias 2 , where Ibias 2 is the current flowing through PMOS transistor 24 and R p is the equivalent resistance of PMOS transistor 38 biased in linear mode. On node CL 32 , the precharge voltage is equal to V DD −R p ·Ibias 1 , where Ibias 1 is the current flowing through PMOS transistor 26 and R p is the equivalent resistance of PMOS transistor 40 biased in linear mode. In one embodiment, the precharge voltage V DD −100 mV. Other precharge voltages may be used in other embodiments. Both of the voltages on nodes BL 30 and CL 32 may be made very close to V DD through selection of structure size.
[0026] Since Ibias 1 is not equal to Ibias 2 , there is a current imbalance in the circuit. A current I Rinit flows through R 1 54 , R 2 52 , and the switch 78 . Current I Rinit sixes the DC biasing conditions of the latch following the precharge operation. In one embodiment, an initial voltage V Rinit =V 2 −V 1 =(R 1 +R 2 +R switch ) I Rinit =(2R+R switch ) (again, this assumes that R 1 =R 2 =R). the current imbalance is obtained by selecting the size of certain elements of the circuitry. For example, the drive of PMOS transistor 24 can be tuned to be larger than the drive of PMOS transistor 26 by appropriately selecting the size of the transistors 24 and 26 for transistors 38 , 40 ). In one embodiment, given the voltages at nodes V 2 22 and V 1 58 , a positive differential DC voltage is obtained at the inputs of the latch.
[0027] As noted above, the memory cell current can change the voltage on the bit line 46 . The voltage variation at node BL 30 due to the memory cell current, Icell, can be explained as:
[0000]
Δ
V
BL
=
-
(
Rp
Rp
-
gm
p
24
+
1
)
·
Icell
[0000] where Rp is the equivalent resistance of transistor 38 biased in linear mode and gm p24 is the transconductance of transistor 24 biased in saturation mode. Since there is no memory cell on the dummy bit line 48 , node CL 32 is stable at its precharge value.
[0028] The voltage variation on the bit line 46 generates an amplified variation at the inputs of the latch thanks to the biasing circuitry. The variation of differential voltage V R due to the cell current can be expressed (by neglecting g ds ) as:
[0000]
Δ
V
R
=
-
gm
p
24
(
gm
p
24
+
G
p
)
·
(
G
·
gm
N
14
gm
N
16
-
gm
N
14
+
G
)
·
Icell
=
f
·
Icell
[0000] where Gp=1/Rp, gmN 16 and gmN 14 are the transconductances of transistors 16 and 14 , respectively, and
[0000]
G
=
1
2
R
+
R
switch
=
1
2
R
,
[0000] where R=R 1 =R 2 and R switch is the equivalent resistance of the switch 78 (which can be made negligible compared to R). Based on the above equations, the following is obtained:
[0000]
G
≥
gm
N
16
·
gm
N
14
gm
N
16
+
gm
N
14
This expression is used to correctly size the resistance R.
[0029] At the end of the precharge operation (after memory cell current is flowing), the inputs of the latch are biased to a differential voltage value. The value of this differential voltage V R is:
[0000] V R =V Rinit ΔV R −ƒ·I cell
[0030] When the inputs of the latch are correctly biased to the DC V R value, the latch circuitry can be activated. To activate the latch, the switch 78 can be activated. To activate the latch, the switch 78 must be OFF. Once activated, the latch switches according to the initial DC input conditions given by V R . The latch switching operation is very fast due to positive feedback. If the NMOS transistors 14 , 16 in the latch are perfectly identical (i.e., there is no mismatch is the latch circuitry), the theoretical condition to get a correct latch switching operation is |V R |≧0, where |V R | is the absolute value of the differential voltage V R . However, given a mismatch between transistors 14 and 16 , the practical condition for a latch switching operation is |V R |≧3·σ VTN , where σ VTN is the standard deviation of the threshold voltage (“VTN”) of NMOS transistors 14 and 16 . This condition ensures the latch will switch correctly in the direction imposed by the biasing of the latches with V R at the end of the precharge operation. If V R is negative, i.e., V 2 <V 1 , then V 2 will go low while V 1 will go high. If V R is positive, i.e., V 2 >V 1 , then V 2 will go high while V 1 goes low.
[0031] In order to be correctly sensed by the sense circuitry, the memory cell current should meet certain conditions. Given the practice condition for a latch switching operation (as discussed above) |V R |≧3·σ VTN , the following is obtained: 3·σ VTN <V Rinit −ƒ·Icell<−3·σ VTN , resulting in the following conditions for the memory cell current:
[0000]
Condition
1
:
Icell
>
3
σ
VTN
+
V
Rinit
f
=
I
L
1
Condition
2
:
Icell
<
3
σ
VTN
-
V
Rinit
f
=
I
L
2
[0000] If condition 1 is fulfilled, V 2 will go low when the latch is activated. If condition 2 is fulfilled, the latch will switch in the opposite direction and V 2 will go high. As shown in FIG. 6 , in some embodiments, if the memory cell current is between I L1 and I L2 , the latch output is unknown due to mismatching devices.
[0032] With regard to FIG. 2 , identical structures are on the output nodes V 1 58 and V 2 22 to match or closely match the capacitances on these nodes 58 , 22 . The voltage on node V 2 22 is transferred to the dout node 88 once the sensing operation has been performed (i.e., the latch switching operation has occurred). Switch 74 is activated by the latchd and latchdn signals. The signal passing through switch 74 is inverted 66 and before the output signal is transferred to the dout node 88 . As has been discussed above, the output switches 74 , 76 are off during the sensing operation. Data transfer to the output node 88 occurs when the latchd and latchdn signals activate the output switches 74 , 76 (for example, latchd is set to “1” while latchdn is set to “0”).
[0033] Sequencing circuitry is shown in FIG. 7 . The atd signal controls the bit and word line discharge circuitry used for initialization (block 106 ). The precharge circuitry then precharges the dummy bit line and dummy word line as well as the bit line and word line (block 108 ). once the dummy bit line and dummy word line are precharged, the signals EndprechW) and StopprechB 1 are set to high and the reset signal is set to low. The output of the register goes low and NAND cell 124 sets signal prechB 1 high to stop precharge of the bitline (block 110 ). The precharge operation is turned off when the EndprechW 1 signal goes high (block 112 ). A NAND cell 122 is used to activate the circuitry to generate delays. A first delay signal d 1 is asserted on a delay line (block 118 ) between the end of the precharging operation and the latch signal going high (block 114 ), at which time data is read. A second delay signal d 2 is asserted on another delay line (block 120 ) before the latch d signal goes high (block 116 ), at which time data is valid. In one embodiment, the register is a D flip flop with clear (the register is clear when the reset signal is low). The delay circuits are inverters with capacitors.
[0034] The sense circuit described above is able to operate at very low supply voltages (for instance, 1.2 V, though other voltages (greater and smaller than 1.2 V) may be used). The circuit also provides for perfect control of the latch DC biasing conditions before latch activation. The circuit also consumes little power (for example, 15 μA per sense in 0.13 μm technology has been achieved). The circuitry is self-synchronized and there is no need for an external clock.
[0035] The sense circuit described above may have different configurations in other embodiments. For instance, dummy bit lines and dummy word lines are not required. Instead of a dummy bit line, a capacitor nearly equal to the bit line capacitor can be used.
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A sense amplifier circuit and a method for reading a memory cell. A circuit comprises a first bit line associated with a memory cell. A first input of a latch is coupled to the first bit line and a second input of the latch is coupled to a second node. There is a means for biasing the first input and the second input of the latch to a differential voltage between the first node coupled to the first bitline and the second node. There is also a means for switching the latch according to memory cell current. There is also a means for producing an output signal indicating the direction of switch. A method of reading a memory cell comprises precharging a first bit line which is associated with a memory cell. The memory cell current is driven according to the programmed state of the memory cell. Latch circuitry is biased based on a differential voltage between a first node coupled to the first bit line and a second node. The latch circuitry is then activated and the latch circuitry switched according to the memory cell current. An output signal indicating the direction of the latch circuitry's switch is then produced.
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FIELD OF THE INVENTION
The present invention relates to a weaving-machine auxiliary nozzle which is configured as a hollow needle which, in a wall adjoining a closed tip, includes one or several outflow apertures that, when the auxiliary nozzle is mounted on the weaving machine, is directed towards a filling-yarn insertion duct.
BACKGROUND OF THE INVENTION
a. Description of Related Art
Such auxiliary nozzles are known from U.S. Pat. No. 5,020,574. They enhance filling insertion into a weaving machine's shed. Several such auxiliary nozzles are distributed for that purpose across the width of the batten and they each supply a flow of fluid supporting the motion of a filling yarn blown into a filling yarn insertion duct associated with the batten. The auxiliary nozzles are arrayed in such a way that blow aperture(s) disposed in a wall underneath the tip shall point in a given direction toward the upper wall and the back wall of the filling insertion duct. The fluid streams from the blow apertures flow substantially in the longitudinal direction of the filling insertion duct and include an upward and oblique component.
During weaving the auxiliary nozzles move through the lower plane of warps into the shed at each filling insertion. It was observed that warps consisting of several thin and individual filaments and exhibiting only a slight twist will fray/unravel at those sites where the auxiliary nozzles pass through the plane of the warps in one direction into and then back out of the shed. Such fraying/unraveling arises foremost in filament yarns wherein thin synthetic filaments substantially run parallel to one another and are welded to each other at regular spacings. In such cases the fabric has an appearance at the sites where the auxiliary nozzles move through the lower warp plane that differs from the appearance of the remaining fabric. These warps are bulkier in the region of the auxiliary nozzles than the remaining warps because these thin filaments no longer are rigorously configured next to each other.
b. Summary of the Invention
It is the objective of the present invention to design an auxiliary nozzle of the above described kind so that the danger of damaging the warps is reduced.
This goal is attained in that in its tip area the hollow needle includes a bulge pointing towards the reed when the auxiliary nozzle is mounted on the weaving machine.
The auxiliary nozzle of the invention not only reduces the danger of finding its way between the individual filaments of a warp, but also precludes the fluid flow(s) through the outflow aperture(s) from adversely affecting the warps.
To facilitate moving the auxiliary nozzle through the lower plane of warps into and out of the shed, the invention appropriately assures that the bulge's walls shall continuously adjoin the hollow needle's walls. As a further advantage, the bulge includes a wall which is substantially flush with the wall that contains the outflow aperture(s).
In a further embodiment of the invention, the hollow needle's inner volume expands into the bulge zone. In this case the cross-section of the inner volume may be decreased in the related perpendicular direction. As a result a further advantageous design allows increasing the thickness of at least the wall comprising the outflow apertures. This wall thickness may be increased without thereby decreasing the flow cross-section towards the outflow apertures and increasing the flow impedance, because the expansion of the inner volume increasing the flow cross-section in the bulge zone.
Thereupon, in a further embodiment of the invention, the outflow aperture(s) are designed as nozzles. Such nozzle allows improved collimation and directionality of the fluid jet(s), and as a result such jets will be more effective in driving a filling.
Moreover the bulge makes it also possible to place the cross-sectional surface of the outflow aperture(s) required for the given quantity of fluid closer to the tip of the hollow needle. This feature offers the advantage that the outflow aperture(s) when entering a shed will move earlier past the warps and when leaving the shed will move past them later, and consequently the time interval within which a fluid flow is supplied by the auxiliary nozzles can be enlarged without thereby affecting the warps.
In a further embodiment of the invention, the hollow needle's tip comprises a substantially straight top edge extending as far as the bulge zone. Advantageously the top edge subtends an angle of 70 to 110° with the hollow needle's longitudinal axis.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and features of the invention are illustrated in the following embodiment shown in the drawings and in the sub-claims.
FIG. 1 schematically shows part of an airjet loom with several auxiliary nozzles,
FIG. 2 is a section along line II—II, with the reed and the auxiliary nozzles in their rearmost positions,
FIG. 3 is a section similar to that of FIG. 2 during the batten motion when the auxiliary nozzle(s) move(s) through a lower warp plane,
FIG. 4 is an enlarged sideview of an auxiliary nozzle of the invention,
FIG. 5 is a section along line V—V of FIG. 4,
FIG. 6 is a section along line VI—VI of FIG. 5,
FIG. 7 is a section along line VII—VII of FIG. 3,
FIG. 8 is a section similar to that of FIG. 2 of a modified embodiment,
FIG. 9 is a section corresponding to that of FIG. 3 of the embodiment mode of FIG. 8,
FIG. 10 is an enlarged elevation of the auxiliary nozzle of FIGS. 8 and 9,
FIG. 11 is an enlarged section similar to that of FIG. 6 of the auxiliary nozzle of FIGS. 8 and 9,
FIG. 12 is a view of a modified embodiment of an auxiliary nozzle,
FIG. 13 is a further embodiment of an auxiliary nozzle,
FIG. 14 is a longitudinal section of the auxiliary nozzle of FIG. 13, and
FIG. 15 shows yet another embodiment of an auxiliary nozzle.
DETAILED DESCRIPTION
The weaving machine shown in FIG. 1 comprises a reed 3 consisting of a plurality of dents each fitted with a recess so as to constitute a U-shaped filling insertion duct 4 . Fillings 1 , 2 are inserted into this filling insertion duct 4 in a shed 21 defined by warps configured in an upper and a lower plane of warps 17 , 18 resp. as shown in FIGS. 2 and 3. The fillings 1 and 2 resp. are blown-in by main blowing nozzles 5 and 6 . Further transportation of the fillings 1 or 2 in the filling insertion duct 4 is supported by airjets 7 produced by auxiliary nozzles 8 . The airjets 7 are directed substantially in the longitudinal direction of the filling insertion duct 4 transversely of the nozzles but have a direction component which is oblique and slightly upward and which points toward the upper wall 15 and the back wall of the filling insertion duct 4 and onto the fillings 1 , 2 . The reed 3 , the main blow nozzles 5 , 6 and the supports 9 of the auxiliary nozzles 8 are mounted on a cross-sectionally shaped batten bar 10 of a batten in the manner illustratively known from U.S. Pat. No. 5,020,574. This batten bar 10 illustratively is affixed by batten supports to a batten shaft (not shown) driven in reciprocating motion.
As shown in FIGS. 2 and 3, a shed 21 consists of an upper plane of warps 17 and a lower plane of warps 18 which converge into the beatup line 19 where the fillings are beaten by the reed 3 into a fabric 20 . A filling is beaten by the back wall 16 of the U-shaped filling insertion duct 4 , said back wall belonging to the central part 24 of said reed. The upper segment 23 of the dents of the reed 3 constitutes an upper wall 15 of the guide duct 4 . The lower wall 14 of the guide duct 4 is constituted of the lower portion 22 of the dents of the reed 3 .
As shown in FIGS. 2 through 6, the auxiliary nozzle 8 is configured like a hollow needle 11 which is fitted near its tip 12 with an outflow aperture 25 in a sidewall 26 . As shown by FIG. 4, the outflow aperture 25 comprises a plurality of smaller apertures. The hollow needle 11 of the auxiliary nozzle 8 includes, in the vicinity of the tip 12 , a single lateral bulge 13 which faces the reed 3 when the auxiliary nozzle 8 is mounted on the batten. The bulge 13 extends generally perpendicular to the direction of the outflow nozzles and comprises a sidewall 27 constituting an extension of the sidewall 26 of the hollow needle 11 fitted with the outflow aperture 25 . The bulge 13 is located near the lower portion 22 of the reed 3 in the region of the lower wall 14 of the filling insertion duct 4 . The distance D between the bulge 13 and the lower portion 22 of the reed illustratively is less than 3 mm.
The auxiliary nozzle 8 comprises a top edge 28 extending up to the region of the bulge 13 . This top edge 28 is substantially straight and by means of roundings of comparatively large radii adjoins the hollow needle 11 and the bulge 13 . The highest point 30 of the tip 12 of the hollow needle 11 is situated in the region of the bulge 13 . As shown by FIGS. 2 and 3, the top edge 28 of the auxiliary nozzle 8 when mounted on said reed extends approximately tangentially to a circle 31 centered on the axis of the batten shaft. In the embodiment of FIGS. 2 through 6, the top edge 28 extends at an angle of about 110° relative to the longitudinal axis 32 of the auxiliary nozzle 8 . The top edge 28 may extend at angles of 70 to 110° preferably relative to the axis 32 .
By means of the batten motion and at each filling insertion, the auxiliary nozzles 8 are moved between the warps of the warp plane 18 into the shed 21 and following filling beatup are then moved again through the warp plane 18 out of the shed 21 . The auxiliary nozzles 8 move from the dashed-line position shown in FIG. 3 into the position shown in FIG. 2 and then back. Said nozzles assume intermediate positions during this motion as indicated for instance in FIG. 3 . When the tips 12 of the auxiliary nozzles 8 are moving through the lower warp plane 18 , the top edges 28 of the auxiliary nozzles 8 will subtend an angle H with said plane 18 . This angle H is defined in such a way that the highest point 30 on the top edge 28 of the bulge 13 situated near the reed 3 shall first make contact with said lower warp plane 18 . It must be borne in mind in this respect that the warp planes 17 and 18 have moved apart so they attain the position shown in FIG. 2 when the auxiliary nozzles 8 penetrate the lower warp plane 18 .
As shown in FIG. 7, the warps guided through the dents 38 of the reed 3 are deflected by the auxiliary nozzle 8 as this nozzle moves through the warps of the lower warp plane 18 . These warps then are stretched. In the process, the warps 18 rest against the sidewalls 27 , 33 of the bulge 13 and against the dents 38 of the reed 3 . As a result, the warps 18 near the blow aperture 25 of the auxiliary nozzles 8 shall be tensioned. As a result of tensioning the warps formed of several adjacent, thin filaments, these filaments therefore shall be slightly compressed against one another. Consequently the airjet 7 from the auxiliary nozzles 8 is less able to penetrate between the individual filaments. Hence warp fraying/unraveling will be reduced.
As shown by FIGS. 4 and 5, the cross-section of the inner volume 36 of the hollow needle 11 of the auxiliary nozzle 8 expands at the level of the bulge 13 (direction of arrow 37 in FIG. 5) on account of this bulge 13 .
In the embodiment mode shown in FIGS. 8 through 11, the auxiliary nozzle 8 also is fitted with lateral bulge 13 pointing toward the reed 3 . The top edge 28 extends over the hollow needle's tip and across the bulge 13 and subtends an angle of about 90° with the longitudinal axis 32 of the needle 11 . When entering the shed through the lower warp plane 18 , the top edge 28 will subtend an angle H with this lower plane 18 , this angle H being such that the portion of the top edge 28 facing the reed 3 is the last to make contact with the warps of the lower warp plane 18 and the portion of the top edge 28 away from the reed 3 is the first one. While the auxiliary nozzle 8 is moving through the warp plane 18 , then, as shown in FIG. 10, the top edge 28 will guide the weld nodes 35 which connect substantially mutually parallel yarn filaments of a warp thread of the lower warp plane 18 to each other. A weld node 35 is able to slide over the top edge 28 of the auxiliary nozzle 8 moving into the shed and to assume the position indicated in FIG. 10 in dashed lines. Because of the substantial length of the top edge 28 and on account of the angle H, the auxiliary nozzle 8 is precluded from inserting itself between the individual filaments of a warp thread at the lower warp plane 18 . The top edge 28 is of such a length that the auxiliary nozzle 8 , which moves jointly with the batten, cannot penetrate a warp thread of the lower warp plane 18 between two consecutive weld nodes 35 . As a result the motion of the auxiliary nozzles 8 cannot rip open the weld nodes 35 .
The angle subtended between the top edge 28 and the longitudinal axis 32 and/or the geometry of the auxiliary nozzles 8 formed as hollow needles 11 shall be matched to the material of the warps being processed in such a way that warps shall not be damaged when the shed is being entered, for instance such that they shall neither fray nor unravel. Preferably this angle shall be of a magnitude between 70 and 110°.
The cross-section of the interior volume 36 of the hollow needle 11 of the auxiliary nozzle 8 is less where the bulge 13 begins (direction of arrow 34 in FIG. 11) than in the previous segment 39 . In the region of the outflow aperture 25 , the wall thickness of the auxiliary nozzle 8 is larger than in the remaining region of the tip 12 . The larger wall thickness makes it possible to better guide the fluid jet in the individual apertures of the outflow aperture, because the length of said apertures being greater. In this manner too, there is less danger that an airjet 7 (FIG. 1) shall damage the warps.
The interior volume 36 within the auxiliary nozzle 8 can easily be configured for advantageous flow, that is, to support an airjet 7 out of the outflow aperture 25 . Illustratively the inner bead 29 shown in FIG. 11 may be used for that purpose, which improves deflecting the fluid flow toward the outflow aperture 25 .
In the embodiment mode of FIG. 12, the individual apertures of the outflow aperture 25 are situated closer to the top edge 28 of the auxiliary nozzle 8 and are not distributed on a circular surface, but are configured in three superposed rows. In this design the individual apertures also extend in the zone of the bulge 13 and as a result the same number of individual apertures (in this illustrative embodiment there are nineteen individual apertures) may be confined more closely to the top edge 28 , that is, the same total cross-section may be attained for the outflow aperture 25 . Because this outflow aperture 25 in this embodiment fully crosses the lower warp plane 18 earlier, the fluid outflow may begin earlier. Because in the corresponding opposite motion the outflow aperture 25 moves later through the lower warp plane 18 out of the shed, the fluid flow out of the auxiliary nozzle 8 may be extended.
As regards the embodiment of FIGS. 13 and 14, the outflow aperture 25 has the shape of a slotted nozzle extending substantially parallel to the top edge 28 of the auxiliary nozzle 8 . As shown in FIG. 14, this outflow aperture 25 is relatively long and furthermore has the geometry of a nozzle 40 , in particular that of a Laval nozzle. In this manner a strip-like supersonic airjet 7 may be attained at the outlet of the nozzle aperture 25 . Such a strip-like, collimated airjet only slightly loads the nearby warps of the lower warp plane 18 and the danger of these warps fraying/unraveling shall be reduced. Moreover the collimated airjet 7 may forcefully drive a filling 1 or 2 . Also the auxiliary nozzle 8 of FIGS. 13 and 14 offers the advantages of the embodiment of FIG. 12 .
The embodiment of FIG. 15 is similar to that of FIG. 12 . However the outflow aperture 25 includes only of a small number of individual apertures, in this example only three apertures of different flow cross-sections. The apertures' flow cross-sections are smallest in the region of the bulge 13 and largest at the locations farthest from said bulge.
The auxiliary nozzle 8 of the invention is not limited to blowing an airjet 7 , but instead it may also be used with another fluid moving a filling. Such a fluid illustratively may be a liquid such as water, as a result of which a liquid jet would be directed on the wefts. Again a gas may be used as the fluid, or a gas containing a liquid spray or fog, for instance a gas holding atomized water.
The invention is not limited to the above described embodiments. Instead combinations of those embodiments are feasible, for instance the auxiliary nozzle 8 of FIG. 6 may comprise an inner space of the auxiliary nozzle 8 as shown in FIG. 11 . The scope of protection is solely determined by the patent claims.
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The invention relates to an airjet weaving-machine auxiliary nozzle ( 8 ) in the form of a hollow needle ( 11 ) having a closed tip ( 12 ), the auxiliary nozzle having a bulge at its distal end extending towards one side only of the nozzle centerline, such that the bulge extends towards a reed of a weaving machine in which the nozzle is installed relative to the centerline.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent Application No. 61/899,918 filed Nov. 5, 2013, the disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to lint collection systems for laundry dryers and, more particularly, to an automatic lint filter cleaning and lint collection system for laundry dryers.
BACKGROUND OF THE INVENTION
[0003] Laundry dryers typically have a rotatable drum that tumbles laundry as it is dried. A blower motor pulls heated air through the tumbling laundry to remove moisture from the laundry. As the air is drawn through the laundry, it picks up lint. The air/lint mixture is then pulled through a lint filter to remove the lint and then the filtered air can either be recycled back into the dryer air flow system or exhausted to the outside of the dryer. The lint filter must be cleaned frequently to prevent lint buildup and interference with proper air flow and dryer function. Lint filters are typically removed by hand and cleaned by a user, preferably after each drying cycle.
[0004] What is needed is an automatic lint filter cleaning and lint collection system to insure proper lint filter cleaning as well as to avoid the inconvenience to users of frequently cleaning lint filters.
SUMMARY OF THE INVENTION
[0005] The present invention comprises an automatic lint filter cleaning and lint collection apparatus and method for laundry dryers. The preferred lint filter cleaning and lint collection apparatus comprises an apparatus housing, a lint filter pivot chamber formed in an upper portion of the apparatus housing, a lint collection chamber formed in a lower portion of the apparatus housing below the pivot chamber, a lint filter housing pivotably mounted within the apparatus housing between the pivot chamber and the collection chamber, a lint filter secured within the filter housing, and a flange formed along an internal surface of the apparatus housing between the pivot chamber and the collection chamber, wherein the filter housing is biased into abutment with the flange. The preferred apparatus further comprises a lint collection container, a pipe connecting the lint collection chamber and the lint collection container, an auger rotatably mounted within the collection chamber, and a drive assembly operably connected to the lint filter housing and the auger. The drive assembly is operable to pivot the filter housing within the pivot chamber and away from the flange. The drive assembly is further operable to release the filter housing after the filter housing has been pivoted away from the flange such that the filter housing forcibly returns into abutment with the flange, causing the lint filter to release lint adhered thereto into the collection chamber. The drive assembly is further operable to rotate the auger and the auger is operable to move lint from the collection chamber, through the pipe, and into the collection container as the auger rotates. The lint in the collection container can be discarded when the collection container is full.
[0006] These and other features of the invention will become apparent from the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic view showing a typical prior art dryer system.
[0008] FIG. 2 is a schematic view showing the dryer system of the present invention.
[0009] FIG. 3 is a partially exploded front perspective view showing the lint filter cleaning and collection system of the present invention.
[0010] FIG. 4 is a rear perspective view showing the lint filter cleaning and collection system of the present invention.
[0011] FIG. 5 is a top plan view, partially in section, showing the lint filter cleaning and collection system of the present invention.
[0012] FIG. 6 is a side elevation view, partially in section, showing the lint filter cleaning and collection system of the present invention.
[0013] FIG. 7 is an exploded rear perspective view of the drive mechanism of the present invention.
[0014] FIG. 8 is an exploded front perspective view of the drive mechanism of the present invention.
[0015] FIG. 9 is side sectional view of the drive mechanism of the present invention.
[0016] FIG. 10 shows the lint filter housing in the home position.
[0017] FIG. 11 shows the lint filter housing in a partially raised position.
[0018] FIG. 12 shows the lint filter housing in a fully raised position.
[0019] FIG. 13 shows the lint filter housing returning to the home position.
DETAILED DESCRIPTION OF THE INVENTION
[0020] In FIG. 1 , a typical prior art dryer system is schematically shown, wherein the dryer 10 includes a rotatable drum 11 , an air conduit 12 having a hand removable lint filter (not shown) secured therein, a blower motor 13 , and an air exhaust conduit 14 . The blower motor 13 pulls heated air through the rotatable drum 11 , through the air conduit 12 and lint filter, and then forces the air through the air exhaust conduit 14 to the outside of the dryer. The direction of air flow is indicated by the arrows.
[0021] The preferred embodiment of the present invention is shown in FIGS. 2-13 . In FIG. 2 , the invention is schematically shown. In FIGS. 3-13 , detailed views of the lint filter cleaning and lint collection apparatus 25 and its operation are shown. Referring to FIG. 2 , the dryer 20 includes a rotatable drum 21 , an air conduit 22 , a blower motor 23 , an air exhaust conduit 24 , and an automatic lint filter cleaning and lint collection apparatus 25 , or “lint collection apparatus”. The blower motor 23 pulls heated air through the rotatable drum 21 , through the air conduit 22 , through the lint collection apparatus 25 , and then forces the air through the air exhaust conduit 24 to the outside of the dryer. The direction of air flow is indicated by the arrows.
[0022] Referring to FIGS. 3-13 , air from the drum 21 preferably flows through an air inlet 31 into a first air chamber 32 , downwards through a first opening 33 into a lint collection chamber 34 , upwards through a lint filter 40 into a lint filter pivot chamber 36 , through a second opening 37 into a second air chamber 38 , and out of the apparatus 25 through an air outlet 39 . The lint filter 40 is secured within a pivotable lint filter housing 41 operable to pivot within the lint filter pivot chamber 36 . A flange 42 forms a perimeter along an inner surface of the apparatus 25 between the pivot chamber 36 and the collection chamber 34 , wherein the lint filter housing 41 abuts the flange 42 when the filter housing 41 is in a substantially horizontal or “home” position. The filter housing 41 includes a pivot arm 43 operably connected to a drive mechanism 70 and a spring arm 44 operably connected to a spring 46 . The spring first end 47 is preferably attached to the spring arm 44 and the spring second end 48 is preferably attached to the pivot chamber 36 housing such that the filter housing 41 is biased against the flange 42 . The spring 46 can be any type of spring suitable to bias the filter housing 41 against the flange 42 , although a compression spring is preferred.
[0023] The bottom of the lint collection chamber 34 forms a tapering hopper 35 to collect lint 50 . A rotatable auger 51 is mounted within the hopper 35 and extends through a short pipe 61 into a lint collection box 62 through a hole 63 therein. The lint collection box 62 is removably located within a collection box chamber 64 . A lint collection bag 66 is preferably removably securable within the collection box 62 . The collection bag 66 preferably comprises an air impermeable plastic. The collection bag 66 is secured within the collection box 62 such that the bag opening 67 aligns with the collection box hole 63 . The collection box 62 is insertable within the collection box chamber 64 such that the short pipe 61 extends through the collection box hole 63 and collection bag opening 67 into the collection bag 66 , thereby reversibly securing the collection bag 66 to the short pipe 61 . An airtight seal is formed between the collection bag 66 and the short pipe 61 . The inside surface of the short pipe 61 preferably includes a helical protrusion 68 (see FIG. 6 ) that enhances transfer of lint 50 from the hopper 35 through the pipe 61 and into the collection box 62 , described in greater detail below.
[0024] The auger 51 comprises a shaft 52 having a helical flange 53 . The shaft 52 has a proximal end 55 that extends into the collection box 62 and a distal end 56 that is secured to the drive mechanism 70 . The outside diameter of the helical flange 53 (flight outside diameter) decreases from the distal end 57 of the flight length towards the proximal end 58 of the flight length such that the helical flange 53 has a distal portion outside diameter 54 a that is greater in the hopper 35 and a proximal portion outside diameter 54 b that is reduced in the short pipe 61 (see FIGS. 5 and 6 ). Further, the distance between the adjacent helical revolutions (pitch) decreases from the distal end 57 of the flight length towards the proximal end 58 of the flight length such that the pitch is greater in the hopper 35 and reduced in the short pipe 61 (see FIGS. 5 and 6 ). This auger design enhances transfer of lint 50 from the hopper 35 into the collection box 62 . The helical protrusion 68 along the inside surface of the short pipe 61 , if present, cooperates with the above described auger design to further enhance transfer of lint 50 from the hopper 35 into the collection box 62 . The helix direction of the auger helical flange 53 is preferably opposite to the helix direction of the short pipe helical protrusion 68 . Thus, if the auger helical flange 53 is a right-handed helix (as shown), the short pipe helical protrusion 68 is preferably a left-handed helix (as shown). The hopper 35 has a bottom end that forms an elongated channel that is slightly wider than the auger 51 and extends from the distal end 57 of the flight length to the short pipe 61 entrance. The bottom surface of the hopper 35 preferably has a distal segment 59 a immediately subjacent the auger flight length distal end 57 and a recessed proximal segment 59 b that slopes upward from the distal segment 59 a to the short pipe 61 entrance, best seen in FIG. 6 . The recessed proximal segment 59 b provides space for the lint to collect and the upward slope enhances the transfer of lint 50 from the hopper 35 into the short pipe 61 .
[0025] The drive mechanism 70 comprises a drive motor 71 that drives a drive shaft 72 and drive wheel 73 , a drive belt 74 , and a drive pulley 80 . The drive pulley 80 is mounted for independent rotation about the auger shaft 52 . The drive pulley 80 has a spring 81 and a pin (detent) 82 a , 82 b secured within a recess 83 on each side so that each detent 82 a , 82 b is operable to extend outward from the drive pulley surface 84 . A proximal detent 82 a is located on a proximal side 87 of the drive pulley 80 and a distal detent 82 b is located on a distal side 86 of the drive pulley 80 . An auger drive wheel 90 is preferably mounted adjacent the distal side 86 of the drive pulley 80 , wherein the auger drive wheel 90 is secured to the auger shaft distal end 56 for concomitant rotation. The auger drive wheel 90 includes a sloping arcuate slot 91 that has a first end 92 that is coplanar with the surface 93 of the auger drive wheel 90 and a second end 94 that is recessed below the auger drive wheel surface 93 . A filter housing drive wheel 100 is preferably mounted adjacent the proximal side 87 of the drive pulley 80 , wherein the filter housing drive wheel 100 is mounted for independent rotation about the auger shaft 52 . The filter housing drive wheel 100 includes a sloping arcuate slot 101 that has a first end 102 that is coplanar with the surface 103 of the filter housing drive wheel 100 and a second end 104 that is recessed below the filter housing drive wheel surface 103 . The filter housing drive wheel 100 has an eccentric cam 105 formed along a proximal side 106 thereof.
[0026] The drive mechanism 70 further comprises a crank arm 110 mounted adjacent the proximal side 106 of the filter housing drive wheel 100 . The crank arm 110 has a first end 111 having a hole 112 therein for receiving the eccentric cam 105 of the filter housing drive wheel 100 . The crank arm 110 has a second end 113 that is pivotably connected at a pivot point 114 to a first end 116 of a lift arm 115 . The lift arm 115 has a second end 117 that is pivotably connected to the pivot arm 43 of the filter housing 41 . A cam bar 120 extends from the apparatus 25 housing adjacent the lift arm 115 .
[0027] In operation, the dryer 20 is operated through a drying cycle. The lint filter 40 and filter housing 41 are in the home position shown in FIG. 10 . After a preset delay at the end of the drying cycle to allow time for air flow to cease, the dryer 20 initiates a lint filter cleaning cycle and the drive mechanism 70 is actuated to clean the lint filter 40 . The drive motor 71 is actuated to rotate the drive wheel 73 in a first direction (e.g. clockwise) which causes the drive pulley 80 to rotate in a first direction (e.g. clockwise) by operation of the drive belt 74 . As the drive pulley 80 rotates in the first direction, the spring-actuated proximal detent 82 a will slide within the sloping arcuate slot 101 in the filter housing drive wheel 100 until it engages the recessed second end 104 of the arcuate slot 101 , after which, the proximal detent 82 a will force the filter housing drive wheel 100 to rotate in the first direction concurrently therewith. When the drive pulley 80 is rotating in the first direction, the distal detent 82 b slides within the sloping arcuate slot 91 of the auger drive wheel 90 but does not engage the auger drive wheel 90 because of the direction of rotation within the arcuate slot 91 . As the filter housing drive wheel 100 rotates in the first direction, the eccentric cam 105 urges the crank arm 110 angularly upwards which, in turn, urges the lift arm 115 angularly upwards, as shown in FIGS. 11 and 12 . As the lift arm 115 moves upwards, it transmits lifting force to the pivot arm 43 which pivots the filter housing 41 upwards within the pivot chamber 36 . The maximum angle of the filter housing 41 relative to the flange 42 is between 30 to 90 degrees, most preferably 75 degrees. As the eccentric cam 105 reaches its uppermost limit, shown in FIG. 12 , the lift arm 115 engages the cam bar 120 , which urges the first end 116 of the lift arm 115 and the second end 113 of the crank arm 110 to pivot about pivot point 114 relative to each other and away from cam bar 120 . As this occurs, the upward lifting force of the lift arm 115 is suddenly released and the filter housing 41 rapidly falls back into abutment with the flange 42 (see FIG. 13 ). This “slapping” action dislodges lint adhered to the filter 40 , allowing the lint to fall into the hopper 35 . As the filter housing drive wheel 100 continues to rotate in the first direction, the eccentric cam 105 urges the crank arm 110 downward and the crank arm 110 and lift arm 115 pivot about pivot point 114 back into linear alignment with each other, as shown in FIG. 10 . The lint filter cleaning cycle can include one or more, preferably two, of these lint filter “slapping” cycles after each drying cycle.
[0028] After the lint filter cleaning cycle is completed, the dryer 20 initiates a lint collection cycle and the drive mechanism 70 is actuated to transfer lint from the hopper 35 to the collection box 62 . The drive motor 71 is actuated to rotate the drive wheel 73 in a second direction (e.g. counter-clockwise) which causes the drive pulley 80 to rotate in a second direction (e.g. counter-clockwise) by operation of the drive belt 74 . As the drive pulley 80 rotates in the second direction, the spring-actuated distal detent 82 b will slide within the sloping arcuate slot 91 in the auger drive wheel 90 until it engages the recessed second end 94 of the arcuate slot 91 , after which, the distal detent 82 b will force the auger drive wheel 90 to rotate in the second direction concurrently therewith. When the drive pulley 80 is rotating in the second direction, the proximal detent 82 a slides within the sloping arcuate slot 101 of the filter housing drive wheel 100 but does not engage the filter housing drive wheel 100 because of the direction of rotation within the arcuate slot 101 . As the auger drive wheel 90 rotates in the second direction, the auger 51 rotates therewith and the helical flange 53 advances lint 50 from the hopper 35 , through the short pipe 61 , and into the collection bag 66 within the collection box 62 . The lint collection cycle runs for a preset period of time, preferably 20 seconds. Once the lint collection cycle is completed, the dryer 20 will turn off. In an alternate embodiment, the auger 51 may include a reciprocating knife blade (not shown) mounted within the shaft 52 and extending slightly beyond the shaft surface to cut materials, such as hair, that wrap around the shaft 52 . The knife blade can be actuated to cycle back and forth after the auger 51 has ceased rotating.
[0029] The present invention cleans the lint filter 40 after each drying cycle and thus prevents lint buildup and interference with proper dryer function. Depending on the frequency of dryer use, the collection bag 66 should not need to be replaced for at least 6 months. A sensor detects when the collection bag 66 is full and activates a signal light on the dryer 20 . The collection box 62 can be removed by a user through an access panel in the dryer 20 , the collection bag 66 can be easily detached and removed from the collection box 62 , a replacement collection bag 66 can be secured within the collection box 62 , and the collection box 62 can be inserted back into the collection box chamber 64 to engage the short pipe 61 . A safety feature can be included that prevents operation of the dryer 20 when the collection bag 66 is full.
[0030] While the invention has been shown and described in some detail with reference to specific exemplary embodiments, there is no intention that the invention be limited to such detail. On the contrary, the invention is intended to include any alternative or equivalent embodiments that fall within the spirit and scope of the invention as described and claimed herein.
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An automatic lint filter cleaning and lint collection system for a laundry dryer. The apparatus comprises a lint filter pivot chamber, a lint collection chamber, a lint filter housing pivotably mounted between the pivot chamber and collection chamber, a flange between the pivot chamber and collection chamber wherein the filter housing is biased into abutment with the flange, a lint collection container, an auger rotatably mounted within the collection chamber, and a drive assembly operably connected to the lint filter housing and auger. The drive assembly is operable to pivot the filter housing away from the flange and then to release the filter housing such that the filter housing forcibly returns into abutment with the flange and thereby causes the lint filter to release lint into the collection chamber. The drive assembly is operable to rotate the auger and thereby move lint from the collection chamber into the collection container.
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BACKGROUND OF THE INVENTION
The flush toilet or urinal has been an important item of equipment in our daily living; for instance, each current urinal is commonly provided with an automatic flush device, which can sense when the urinal is being used by a person. If it senses a user using the same, the urinal will first discharge a small volume of water, and as soon as the user leaves it, a large volume of water will be discharged therefrom to clean any urine that might be left. However, while the conventional flush toilet or urinal can flush away the urine, it is unable to clean and remove the urine sediment or residue accumulated in the urinal; as a result, the urinal emits an undesired odor. Deodorant devices have been installed over or in the urinal for masking undesired odors. Although such urinal equipment can mask an undesired odor and provide a user with a fragrant atmosphere upon the urine being flushed, the urinal would still have an undesired urine sediment accumulation after a period time. Also, an undesired odor can still be generated to mix with the deodorant so as to produce a strange odor. In order to solve the aforesaid problem, it is necessary to have a person clean the urinal daily. Unfortunately, such a practice of cleaning a urinal can not be afforded by the average public, except by a corporation or the like. For a public flush toilet, such a practice would be expensive and therefore most often the public toilets and urinals are not cleaned with sufficient frequency
In view of the drawbacks of the conventional flush toilet or urinal which can only flush water and provide a fragrant odor, without cleaning and removing the urine sediment, the inventor has, through many years of experiences in designing and making such equipment, developed the present invention, i.e., a flush toilet or urinal with an antomatic sterilizing device.
SUMMARY OF THE INVENTION
The prime object of the present invention is to provide a flush toilet or urinal with an automatic sterilizing device, which can flush and sterilize a urinal simultaneously so as to clean any urine sediment that might be left therein.
In order to fulfil the aforesaid object, the present invention has a control circuit for controlling two stages of flushing water, and a sterilizing unit which includes a sterilizing liquid container and a liquid pump to control the discharging volume of the sterilizing liquid. The liquid pump is controlled with the control circuit to pump a suitable volume of sterilizing liquid to mix with the flush water to fulfil the flushing and sterilizing functions.
BRIEF DESCRIPTION OF THE DRAWINGS:
FIG. 1 is a perspective view of a flush toilet or urinal cleaning and sterilizing device according to the present invention.
FIG. 2 is a disassembled view of the embodiment according to the present invention.
FIG. 3 is an assembled view of the present invention, showing the housing part thereof being removed.
FIGS. 4A, B, and C illustrate the control circuits used in the present invention.
FIG. 5 is a block diagram, showing the flow chart of the control circuits used in the present invention.
DETAILED DESCRIPTION
Referring to FIGS. 1, 2 and 3, the flush toilet or urinal cleaning and sterilizing device according to the present invention comprises an outer body (10), a control circuit (20), and a sterilizing unit (40). The outer body (10) includes a housing part or hood 11 and a back board (12); the housing part (11) comprises a front wall and four perimeter edge walls that fit over the edges of back board 12. The housing (hood) has a small window (111) in the front thereof, fastening tongues (112) on its rear upper edge, and, a slot (113) and two screw holes (114) on its undersurface. The top edge of the back board (12) has a flange (121) to be mated with the fastening tongues (112) so as to facilitate assembly or disassembly of the back board (12) and the housing part (11) to each other, and to facilitate inspection and replacement of various parts inside the outer housing body. Along the upper edge of back board 12, a water proof rubber strip (115) is attached and against a wall "R" to prevent liquid from infiltrating into the space circumscribed by the housing part of the outer body (10) and the back board. The slot (113) is aligned with a cut out (122) under the back board. The upper edge of the back board (12) is provided with fastening holes (123) for receiving screw bolts "P" so as to fix the back board on a wall. A transformer seat (13) includes two opposite L-shaped brackets (131) each having a through hole (132) and a fixing plate (133) for detachably mounting a transformer (14) thereon. The transformer (14) has two lugs (141) on both sides thereof, each having a through hole (142) for receiving a screw (143) which passes through the through holes (132) and (142). The lugs (141) are to be mounted in the corresponding L-shaped brackets (131) to have the transformer (14) exactly mounted on the fixing plate (133), after which the transformer can be mounted on the back board (12). A circuit board seat (15) has two fastening holes (151) and two fixing pieces (152) spaced laterally apart for mounting a U-shaped circuit bracket (153). An ear at each edge of the bracket has a fastening hole (154) aligned with one of the fastening holes (151) for receiving a screw to fasten the U-shaped circuit bracket (153) on the back board. A sterilizing unit seat (16) includes a fastening hole (161) and a fixing plate (162) which has a recess portion (163) and two hooks (164).
As shown in FIGS. 4A, 4B and 4C, the control circuit (20) includes two PC (printed circuit) boards connected with a transformer (14). The two PC (printed circuit) boards are mounted on the U-shaped circuit bracket (153) (the circuit on the PC boards to be described later), and a sensor (155) is aligned with the small window (111) on the housing part (11).
The water supply unit (30) includes a solenoid valve (31) and a stop valve (32); the water inlet (321) of the stop valve (32) extends through a cut out (122) on the back board (12), for connection with a water pipe, not shown. The solenoid valve (31) extends directly above the slot (113) on the housing part (11), so that the valve liquid discharge outlet extends downwardly through the slot (113). One side of the water outlet has a tubular connector (311) that is adapted to telescopically connect with one end of a flow tube 423. The stop valve 32 is connected with the control circuit (20) to control the water volume through valve 31.
The sterilizing unit (40) includes a sterilizing liquid container (41) and a liquid pump (42); the liquid container (41) has a liquid inlet (411), through which the sterilizing liquid can be replenished, and a cap (401) with a vent (402). A fastening hole (161) in the sterilizing unit seat (16) is to coincide with a hole on a lug (412), which is to be fastened to the hole (161) by means of a screw. The bottom of the sterilizing liquid container (41) is to be mounted on the fixing plate (162) to have the recess portion (163) mated with a positioning lug (413) having a through hole (414) so as to have the container (41) mounted firmly on the fixing plate (162). The bottom of the container (41) has a groove (415), which is to be mated with the hooks (164) on the fixing plate (162). The liquid pump (42) has a connecting liquid inlet stub (421) to be inserted into the hole (414), whereby the pump is mounted on the front wall of the container. The liquid pump (42) has a sterilizing liquid outlet (422), that is connected to one end of a tube (423). The other end of tube 423 is connected with the connector (311) of the solenoid valve (30). The motor portion of the liquid pump (42) is electrically connected with the control circuit (20) via terminals accessible through the space above the pump, whereby the pump can be energized to generate a flow of the sterilizing liquid through tube 423.
Referring to FIGS. 4A, 4B, 4C and 5, the operation of the control circuit (20) is described as follows:
The sensor (155) can generate a signal by means of infra-red to scan a given range (a sensor circuit being shown in FIG. 4A); then, the micro-CPU (22) would judge whether there is a user within a given range. When the sensor has sensed a user standing in front of a urinal for four seconds, the sensor will send a signal (23) to the micro-CPU (22) (as shown in FIGS. 4B and 4C, the signal will be transmitted from P10 to transistor Q1 to have the relay switch Ry1 turned on) to have the solenoid valve (30) opened so as to provide a first flush for at least three seconds. As soon as the user leaves the urinal, the sensor has no signal sensed, but it will send a signal (24) to the micro-CPU (of which the circuit is shown in FIG. 4C; a signal will be sent, through P10, to the transistor Q1 to have the solenoid switch Ry1 turned on) 5 to have a solenoid valve opened to provide a second flush for at least eight seconds.
During the second flush period at the stage of about 6.5 seconds, the micro-CPU will generate a signal (25) (as shown in FIG. 4C, the signal will be sent from P12 to transistor Q3 to have a relay switch Ry3 turned on) to control the liquid pump (42) to run so as to pump a given volume of sterilizing liquid to flow through a tube (423) to the solenoid valve (30), where the sterilizing liquid and the flushing water will be mixed together before being discharged (the supplying time of the sterilizing liquid is about 0.5 second, while the flushing water is continuing, so as to let the sterilizing liquid have sufficient time to wash away the uring sediment until the end of eight seconds). Consequently, two functions, i.e., the water flushing and urine sediment washing can be done simultaneously and effectively.
The major feature of the present invention is that the sterilizing liquid container is controlled with the liquid pump for discharging a suitable volume of sterilizing liquid, and the control circuit can control the solenoid valve and the liquid pump to operate integrally. In real use, two functions of water flushing and urine sediment washing can be done simultaneously so as to improve the drawbacks of a conventional flush toilet or urinal relating to inadequate removal of urine sediment, and an undesired generation of odors.
In brief, the present invention can meet the object of the invention, and can eliminate the drawback of a conventional urinal that is often the subject of customer complaints.
It is understood that the attached drawings are used merely for describing an embodiment of the invention, and the modifications or changes can be made while still practicing the present invention.
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This invention provides a flush toilet with an automatic sterilizing device, which can discharge a small volume of flush water first upon sensing a user having used it, and then discharge a large volume with a given volume of sterilizing liquid so as to wash away any urine sediment in a urinal completely. The device comprises a control circuit to control a solenoid valve for controlling a given volume of flush water, and to control a sterilizing unit; the sterilizing unit includes a sterilizing liquid container which is controlled with a liquid pump to discharge liquid. The liquid pump is controlled with the control circuit. During the large volume discharge of water the liquid pump can pump and discharge a suitable volume of sterilizing liquid to mix with the flush water to wash and sterilize a urinal simultaneously.
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[0001] This invention relates to a lapping apparatus and a lapping method using the apparatus.
BACKGROUND OF INVENTION
[0002] Recently, hard disk drives are in use as standard memory for video equipment as well as for personal computers. The hard disk drive has a relatively higher storage capacity than other storage devices. Thus video equipment built with a hard disk drive enable the user to record video images for a longer period of time compared to conventional equipment. In television broadcasting, a shift to digital terrestrial broadcasting transmitting various types and a large amount of information to viewers has been announced. The video equipment built with a hard disk drive allows viewers to record information as much as they want, including information broadcast via digital terrestrial broadcasting.
[0003] In view of this trend, it is desired to increase the capacity of the hard disk drive much further. However, a technology known as longitudinal magnetic recording applied to current hard disk drives is unable to increase the capacity of the hard disk drive any more because the capacity has been improved to its limit.
[0004] Therefore a recording technology called perpendicular magnetic recording has been proposed recently to replace the longitudinal magnetic recording and further increase the capacity of the hard disk. The perpendicular recording method produces magnetic paths in a depth direction of a hard disk's recording surface, not in a parallel direction, thereby recording information. Consequently, a magnetic domain is narrowed so that the storage capability of the hard disk drive is increased further than that of the conventional one.
[0005] The hard disk drive adopting the longitudinal magnetic recording conventionally uses a combination-type magnetic head having both a writing element (for writing) and a reading element (for reading). This combination-type magnetic head is required to comply with a strict measurement precision of a distance between a head of the writing element or a head of the reading element and the hard disk's recording surface to write or read information onto or from the recording surface compatibly when built in the hard disk drive. Therefore the conventional combination-type magnetic head is processed and finished to predetermined height by lapping apparatus (refer to patent literature 1-5).
[0006] 1. Japanese Patent No. 3504105 (Counterpart of U.S. Pat. No. 5,899,793)
[0007] 2. Japanese Patent No. 3589546 (Counterpart of U.S. Pat. No. 6,196,897)
[0008] 3. Japanese Patent No. 3638815 (Counterpart of U.S. Pat. No. 6,315,636)
[0009] 4. Japanese Laid-open Patent Publication No. 2005-339781 (Counterpart of U.S. Pat. No. 6,884,148)
[0010] 5. Japanese Laid-open Patent Publication No. 2006-73088 (Counterpart of US Laid-open Patent Publication No. 2006-0044683)
[0011] Before describing the lapping method to fabricate the combination-type magnetic head to required dimension, a production process of the combination-type magnetic head will be explained briefly.
[0012] In fabricating the combination-type magnetic head, wafer processing is a first step. A plurality of the combination-type magnetic heads having both writing and reading elements are formed on a wafer two-dimensionally. Concurrently, resistance elements for the writing and reading elements called ELG are arranged in the vicinity of the heads (refer to patent literature 5). Since resistance values of these resistance elements vary in accordance with the amount of material removed by lapping, the lapping apparatus can perform proper lapping of the combination-type magnetic heads by reading the resistance values of these resistance elements.
[0013] During a second step, a plurality of the magnetic heads formed two-dimensionally are sliced to bars, thereby obtaining bar-shaped raw bars having the combination-type magnetic heads arranged in a row thereon. During a third step, each raw bar is affixed to the lapping apparatus, then a plurality of the magnetic heads arranged thereon are lapped to be finished all together. During lapping, each resistance value of the resistance elements for the reading or writing elements formed onto the wafer during the first processing are read by the lapping apparatus. When the resistance values read by the lapping apparatus reach a predetermined value, the lapping terminates as the writing and reading elements are processed to required specification. During a fourth step, the raw bars are diced to chips, thereby separating a plurality of the combination-type magnetic heads into individual heads.
[0014] A structure of the lapping apparatus for performing lapping of the raw bar as finishing will be described here.
[0015] FIGS. 1-5 show the structure of the lapping apparatus described in patent literature 1 and 2.
[0016] FIG. 1 shows lapping apparatus 1 having a lapping plate 10 and a lapping base 11 . FIG. 2 shows a structure of an adaptor 12 having an arm 120 supported at a support point 1210 positioned on the lapping base 11 shown in FIG. 1 and extending downwards from the end of the arm 120 to keep an under surface of the work (the word “work” used herein means the raw bar. Hereinafter the work is sometimes called raw bar 100 ) contacting a lapping surface of the lapping plate 10 . FIG. 3 shows an overhead view of the adapter 12 shown in FIGS. 1 and 2 . FIG. 4 shows a mechanism of the lapping apparatus 1 that is used for both an inclination correction and a load adjustment. FIG. 5 shows a bend correcting mechanism of the lapping apparatus 1 .
[0017] With reference to FIGS. 1-5 , the appearance of the lapping apparatus will be briefly described.
[0018] The lapping apparatus 1 shown in FIGS. 1-5 is a lapping apparatus to provide lapping processing to the raw bar 100 using the adaptor 12 and the lapping plate 10 having a lapping surface thereon which moves relative to the raw bar 100 . The lapping base 11 has bottom faces which can contact the lapping surface. The arm 120 is supported at the given support point 1210 (refer to FIG. 2 ) positioned on the lapping base 11 and extending in a horizontal direction from the support point 1210 and the supporting portion 121 extending downwards from the ends of the arm 120 to keep the raw bar 100 in contact with the lapping surface of the lapping plate 10 . The adapter 12 has a holder 1201 as shown in FIGS. 2 and 3 and the raw bar 100 is bonded onto the holder 1201 with an adhesive or other bond.
[0019] The supporting portion 121 has a pivotable mechanism to set the work 100 closer to or further away from the lapping plate 10 by pivoting the arm 120 . Before lapping, the arm 120 is pivoted upward and the raw bar 100 is bonded onto the holder 1201 attached to the adaptor 12 . Then the arm 120 is pivoted downward so that the raw bar 100 is set onto the lapping surface of the lapping plate 10 . Probes to read the resistance values of the resistance elements for the writing and reading elements are not illustrated, however, they are also attached onto the arm 120 .
[0020] With reference to FIGS. 1-5 , a structure of lapping apparatus 1 will be described.
[0021] The lapping apparatus 1 shown as in FIGS. 1-5 has the lapping base 11 fixed onto the lapping base 13 of the lapping apparatus as it pivots and oscillates freely (refer to FIG. 1 ) so that a degree of parallelization between the lapped surface of the raw bar 100 attached to the adaptor 12 and the lapping surface of the lapping plate 10 is maintained even where the lapping plate 10 oscillates to some degree when rotating.
[0022] The lapping apparatus 1 also has the load adjustment mechanism 14 to adjust lapping load onto the work 100 by applying the load from above the arm 120 for optimum lapping. When the lapping load is applied onto the work 100 via the adapter 12 by the load adjustment mechanism 14 , the lapped surface of the raw bar 100 contacts the lapping surface of the lapping plate 10 steadily and stable lapping is performed. The load adjustment mechanism 14 of the lapping apparatus 1 shown in FIGS. 1-5 can correct an inclination of the bar-shaped work 100 shown as in FIG. 3 in a longitudinal direction, i.e. a differential in height between right and left, by disposing three actuators 141 - 143 in an orthogonal direction to a direction that the arm 120 shown in FIGS. 1 and 2 extends as shown in FIG. 4 .
[0023] Having a regard to the characteristic of the raw bar 100 's bar like shape and certain length in a longitudinal direction shown as in FIG. 3 , the lapping apparatus 1 shown in FIG. 1 has the bend correction mechanism to correct wave undulation or bend resulting on the raw bar 100 .
[0024] The lapping apparatus 1 adopts a bend correction mechanism described in patent literature 3. FIGS. 5A and 5B are outline drawings of the bend correction mechanism disclosed in patent literature 3. The wave undulation and bend resulting on the lapped surface can be corrected by pressing holes 1201 h on the holder 1201 onto a fixture 36 , 38 .
[0025] The holder 1201 , bonded to the raw bar 100 , is attached to the end of the arm 120 extending from the end of the adaptor 12 equipped on the lapping apparatus having the foregoing mechanisms. The arm 120 pivots about the support portion 121 (refer to FIG. 2 ) downwards to set the raw bar 100 against the lapping surface of the lapping plate 10 .
[0026] Then the lapping load applied from above the arm 12 is adjusted by the load adjustment mechanism 14 , the lapped surface of the raw bar contacts the lapping surface of the lapping plate 10 and proper lapping is performed.
[0027] When the raw bar 100 is lapping with the rotating lapping plate 10 , the load adjustment mechanism 14 acts as the inclination correction mechanism and keeps the inclination of the raw bar 100 in the longitudinal direction parallel to the lapping surface of the lapping plate 10 . The bend correction mechanism corrects the wave undulation and bend of the raw bar 100 .
[0028] In addition to the load adjustment mechanism, the lapping base 11 is fixed onto the lapping base support portion 13 equipped on the lapping apparatus 1 as it rotates and oscillates freely as mentioned above so that the lapped surface of the work 100 is kept fitly touching the lapping plate 10 . Thus the lapped surface of the raw bar 100 can be maintained parallel to the lapping surface of the lapping plate 10 even where a cut plane of the raw bar 100 changes as lapping progresses and preferable lapping is performed.
[0029] The strict requirement of the dimension of the combination-type magnetic head mentioned above will be outlined here.
[0030] FIG. 6 is a pattern diagram showing a cross-section view of the raw bar in its shorter side.
[0031] FIG. 6 shows a structure of the combination-type magnetic head arranged within the raw bar 100 .
[0032] As shown in FIG. 6 , the writing and the reading elements are produced apart from each other and the resistance elements for the writing element WR are arranged in their vicinity. The resistance elements for the reading elements RD are arranged in their vicinity. However, these resistance elements are not shown in FIG. 6 . Lapping is performed in a direction shown by an arrow in FIG. 6 as resistance values of these resistance elements are read by the lapping apparatus 1 shown in FIGS. 1-5 . Hence dimensions called an MR-h or a neck height shown in FIG. 6 are adjusted within a required tolerance.
[0033] For the hard disk drive adopting the conventional longitudinal magnetic recording, since the reading element RD requires more strict dimension precision than that of the writing element WR, the lapping apparatus 1 reads the resistance value of the resistance element for the reading element and when the resistance value of the reading elements reaches the required value lapping terminates. Consequently, the neck height of the writing element in the combination-type magnetic head used for the hard disk drive adopting the longitudinal magnetic recording can be processed within the tolerance automatically when lapping terminates when the resistance value of the reading element reaches the required value. That is to say if the lapped surface of the combination magnetic head is beveled slightly in a latitudinal direction (a direction of the reading elements and writing element arranged in a row), it poses no problem for the combination-type magnetic head used for the hard disk drive adopting the longitudinal magnetic recording.
[0034] However, the perpendicular magnetic recording produces narrower magnetic domains as described above. Thus, not only the dimension of the reading element called the MR-h but also the dimension of the writing element called the neck height require stricter dimension precision.
[0035] As a result, it is not tolerable that the lap surface of the combination-type magnetic head shown as in FIG. 6 inclines to the lapping surface of the lapping plate in a latitudinal direction (the direction of the reading and writing elements arranged in a row) as in conventional manner. Thus the conventional lapping apparatus 1 as illustrated in FIGS. 1-5 cannot process the combination-type magnetic head used for the hard disk drive adopting perpendicular magnetic recording.
SUMMARY
[0036] In accordance with an aspect of an embodiment, a lapping apparatus for lapping a work includes a lapping plate having a lapping surface thereon that moves relative to the work. A lapping base has a bottom face contacting the lapping surface of the lapping plate. An adaptor having an arm supported at a given support point positioned on the lapping base extends in a horizontal direction from the support point and a supporting portion extends downwards from an end of the arm for holding an under surface of the work contacting the lapping surface. A tilt mechanism adjusts a contact angle of the work held by the supporting portion with the lapping surface of the lapping plate by adjusting a height of the support point positioned under the adaptor. In addition, in accordance with an aspect of another embodiment, a lapping method to lap a work including steps of contacting the work in which a plurality of heads are arranged along the longitudinal direction on a lapping surface of a lapping plate, rotating the lapping plate and lapping the work, and adjusting the contact angle of the lapped surface to the lapping surface about latitudinal direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1 is the perspective view of the conventional lapping apparatus.
[0038] FIG. 2 is the side view of the adapter of the conventional lapping apparatus.
[0039] FIG. 3 shows the holder and the raw bar bonded to the holder.
[0040] FIG. 4 shows the inclination correction mechanism.
[0041] FIGS. 5A and 5B show a detailed structure of the holder.
[0042] FIG. 6 shows a pattern diagram of the raw bar 100 's cross-section surface.
[0043] FIG. 7 shows a structures of a lapping base 11 a and an adopter 12 a in a lapping apparatus 1 a which is one embodiment of this invention.
[0044] FIG. 8 illustrates a structure of a control device 1000 a in the lapping apparatus 1 a.
[0045] FIG. 9 shows transition of the raw bar 100 's form during lapping performed by control sections in the control device 1000 a.
DETAILED DESCRIPTION
[0046] The embodiment of this invention will be described hereinafter.
[0047] FIG. 7 shows the structures of the lapping base 11 a and the adopter 12 a in the lapping apparatus 1 a which is one embodiment of this invention.
[0048] In addition to the conventional structure, a linearlinear actuator 130 is added to the supporting portion 121 as a tilt mechanism as shown in FIG. 7 .
[0049] The lapping base 11 a has a pivot PB supporting a support point 1210 a located under the adaptor 12 a . The tilt mechanism 130 is a linearlinear actuator having a body and a rod controlled its stroke length from the body by a control signal. The body of the linearlinear actuator 130 is embedded in an arm 120 a and the rod of the linearlinear actuator 130 touches and pushes the pivot PB with its head to adjust a height of the support point 1210 a finely. A stroke length of the linearlinear actuator is determined and fixed by using an optical flat method disclosed in patent literature 1 to parallelize the lapped surface of the raw bar 100 to the lapping plate before lapping. In this case, a linearlinear actuator MSD-23D23H10 (1 μm resolution, 10 mm stroke) manufactured by Chiba Seimitu Colo., LTD is used. When the support point 1201 a raises 200 μm from the predetermined height by protruding the rod of the linearlinear actuator 130 , a differential between the reading elements RD and the writing element WR arranged in a row in a latitudinal direction can be measured. The linearlinear actuator 130 can accommodate a stroke of its rod by 1 μm as a minimum resolution so that the differential in height between the reading elements RD and the writing element WR can be reduced to less than 0.05 nm.
[0050] In other words, the linearlinear actuator 130 having the structure shown in FIG. 7 can adjust the inclination in a latitudinal direction shown in FIG. 6 , thereby obtaining preferable parallelization of both the reading elements RD and writing element WR to the lapping surface.
[0051] FIG. 8 shows the structure of the control device 1000 a in the lapping apparatus 1 a.
[0052] The control device 1000 a shown in FIG. 8 has a CPU 1001 a . The CPU 1001 a drives each adjustment mechanism of each control section by executing processing programmed in a memory 1002 a in sequence.
[0053] The control device 1000 a shown in FIG. 8 has a common mechanism control section 1003 a therein to control a motor rotating the lapping plate 10 or to pour abrasive slurry onto the lapping plate 10 . This common mechanism control section 1003 a has a driver to drive a motor within a lapping plate rotating mechanism 170 and a drive section to drive an electromagnetic valve in a slurry switching mechanism 160 . When a command is sent from the CPU 1001 a to the driver or the drive section in the common mechanism control section 1003 a , the motor within the lapping plate rotating mechanism 170 a rotates the lapping plate 10 . At the same time, the electromagnetic valve within the slurry control device 160 opens to pour the slurry onto the lapping plate 10 and then lapping starts.
[0054] When the lapping plate 10 rotates and the lapping of the raw bar 100 starts, the resistance values of both reading elements and writing element within the raw bar 100 are read by an ELG resistance measure 150 under a control of the CPU 1001 a.
[0055] The CPU 1001 a executes commands to remove noise impeding the reading by a denoising section 1004 a in the lapping apparatus 1 a , reading correct resistance values of each resistance element on individual combination-type magnetic heads arranged in the raw bar one by one. Based on the result of the bar-shape forming, the CPU 1001 a command an inclination correction mechanism 14 via an inclination correction control section 1005 a to correct an inclination between the right and left ends of the raw bar in the longitudinal direction. The CPU 1001 a also commands the bend correcting mechanism (refer to FIGS. 5A and 5B ) via a bend control section 1007 a to correct the wave undulation or bend (which is equivalent to the word “bend” used herein) of the raw bar. In addition, the CP 1001 a commands the tilt mechanism 130 via a tilt mechanism control section 1006 a to correct the inclination of the raw bar in a latitudinal direction based on the result of foregoing processings. The slurry switching mechanism 160 and rotating mechanism 170 are controlled by common mechanism control section 1003 a.
[0056] FIG. 9 shows a raw bar's form transition during the lapping processing performed by each control section of the control device 100 a shown in FIG. 8 .
[0057] At the top right of FIG. 9 , a cross-section view of the work, i.e., the raw bar 100 , before the foregoing correcting processing is applied thereto by the inclination correcting mechanism 14 , the bend correction mechanism 110 (refer to FIGS. 5A and 5B ) or the tilt mechanism 130 controlled by each control section. Under the cross-section view, cross-section views of the work after any of foregoing correction is applied.
[0058] The form of the raw bar 100 before lapping is a trapezoid as shown at the top right. Whereas the raw bar is lapped to a symmetrical square and the lapped surface of the combination-type magnetic head having the reading elements RD and writing element WR is parallelized as much as possible to the lapping surface at the end of the processings.
[0059] With reference to the cross-section views of FIG. 9 from the top to bottom, the transition of the raw bar 100 's form will be explained.
[0060] First, the CPU 1001 a equipped in the control device 1000 a derives a bar like form from the resistance values of the resistance elements for the reading elements measured by the ELG resistance measure 150 and produces an image of the bar like shape shown at the top right. The illustration at the top right of FIG. 9 shows a form of the raw bar before lapping.
[0061] Recognizing the raw bar's form is as the trapezoid as shown at the top right of FIG. 9 , the control device 1000 a commands the inclination correction mechanism 14 to correct the inclination in the longitudinal direction via the inclination correction control section 1005 a . The control device 1000 a also commands the bend correction mechanism 110 (refer to FIGS. 5A and 5B ) to correct the wave undulation or bend via the bend control section 1007 a . Thus the lapped surface of the raw bar 100 becomes flatter than the surface before lapping shown as in the second cross-section view. Then the wave undulation or the bend is corrected by using only the bend correcting mechanism so that a given differential between the reading elements RD and the writing element WR is produced. When the differential becomes parallel, the tilt mechanism 130 adjusts the contact angle and then lapping is applied to parallelize both reading elements RD and the writing element WR to the lapping surface.
[0062] Conventional lapping processing terminates at a level shown as in the second cross-section view so that a required precision of the combination-type magnetic head for the hard disk drive adopting the perpendicular magnetic recording cannot be satisfied. However, an adoption of the tilt mechanism enables processing of the combination-type magnetic head for the hard disk drive adopting the perpendicular magnetic recording to a level shown at the bottom of FIG. 9 . Thus the combination-type magnetic head used in the hard disk drive adopting perpendicular magnetic recording is lapped precisely.
[0063] In this embodiment, a contact angle of the raw bar's lapped surface with the lapping surface can be adjusted gradually by 0.005 degrees at 3 second intervals by the tilt mechanism, through the linearlinear actuator 130 . Configuring the resolution to adjust the contact angle by micro-degrees enables lapping to parallelize both reading elements and writing element on the lapped surface as much as possible to the lapping surface of the lapping plate. In addition, this configuration to adjust the contact angle with the tilt mechanism also protects the lapping plate from suffering damage during lapping.
[0064] To protect the lapping plate from damage, it is effective to configure the load adjustment mechanism illustrated in FIG. 4 to reduce the load onto the work 100 before adjusting the contact angle by activating the tilt mechanism, i.e. the linearlinear actuator 130 . The lapping plate 10 can also be protected from damage by having the driver in the common mechanism control section 1003 a reduce the speed of the motor in the lapping plate rotating mechanism or stopping the motor when adjusting the contact angle by the tilt mechanism 130 .
[0065] The control section 1000 a has an operating section OP 1 as shown in FIG. 8 so that the contact angle can be better set to perform preferable lapping. Thus, where an operator decides to perform further finishing after a parallelization between the reading components RD and the writing components WR with a CCD camera, the operator can configure the contact angle by the operation section OP 1 to perform lapping as necessary by the lapping apparatus 1 .
[0066] Highly accurate lapping processing for the combination-type magnetic head used in the hard disk drive adopting the perpendicular magnetic recording can be realized in the manner described above.
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A lapping apparatus includes a lapping plate having a lapping surface thereon that moves relative to a work. The lapping apparatus can adjust an inclination of the work in a latitudinal direction, thereby obtained preferable parallelization of both a reading elements and writing element to the lapping surface. As a result, the lapping apparatus can provide magnetic heads suitable for the perpendicular recording.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of the prior filed, co-pending provisional application, Ser. No. 61/527,138, filed Aug. 25, 2011, incorporated by reference herein.
BACKGROUND OF THE INVENTION
This invention relates generally to transaction card holders and more particularly to an assembly for holding a transaction card, such as a gift card, upon a panel that pivots to be received within a pouch, pocket or sleeve.
Transaction cards, stored value cards, or gift cards, as they are commonly called based upon their intended use, have become popular gifts. Gift cards typically comprise a stored value card whereby a certain cash equivalent value is encoded upon a magnetic strip applied to the surface of the card. This stored value may be determined by the vendor prior to packaging and display for sale or, more commonly, is selected at the point of sale by the purchaser and loaded by the cashier using a magnetic card reader/writer. While popular, gift cards are typically provided with a generic and impersonal design, typically identifying the associated merchant for which the card may be used to purchase merchandise, and therefore are not personalized in view of the intended recipient.
Gift cards are often presented for sale on display racks in stores, each card or packet of cards being hung upon a display stand peg. A given area of a store will only support a certain number and size of display stands, given store traffic and other considerations, which makes allocation of display space an important marketing decision that may require selecting only certain high selling cards for display. Display of other items in the same store area will typically reduce the substantially finite space available for displaying gift cards and gift card packets.
In addition to the above considerations, gift card packets must fit within a set, allocated space in pre-existing displays. A gift card packet must not exceed 5.25″ tall and 4″ wide. These dimensions are an industry standard and are typically non-negotiable. In order to properly hang each gift card packet, the packet typically includes a J-hook hole (sombrero cut) with the exact dimensions of 1.875″ wide by 0.5″ high and be placed 0.1875″ from the top of the packet. Presently, the above requirements pertain to approximately 95% of all gift cards and gift card packets that are sold at retail.
What is needed, therefore, is a device that displays a gift card for purchase when hung upon a display rack within a predetermined and allotted display space but that provides an enhanced gifting assembly after purchase, removal of the header panel, and installation of the gift card within the assembly.
BRIEF DESCRIPTION OF THE INVENTION
The purpose of this invention is to provide an assembly for holding a transaction card, such as a gift card, upon a panel that pivots to be received within a pouch, pocket or sleeve. In certain embodiments of the invention, the holder elements are designed to mimic the overall shape and appearance of a price or sale tag commonly used to mark merchandise.
An embodiment of a gift card holder assembly according to the present invention may include an insert having means for receiving and retaining a transaction card thereupon, a sleeve including a pocket for receiving the insert, the insert pivotable from an open position for display and use to a closed position for transport and storage. A further embodiment of a pivotable gift card holder assembly according to the present invention may include an insert pivotally connected to a sleeve about a pivot point so that the insert and the sleeve may pivot relative to each other and about the pivot point, the insert including means for receiving and removably holding a transaction card upon the insert. When the assembly is in use, a transaction card is removeably mounted to the insert. The assembly may also include an aperture sized and located in the insert to allow indicia, such as a barcode or magnetic strip, on the surface of the card proximate the insert (typically the back surface of the card) to be viewed, scanned or otherwise accessed through the aperture. A header panel, including an aperture therein for receiving the peg of a display stand, may extend from an end distal to the pivot point of either the insert or the sleeve, or from a side of either the insert or sleeve. Typically, the header is joined to the other element of the assembly along a perforation line so that it may be removed prior to giving the assembly, including a transaction card held within, to a recipient.
Other advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example an embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation showing the swing tag card holder in an open disposition for display upon a merchant display rack.
FIG. 2 is a front elevation showing the swing tag card holder in an open disposition and with the header panel removed.
FIG. 3 is a front elevation showing the swing tag card holder insert pivoted to a partially closed position.
FIG. 4 is a front elevation showing the swing tag card holder insert pivoted to lie within the sleeve in a fully closed position.
FIG. 5 is a front elevation of the insert prior to assembly of the holder.
FIG. 6 is a plan view of material diecut to form the sleeve.
DETAILED DESCRIPTION
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.
With reference to the figures, FIGS. 1-6 are illustration of one or more embodiments of a swing tag card holder 100 for holding transaction cards, such as a gift card 105 . FIG. 1 is a front elevational view of the holder 100 showing the insert 110 in an upward, open disposition from the sleeve 115 , as would be typical for display of the holder 100 upon a merchant display rack. The insert 110 and sleeve 115 are pivotally connected about a pivot point 120 that is typically defined by an aperture 125 passing through proximate portions of the insert 110 and the sleeve 115 . The insert 110 and sleeve 115 are typically secured to one another at the pivot point 120 by a grommet (not shown) but may be secured using any device or structure that permits the insert 100 and sleeve 115 to pivot about the pivot point 120 .
The insert 110 typically includes a header panel 135 located and extending from at the end of the insert 110 distal to the pivot point 120 . The header panel 135 is separable from the remainder of the insert 110 along a line of perforations indicated by broken line 130 . FIG. 2 is a front elevation showing the holder 100 in an open disposition and with the header panel 135 removed. After purchase of the holder 100 , which in the present embodiment includes a gift card 105 removably mounted to the insert 110 , the header panel 135 is cut or torn off thereby reducing the size (length) of the insert 110 sufficiently to allow the insert 110 to pass into the confines of the sleeve 115 .
As shown in several of the figures, the insert 110 may include a generally centrally located aperture 140 that allows indicia on the back surface of the gift card 105 , such as a magnetic strip or barcodes, to be scanned or otherwise viewed or accessed.
FIG. 3 is a front elevation showing the holder insert 110 pivoted about pivot point 120 to a partially closed position. FIG. 4 is a front elevation showing the holder insert 110 pivoted fully to lie within the sleeve 115 in a fully closed position. FIG. 5 is a front elevation of the insert 110 prior to assembly of the holder 100 .
FIG. 6 is a plan view of material diecut to form the sleeve 115 . As shown, the sleeve 115 may comprise two main panels 115 a and 115 b , which form the sides of the sleeve 115 when assembled and contain the insert 110 within the sleeve 115 when the holder 100 is closed. The sleeve 115 may also comprise a subpanel 115 c that is used to join the main panels 115 a and 115 b to each other along side edge 115 d , thereby closing the sleeve 115 at side edge 115 d . Note that the sleeve 115 is also closed along bottom edge 115 e by the fold between the adjoining main panels 115 a and 115 b.
To assemble the sleeve 115 , adhesive is applied to subpanel 115 c , which is then folded inward so that the adhesive contacts the inner surface of main panel 115 b , thereby securing the main panels to each other along, and enclosing, sides 115 d and 115 e . Side 115 f remains open to receive the insert 110 . The main panels 115 a and 115 b , enclosed sides 115 d and 115 e and open side 115 f thereby cooperate to form a pocket structure of the sleeve 115 size to receive and hold the insert 110 . Side 115 f may include a finger notch 150 therein to provide a ready means of grasping the portion of the insert 110 within the notch 150 to withdraw the insert 110 from the sleeve 115 as may occur prior to removal of the gift card 105 from the insert 110 by a gift recipient.
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An assembly for holding a transaction card, such as a gift card, upon a panel that pivots to be received within a pouch, pocket or sleeve to hold and retain the card during transport and storage.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to snap-type swivel hooks for securement to cables and the like for passing over rollers, drums and the like and, more particularly, is concerned with a snap swivel hook assembly incorporating a ball swivel and recessed hook release mechanism.
2. Description of the Prior Art
Heretofore, swivel hooks attached to cables used in certain military applications, such as onboard U.S. Navy mine sweeping helicopters, have simply been commerically available types commonly used on modern pleasure sailing vessels. Such military applications contemplate that the cables and the swivel hooks attached thereto will be passed over and wound about rollers, drums, spools, sheaves and the like. These swivel hooks typically are attached to the cables by forming an eye in the cable, inserting it through the eye of the swivel part of the swivel hook and then passing the cable through the cable eye.
These swivel hooks as used heretofore in military applications have several drawbacks. First, they often break at the point where the swivel part of the swivel hook rotatably connects to the hook part of the swivel hook because the swivel and hook parts cannot withstand the cyclical bending which occurs when the swivel hook is forced over the rollers, drums, spools, sheaves and the like. Second, they typically have pins, rings or loops used to open and/or secure a latch part of the hook that will bend and thus become non-operational when high loads are imposed on the swivel hooks as they pass over rollers, drums, sheaves, spools and the like, or when high tension cables are wound over the swivel hooks as they are wound on a drum or spool.
Consequently, a need still exists for an improved design for a swivel hook which will overcome the drawbacks of the prior art without introducing new ones in their place.
SUMMARY OF THE INVENTION
The present invention provides a snap swivel hook assembly designed to satisfy the aforementioned need. The snap swivel hook assembly of the present invention incorporates a ball swivel and recessed hook release mechanism which are particularly designed to be able to pass over rollers, drums, sheaves, spools and the like without damaging the snap swivel hook assembly, catching or snagging on other equipment, or sacrificing the capability of the snap swivel hook assembly to maintain a load safely secured to the cable.
Accordingly, the present invention is directed to a snap swivel hook assembly which comprises: (a) a hook subassembly including (i) an arcuate-shaped hook body defining a cavity and having a pair of inner and outer end portions spaced apart from one another and defining an opening through the hook body to the cavity, (ii) an elongated connector stem attached to and extending from the inner end portion of the hook body, and (iii) an elongated latch member having a pair of first and second opposite end portions and being mounted at the first end portion to the outer end portion of the hook body so as to undergo pivotal movement between a closed position in which the latch member blocks the opening to the cavity in the hook body and the second end of the latch member is disposed adjacent to the inner end portion of the hook body and an opened position in which the latch member unblocks the opening to the cavity in the hook body and the second end portion of the latch member is spaced from the inner end portion of the hook body; and (b) a hook latch release mechanism adapted to secure the latch member at the second end portion thereof to the hook body at the closed position so as to prevent pivotal movement thereof to the opened position and for releasing the latch member at the second end portion thereof from the hook body so as to permit pivotal movement thereof to the opened position. The hook latch release mechanism is contained within an exterior profile of the hook subassembly defined by respective exteriors of the latch member and hook body thereof with the latch member at the closed position such that no portion of the hook latch release mechanism protrudes beyond such exterior profile of the hook subassembly to where the hook latch release mechanism can be snagged by an external device passing closely adjacent to the snap hook swivel assembly.
Additionally, the present invention is directed to a snap swivel hook assembly which comprises: (a) a hook subassembly including (i) an arcuate-shaped hook body defining a cavity and having a pair of opposite end portions spaced apart from one another and defining an opening through the hook body to the cavity, (ii) an elongated connector stem attached to and extending from one of the end portions of the hook body, and (iii) latch means mounted to the hook body to undergo pivotal movement between a closed position in which the opening to the cavity in the hook body is blocked and an opened position in which the opening to the cavity in the hook body is unblocked; and (b) a swivel subassembly coupled with the elongated connector stem of the hook body for concurrently undergoing rotational movement about and pivotal movement relative to the connector stem and thereby relative to the hook subassembly.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there is shown and described an illustrative embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following detailed description, reference will be made to the attached drawings in which:
FIG. 1 is a side elevational view, with portions broken away and sectioned, of a snap swivel hook assembly of the present invention.
FIG. 2 is a front elevational view of the assembly as seen along line 2--2 of FIG. 1.
FIG. 3 is a rear elevational view of the assembly as seen along line 3--3 of FIG. 1.
FIG. 4 is a side elevational view, with portions broken away and sectioned, of an arcuate-shaped hook body of the assembly of FIG. 1 being shown by itself.
FIG. 5 is front elevational view of the hook body as seen along line 5--5 of FIG. 4.
FIG. 6 is a rear elevational view of the hook body as seen along line 6--6 of FIG. 4.
FIG. 7 is a side elevational view, with portions broken away and sectioned, of a latch member of the assembly of FIG. 1 being shown by itself.
FIG. 8 is a rear elevational view of the latch member as seen along line 8--8 of FIG. 7.
FIG. 9 is a side elevational view of a release pin of the assembly of FIG. 1 being shown by itself.
FIG. 10 is a front elevational view of a release tab of the assembly of FIG. 1 being shown by itself.
FIG. 11 is a cross-sectional view of the release tab taken along line 11--11 of FIG. 10.
FIG. 12 is a top plan view of the release tab as seen along line 12--12 of FIG. 10.
FIG. 13 is a side elevational view of a swivel connector of the assembly of FIG. 1 being shown by itself.
FIG. 14 is a bottom plan view of the swivel connector as seen along line 14--14 of FIG. 13.
FIG. 15 is a longitudinal sectional view of the swivel connector taken along line 15--15 of FIG. 14.
FIG. 16 is a longitudinal sectional view of a swivel ball of the assembly of FIG. 1 being shown by itself.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings and particularly to FIGS. 1 to 3, there is illustrated a snap swivel hook assembly, generally designated 10, of the present invention. Basically, the snap swivel hook assembly 10 includes a hook subassembly 12 and a swivel subassembly 14 coupled thereto to undergo concurrently both 360°. rotational movement relative to the hook subassembly 12 and a limited amount, such as 15°. in opposite directions from a longitudinal axis L through the hook subassembly 12, of side-to-side rocking or pivotal movement relative to the hook subassembly 12.
Referring to FIGS. 1-12, the hook subassembly 12 of the snap swivel hook assembly 10 includes a hook body 16 having an arcuate shape defining a cavity 18 of fixed size for receiving components, such as a portion of a cable and the like, to secure the cable to the hook body 16. The hook body 16 has a pair of inner and outer end portions 16A, 16B spaced apart from one another and defining an opening 20 through the hook body 16 to the cavity 18. The hook subassembly 12 also includes an elongated connector stem 22 fixedly attached to and extending outwardly from the inner end portion 16A of the hook body 16 along the longitudinal axis L of the hook subassembly 12.
The hook subassembly 12 of the snap swivel hook assembly 10 further includes an elongated latch member 24 mounted to the hook body 16 to undergo pivotal movement between a closed position, as shown in solid line form in FIG. 1, in which the opening 20 to the cavity 18 in the hook body 16 is blocked and an opened position, as shown in dashed line form in FIG. 1, in which the opening 20 to the cavity 18 in the hook body 16 is unblocked. The latch member 24 has a generally straight shape and a pair of first and second opposite end portions 24A, 24B. The outer end portion 16B of the hook body 16 is bifurcated so as to define a pair of ears 26 each with a central aperture 28. The latch member 24 which has an aperture 30 through its first end portion 24A is disposed at its first end portion 24A between the pair of ears 26 on the outer end portion 16B of the hook body 16 with the aperture 30 of the latch member 24 aligned with the central apertures 28 in the hook body 16. A suitable fastener 32, such as a rivet, is installed through the aligned apertures 28, 30 so as to pivotally mount the latch member 24 to the hook body 16.
The latch member 24, being so mounted, is thereby adapted to undergo pivotal movement between the closed position in which the latch member 24 blocks the opening 20 to the cavity 18 and the opened position in which the latch member 24 unblocks the opening 20 to the cavity 18. In the closed position, the latch member 24 is disposed along a generally linear path across the opening 20 between the inner and outer end portions 16A, 16B of the hook body 16 with the second end portion 24B disposed adjacent to and preferably in contact with the inner end portion 16A of the hook body 16. On the other hand, in the opened position, the latch member 24 is pivoted along an arcuate path of movement, as represented by arrow A, away from the opening 20 between the inner and outer end portions 16A, 16B of the hook body 16 with the second end portion 24B disposed away and spaced from the one side of the inner end portion 16A of the hook body 16. As is clearly shown in FIG. 1, the cavity 18 is defined solely within the hook body 16 and remains fixed in size regardless of whether the latch member 24 is disposed in the opened or closed position relative to the hook body 16.
The hook subassembly 12 of the snap swivel hook assembly 10 further includes a hook latch release mechanism 34 for securing the latch member 24 to the hook body 16 at the closed position so as to prevent pivotal movement thereof to the opened position and for releasing the latch member 24 from the closed position so as to permit pivotal movement thereof to the opened position. More particularly, the hook latch release mechanism 34 includes a passageway 36 formed in and extending through the inner end portion 16A of the hook body 16. The passageway 36 extends between first and second ends 36A, 36B thereof. The first end 36A of the passageway 36 opens at a first side 16C of the hook body 16 adjacent to the latch member 24, whereas the second end 36B of the passageway 36 opens at a second side 16D of the hook body 16 remote from the latch member 24.
The hook latch release mechanism 34 also includes a recessed notch 38 formed in the inner end portion 16A of the hook body 16 adjacent to the second side 16D thereof and extending transversely to and intersecting with the second end 36B of the passageway 36 through the hook body 16. The recessed notch 38 has a pair of opposite open sides 38A opening at respective opposite lateral sides 16E of the hook body 16 adjacent to the second side 16D thereof and an open end 38B opening at the second side 16D of the hook body 16 and extending between the lateral sides 16E of the hook body 16 and merging into the pair of opposite open sides 38A of the recessed notch 38.
The hook latch release mechanism 34 also includes a hole 40 defined in the second end portion 24B of the latch member 24. The hole 40 is aligned with the first open end 36A of the passageway 36 through the inner end portion 16A of the hook body 16 when the latch member 24 is at the closed position relative to the hook body 16.
Additionally, the hook latch release mechanism 34 includes a release pin 42, a coiled spring 44, and a release tab 46. The release pin 42 has a forward plunger 48 and a rearward shaft 50 axially aligned with and rigidly connected to the forward plunger 48. The forward plunger 48 has a latching end 48A and the rearward shaft 50 has an opposite actuating end 50A. The forward plunger 48 is larger in diameter than the rearward shaft 50 and, correspondingly, the hole 40 of the latch member 24 and a forward portion 36C of the passageway 36 which receive the forward plunger 48 of the release pin 42 are larger in diameter than a rearward portion 36D of the passageway 36 which receives the rearward shaft 50 of the release pin 42. The release pin 42 so sized thus is slidably mounted in the passageway 36 for undergoing reciprocal movement through and relative to the hook body 16 between an extended position, as seen in solid line form in FIG. 1, and a retracted position, as seen in dashed line form in FIG. 1. The passageway 36 and hole 40 also are oriented relative to the arcuate path of movement of the latch member 24, as represented by arrow A, such that the latching end 48A of the forward plunger 48 of the release pin 42 when extended into the hole 40 in the latch member 24 engages a continuous interior sidewall 40 therein forming the hole 40 so as to obstruct and prevent movement of the latch member 24 away from the latching end 48A of the release pin 42 when in the extended position.
The coil spring 44 of the mechanism 34 is disposed in the larger diameter forward portion 36C of the passageway 36 and positioned over the rearward shaft 50 of the release pin 42 and thus captured between a rear end 48B of the forward plunger 48 of the release pin 42 and a forwardly facing annular interior shoulder 52 in the hook body 16 which provides a transitional step between the larger diameter forward portion 36C and smaller diameter rearward portion 36D of the passageway 36. The coil spring 44 is under sufficient compression to bias the release pin 42 to move from right to left in FIG. 1 and thus move and maintain the latching end 48A of the plunger 48 to and at the extended position shown in solid line form in FIG. 1.
The release tab 46 of the mechanism 34 is disposed substantially within the recessed notch 38 of the hook body 16 and attached to the opposite actuating end 50A of the rearward shaft 50 of the release pin 42. The release tab 46 has opposite ends 46A disposed adjacent to and exposed at the pair of opposite open sides 38A of the recessed notch 38. Although the release tab 46 is substantially received and thus "hidden" within the recessed notch 38 of the hook body 16, the opposite open sides 38A of the recessed notch 38 provides access to the opposite ends 46A of the release tab 46 by a user for gripping the release tab 46 between two fingers of the user in order to pull on and slidably move the release pin 42, against the biasing force of the coiled spring 44, from the extended position, as shown in solid line form in FIG. 1, to the retracted position, as shown in dashed line form in FIG. 1.
To recapitulate, in the extended position of the release pin 42, the latching end 48A of its forward plunger 48 projects from the first end 36A of the passageway 36 of the hook body 16 into the hole 40 of the latch member 24 so as to prevent pivotal movement of the latch member 24 away from the closed position to the opened position. On the other hand, in the retracted position of the release pin 42, the latching end 48A of its forward plunger 48 is withdrawn from the hole 40 through the second end portion 24B of the latch member 24 to within the first open end 36A of the forward portion 36C of the passageway 36 in the hook body 16 so as to be clear of engagement with the interior sidewall 40A in the latch member 24 and thereby permit pivotal movement of the latch member 24 away from the closed position to the opened position.
From the foregoing description of the hook latch release mechanism 34, it can be readily observed and understood that the mechanism 34 is contained and "hidden" within an exterior profile of, or an envelope occupied by, the hook subassembly 12 being defined by the respective exteriors of its latch member 24 and hook body 16 when the latch member 24 is at the closed position. No portions of the hook latch release mechanism 34 protrude beyond such exterior profile or envelope of the hook subassembly 12 to where portions of the mechanism 34 can be snagged and thus actuated or damaged by foreign equipment located or passing closely adjacent to the snap hook swivel assembly 10.
Referring to FIGS. 1-3 and 13-16, the swivel subassembly 14 of the snap swivel hook assembly 10 is coupled with the elongated connector stem 22 extending from the hook body 16 of the hook subassembly 12 of the assembly 10 for undergoing concurrently rotational movement about and pivotal movement relative to the central longitudinal axis L of the connector stem 22 and thereby relative to the hook subassembly 12. More particularly, the swivel subassembly 14 includes a swivel ball 54 and a swivel connector 56. The swivel ball 54 has an exterior annular surface 54A of a convex shape and, more specifically, of a substantially semispherical shape. The swivel connector 56 has a connector body 58 in the shape of an annular ring with inner and outer opposite end portions 58A, 58B, and a swivel collar 60 fixedly attached on and extending laterally outwardly from the inner end portion 58A of the connector body 58.
More particularly, the swivel collar 60 of the swivel connector 56 defines an outer annular seat 62 in the form of an interior annular surface of a concave shape conforming to the convex shape of the exterior annular surface 54A of the swivel ball 54 so as to mount the swivel ball 54 on the outer annular seat 62 of the swivel collar 60 to undergo swiveling movement relative thereto. The swivel collar 60 also defines an inner central bore 64 through the connector body 58 having an outer open end 64A surrounded by the outer annular seat 62, an inner open end 64B spaced from the outer open end 64A, and a continuous annular sidewall 64C extending between the outer and inner open ends 64A, 64B. The outer and inner open ends 64A, 64B are both larger in diameter than the elongated connector stem 22 of the hook subassembly 12 so as to adapt the swivel collar 60 to receive the connector stem 22 through the inner central bore 64 and permit the rotational movement of the swivel subassembly 14 about the longitudinal axis L of the hook subassembly 12 defined by the connector stem 22. Furthermore, the inner open end 64B of the inner central bore 64 of the swivel collar 60 is larger in diameter than the outer open end 64A thereof so as to provide the continuous annular sidewall 64C of the inner central bore 64 with a conical shape and thereby permit the pivotal movement of the swivel subassembly 14 relative to the hook subassembly 12. In one example, the conical or flared configuration of the sidewall 64C is selected to permit about 15°. of side-to-side arcuate pivotal movement of the swivel subassembly 14 in opposite directions away from the longitudinal axis L of the hook subassembly 12.
The swivel subassembly 14 further includes suitable means for detachably attaching the outer end 22A of the elongated connector stem 22 of the hook subassembly 12 to the swivel ball 54 of the swivel subassembly 14. One suitable form of such detachable attaching means is complementary external and internal sets of threads 66, 68 defined respectively on the outer end 22A of the connector stem 22 and within a central opening 70 defined through the swivel ball 54. This form of the attaching means provides for a convenient and easy manner by which the hook subassembly 12 and swivel subassembly 14 are assembled to and disassembled from one another.
From the foregoing description of the swivel subassembly 14, it can be readily understood that the hook and swivel subassemblies 12, 14 no longer provide the snap swivel hook assembly 10 as a longitudinally rigid device. Instead, the snap swivel hook assembly 10 is articulated longitudinally so as to permit pivoting of the swivel subassembly 14 relative to the hook subassembly 12 through a limited amount, such as 15°, to either side of the longitudinal axis L thereof which thereby reduces vulnerability of the assembly 10 to bending stresses and ultimately fracture at the swivel point of the assembly 10 as it passes over and about the curved surfaces of rollers, drums, spools, sheaves and the like.
It is thought that the present invention and its advantages will be understood from the foregoing description and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely preferred or exemplary embodiment thereof.
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A snap swivel hook assembly includes a hook subassembly having a hook bodynd an elongated stem portion extending therefrom, and a swivel subassembly having a swivel collar and swivel ball seated thereon and being coupled with the elongated connector stem of the hook subassembly such that swivel subassembly can undergo concurrently rotational movement about and a limited degree of pivotal movement relative to hook subassembly. The hook subassembly also includes a hook latch release mechanism adapted to secure a latch member of the hook subassembly at a closed position relative to a cavity defined in the hook body so as to prevent pivotal movement of the latch member from the closed position to an opened position. The hook latch release mechanism also is actuatable to release the latch member from the closed position so as to permit pivotal movement thereof to the opened position. A release tab of the hook latch release mechanism is positioned within a recessed notch in the hook body to prevent it from snagging or catching on an external object while, at the same time, making it accessible for manual gripping between fingers of a user to actuate the hook latch release mechanism.
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FIELD OF THE INVENTION
The invention pertains to supervision circuits of a type usable in ambient condition detection systems. More particularly, the invention pertains to such circuits for supervising message generation devices and audio output links.
BACKGROUND OF THE INVENTION
Ambient condition detection systems for supervising one or more conditions in a selected region are known. One such system is disclosed and claimed in U.S. Pat. No. 5,539,389, entitled "Enhanced Group Addressing System", assigned to the assignee hereof. The disclosure of the '389 patent is incorporated herein by reference.
Ambient condition systems of the type disclosed in the '389 patent can be configured to detect, in one embodiment, fire profiles based on detected ambient conditions such as smoke, temperature or gas. In such fire detecting systems, it is known to provide audible and visible outputs, horns and strobe lights. These devices can be used to provide human perceptible indications of the presence of a detected fire profile. In this regard, voice annunciation systems have also been used. In such systems, audible messages can be prestored and played back at appropriate times to provide yet another form of communication for individuals in the region being supervised.
Where such annunciation systems are provided, it is desirable to be able to test same without alarming any individuals in the region where the test is being conducted. Preferably such testing could include not only annunciation system circuitry but also associated audio output cables. Also, it would be preferable if such supervision circuitry could be implemented without adding significantly to the cost or complexity of the associated system.
SUMMARY OF THE INVENTION
Message generator supervisory circuitry includes supervisory storage circuitry of a sampled message stored in the message generator. Control circuitry coupled to the message generator and to the storage circuitry causes the generator to output, as an audio signal, the stored message.
The output audio is in turn sampled by the control circuitry. The sampled audio is compared to the sampled, previously stored message. If the two signals are substantially the same, the message generator will have output the expected message or audio. If the signals differ, a tone generator will continue generating audio.
In one aspect, an analog output message can be cycled and sampled a number of times so as to form an average output sampled output signal. This averaged sampled signal can then be compared with a previously sampled and stored representation.
In yet another aspect, an averaged representation of the message can be pre-stored for subsequent comparison to the test analog output signal. In yet another aspect, when the test analog signal is being produced by the message generator, the audible output therefrom can be suppressed so as not to alarm individuals in the immediate area of the respective output transducers.
In a further aspect, various other types of audible and non-audible communications can be output by a system. These include paging messages, tones, background music and/or live announcements of all types.
In another embodiment, the audio output cables can be supervised even in the presence of output messages, paging announcements, background music, and tone generation. A supervisory signal can be applied to the output cables. The supervisory signal is electrically distinguishable from the electrical representation of any output signals that can be produced by the message generator or by any other input source. Further, the output transducers either do not respond to the supervisory signal or the output transducers are isolated from such signals.
The communications normally expected to be output by the system fall into a predetermined band which need not be limited to audio. The supervisory signals are all out-of-band signals. It will be understood that the exact details of the differences between the normally expected communications and supervisory signals are not limitations of the invention.
In one aspect, the supervisory signals can be in the form of a DC bias applied to the audio output lines. The output transducers, such as speakers, can be isolated by either capacitive or inductive coupling.
In another aspect, high frequency supervisory signals can be coupled to the audio output cables. The high frequency signals can be detected to verify cable integrity. However, the output transducers can be decoupled therefrom to minimize distortion. Alternately, low pass characteristics of the output transducers can be used to filter out the supervisory signals.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiment thereof, from the claims and from the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a supervised message generator;
FIG. 2 is a flow diagram illustrating steps of a method of supervising the generator of FIG. 1;
FIG. 3 is a block diagram illustrating exemplary audio output cable supervisory circuitry; and
FIG. 4 is a block diagram of an ambient condition detection system which incorporates supervisable message generation circuitry.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will be described herein in detail specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.
FIG. 1 illustrates, in block diagram form, a supervisable message generation system 10. The system 10 incorporates message generation circuitry 12. The circuitry 12 could be implemented using commercially available digital signal processing circuitry such as Information Storage Devices type ISD2560. It will be understood that the exact details of the message generator 12 are not a limitation of the present invention.
The message generator 12 includes an audio input port 12a and an audio output port 12b. Control and data buses 12c couple the generator 12 to a programmable control unit 16.
The control unit 16 includes read/write memory for data as well as read-only memory usable for storage of control programs if desired. In addition, the unit 16 could also include magnetic storage in the form of disk drives and the like.
The control unit 16 in addition to interfacing with the generator 12 receives analog inputs at converter 18. The converter 18 samples the analog inputs, converts same to a binary representation which can then be stored in the storage units of the control unit 16.
A source of analog signals, such as microphone 20 can be used for entering one or more messages to be subsequently output by the generator 12. The analog signal for the microphone, on a line 20a is coupled to the audio input port 12a of the generator 12.
A tone generator 21, which could operate under the control of processor 16, is coupled to line 12d. The generator 21 can be used to produce one or more message-type tones.
Paging messages can be input via microphone 20. Alternately, other types of line messages or background music can be input by microphone or auxiliary jacks.
In a record mode, an electrical signal on the line 20a representative of a message to be output, is sampled and stored in both the generator 12 and storage circuitry for the control unit 16. It will be understood that the generator 12 could sample and store a plurality of messages without limitation. It will also be understood that various sources of audio signals can be used instead of microphone 20 without departing from the spirit and scope of the present invention.
Subsequent to sampling and storing one or more messages in generator 12 and control unit 16, the control unit 16, in accordance with a prestored control program, can command the generator 12 to output a selected message at the port 12b. The output message, in analog form, on line 12d is coupled to an input of the converter 18. The analog message is also coupled to an input of amplifier 24.
Amplifier 24 is in turn coupled to an output path or cable 24a. It will be understood that the amplifier 24 operates under control of the control unit 16 such that the output from the amplifier 24 can be disabled in response to a command or signal from the control unit 16.
For supervisory purposes, the analog signal on the line 12d can be sampled at converter 18 and compared by control unit 16 to a representation thereof prestored at the control unit 16 at the same time that the message had been previously stored in the generator 12. Thus, the supervisory mode of the system 10 not only verifies proper operation of the generator 12 to sample and store the selected message but it also verifies that the generator 12 has properly retrieved the stored representation thereof and converted that representation back into an analog signal for output to the amplifier 24. During the supervisory process, the output from the amplifier 24 can be disabled so as not to alarm individuals in the vicinity of one or more of the output transducers such as loud speakers 30.
Coupled between the amplifier 24 and the speakers 30 is audio cable supervisory circuitry 40. While the system 10, as illustrated in FIG. 1, can be used with circuitry 40, it will be understood that the circuitry 40 is not a requirement. The system 10 can be directly coupled to the speakers 30 by cable 24a.
FIG. 2 illustrates the steps of a process of supervising the functioning of generator 12. In a first phase 100, one or more messages is recorded in both generator circuitry 12 and control element circuitry 16.
In a step 102 a message is input. That message is stored in the generator 12. The stored message is read out from the generator 12 as an audio, analog output, in a step 103. The message is then sampled by converter 18 in a step 104. The sampled representation is stored in control element 16 in step 106.
For filtering and smoothing purposes, the converter 18 can make multiple samples, for example four samples, at each sample point of the message being stored. In this instance, an average value can then be stored by the control unit 16. The averaged value, a binary image of the message can be stored for example in nonvolatile memory.
Subsequently, in a verification phase 110, the generator 12 on line 12d produces an analog representation of a selected prestored message in a step 112. That analog representation is converted in a step 114 via converter 18.
The result of the conversion step 114 is then compared with a respective prestored image of the message by control unit 16 in a step 116. If the two representations are substantially the same, the generator 12 can be expected to be operating in a normal condition and another message can be generated for supervisory purposes.
In the event that the messages are different, in a step 118, a determination is made as to whether an alarm state is present. If the system is not in alarm, a trouble or error indicator can be generated for operator follow-up or action in a step 120. Alternately, if this event occurs while the system is in an alarm state, the tone generator 21 can be used to provide an audible signal to the transducers 30 in a step 122. The tones will be output instead of the pre-stored messages.
FIG. 3 illustrates details of exemplary audio cable supervisory circuitry 40. Cable supervision is carried out using out of band supervisory signals.
An output band of communications signals such as audio is used for audible voice messages, tones, background music and the like. This band could also include ultrasonic or non-audible frequencies. Supervisory, out of band, signals that can be separated from the communications signals are used for cable supervision.
As illustrated in FIG. 3, a differential output from the amplifier 24, on conductors W1 and W2 is coupled to the plurality of speakers 30. The supervisory circuitry 40 includes a first resistor R1 coupled across the conductors W1 and W2 in parallel with an end of line element 32. The element 32 could be a resistor of a selected value.
A second resistor R2 is coupled between one end of resistor R1 and a source of DC voltage. A third resistor R3 is coupled between a second end of the resistor R1 and ground.
The exact value of the DC voltage source is not a limitation of the present invention. Forty volts can be used for example.
An instrumentation amplifier 42 is coupled across the audio output conductors W1 and W2 and produces a single-ended output on the line 40a. In an exemplary embodiment, resistors R2 and R3 are chosen to have substantially equal resistance values. Resistor R1 is chosen to have a resistance value substantially equal to that of the end of line element 32.
These resistor value ratios can be chosen so that under normal conditions the difference between the voltage from conductor W1 to ground and voltage from conductor W2 to ground will be half way between the maximum voltage difference and the minimum voltage difference. Since R3=R2, if conductors W1 and W2 become shorted together, the voltage from W1 to ground (V1) and voltage from W2 to ground (V2) will be equal, therefor the difference=zero Vdc (minimum voltage). If the end of line element 32 is no longer in parallel with R1 for whatever reason (open wire, not connected etc.), the maximum differential voltage between W1 and W2 will be present.
The end result is three distinct differential voltage level ranges that correspond to three wiring conditions. The NORMAL (end of line element 32 in place, no wire faults) condition results in a nominal voltage level of 2 Vdc. The OPEN (no end of line element 32 or an open wire fault) condition is represented by a voltage level of 4 Vdc. The SHORT (end of line element 32 shorted, W1 and W2 shorted together) condition is represented by a voltage level of 0 Vdc.
The differential voltage is fed through the instrumentation amplifier 42 whose output is input to the analog-to-digital converter. Software or control programs for the unit 16 periodically performs an analog to digital conversion on the instrumentation amplifier output voltage (Vsup). Where the amplifier gain equals 1, the supervisory voltage levels defined previously will remain the same. A nominal range of 1.5-2.5 Vdc for NORMAL, >3 for OPEN, and <1 Vdc for SHORT can be used. Based on these three voltage ranges, the control unit 16 determines whether a trouble condition (Short or Open Wire Fault) exists and in response thereto generates a visual or audible indication or message.
In order to provide supervision while audio voltage is present on the output lines W1, W2, the AC audio voltage is filtered out. This can be accomplished via low pass filters on each input of the instrumentation amplifier 42 as well as positive and negative feedback filters in the amplifier's output stage. Since the supervisory voltage is DC, the audio output is not affected.
FIG. 4 illustrates in block diagram form an ambient condition detection system 60 which incorporates annunciator supervisory circuitry, such as the circuitry 10. Elements of the system 60 which have been previously discussed have been identified with previously assigned identification numerals.
The exemplary system 60 is a form of an ambient condition supervisory system such as might be used to monitor a region for intrusion, fire, gas or the like. System 60 includes a control unit 62.
The control unit 62 incorporates a programmable processor unit 161, comparable to the control unit 16. The unit 16-1 is coupled by interface circuitry 16-2 to a communication link 64. The communication link can, for example, enable the unit 16-1 to carry on bidirectional communications with a plurality of modules 66.
The plurality 66 can include as a subgroup a plurality of ambient condition detectors. Representative detectors include motion sensors, entry/access indicators, fire detectors such as smoke, flame or thermal detectors as well as gas detectors.
The interface circuit 16-2 are also coupled to a communication link 68. The link 68 enables processing unit 16-1 to communicate with a plurality of output devices 70. The devices 70 could include audible and visual indicators such as horns or strobe units.
The interface circuitry 16-2 is also coupled to message generation circuitry 12. Analog input signals, which could be from a microphone or another prestored source of messages are coupled by the line 20a to both the message generator 12 and analog/digital converter 18-1 which operates under the control of processing unit 16-1. Other elements of the message generation system of the system 60 correspond to the elements previously discussed with respect to FIGS. 1-3. No further discussion thereof is necessary.
In operation, system 60 is driven by a plurality of control programs, some of which are resident at the unit 62. Others are resident at various members of the pluralities 66, 70 and at the message generator 12.
In response to a detected predetermined condition, such as a fire profile, the system 60, as will be understood by those skilled in the art, will actuate the alarm indicating members of the plurality 70. Additionally, the unit 62 can, via a message generator 12, generate audible messages for individuals throughout the region being supervised via the plurality of output transducers, loudspeakers 30.
As discussed, previously the processor 16-1 is able to supervise the operation of the message generation system 12. The processor 16-1 is also able to supervise conditions on the output audio lines W1 W2.
It will be understood that the system 60 could use and supervise the message generator 12 to the exclusion of the output line supervisory circuit 40 if desired.
The output audio lines can be supervised when no communication is present thereon (standby) and during times when a communication is being sent to the transducers 30. Tones can be automatically generated, by the generator 21, if the message generator 12 does not properly respond to the supervision process. This thus provides a back-up form of communication for individuals in the region being supervised. Both the message generator 12 and the tone generator 21 can be supervised when the system is in a quiescent, stand-by state or while in an active state.
From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the novel concept of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.
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Circuits for supervising message generators and audio output cables include memory for binary storage of messages previously recorded in a message generator. As the generator is cycled to produce an audio output, that analog output is sampled and compared to the previously stored binary representation. A match indicates a successful generation of the message. The cables can be supervised by applying a DC bias thereto and detecting the voltage present on the respective cable. Line integrity is indicated where the cable DC voltage falls in an expected range.
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RELATED APPLICATIONS
[0001] This application claims priority benefit of U.S. 60/587,306, filed on Jul. 12, 2004, and incorporated herein by reference.
TECHNICAL FIELD
[0002] The invention relates generally to synthesis of long sequences of DNA.
INTRODUCTION
[0003] Recently there has been considerable interest in the synthesis of sequences of DNA of gene length (˜1-2 kilobases) up to the size of small bacterial genomes (˜several megabases) concatenated from a series of synthetic oligonucleotides. Unfortunately the error rate of the best chemical syntheses for such synthetic oligonucleotides (acid labile or photo labile protection group chemistries) are typically on order of 1 error per 100 nucleotides making the resulting long constructs highly error laden.
[0004] One approach which has been employed by Venter et al. (Proceedings of the National Academy of Sciences, vol. 100, p. 15440-15445, Dec. 23, 2003, incorporated herein by reference) is to use best practices in synthesizing precursor oligonucleotides typically by co-synthesizing the complimentary oligonucelotides and running a thermally denaturing gel. Such practices can yield starting oligonucleotides with error rates of about 1 per 1000. As a next step small functional constructs such as viral genomes (˜5 Kb) can be constructed and tested for viability. In such a case a typical 5 Kb construct is likely to have 5 errors. However if on average there is a single error per 1000 bases then in any 500 base region there is a probability of ˜½ of having an error in that region. Thus for a 5 Kb construct consisting of ten 500-base regions there is a probability of (½) 10 = 1/1024 of creating the correct 5 Kb sequence. If one has a functional screen, such as the viability of the construct (e.g. viral infectivity) then one can pick out the correct construct from a colony. Alternatively one can randomly sequence members of the colony to be sequenced. (Note that one would have to sequence approximately 1024 members from a colony to find a 5 Kb sequence which was error free.) Unfortunately, although this approach is successful for shorter sequences, as the sequence length gets larger there is a high likelihood that no fully correct sequence exists in the pool of synthesized sequences. In order to synthesize such large sequences it is desirable to correct those errors which are found as opposed to merely sort them. One means of correcting sequence errors is to synthesize new oligonucleotides to replace regions which contain an error by means of site directed mutagenesis.
[0005] In co-pending application number U.S. Ser. No. 10/990,939 filed 11-17-2004 and claiming priority benefit of application number U.S. 60/520,751 filed 11-17-2003 both entitled “Nucleotide Sequencing via Repetitive Single Molecule Hybridization” and both incorporated herein by reference, we described the utility of using site directed mutagenesis to correct errors in a synthetic DNA construct found by sequencing. Subsequently, Venter et al. (Proceedings of the National Academy of Sciences, vol. 100, p. 15440-15445, Dec. 23, 2003, incorporated herein by reference) described the utility of using site directed mutagenesis to repair small numbers of remaining errors as a final clean up step in fabrication. Although useful, both of these approaches suffer from the fact that the repair oligos themselves have the same native error rate as the build oligos did initially.
[0006] Here we disclose a means for fabricating long DNA constructs assembled from imperfect oligos by means of repetitive cycling of the steps consisting of: [1] yes/no sequence verification in each subregion of the long DNA construct; [2] fabrication of repair oligos predicated on the outcome of such sequence verification; and, [3] replacement of error-containing subregions of the DNA construct with such repair oligos. A preferred means for yes/no sequence verification is by means of a hybridization array. A preferred means of replacement of error-containing regions with repair oligos is by site directed mutagenesis.
SUMMARY
[0007] An aspect of the invention is a method for correcting errors in the synthesis of long sequences of DNA. In this approach an initial long DNA sequence is synthesized by means of creating an array of overlapping build oligonucleotides (e.g. 70 mers) using conventional array synthesis techniques. Next these oligos are released from the surface and allowed to hybridize to form a longer ‘walked up’ sequence. Using PCR assembly or ligase assembly the ‘walked up’ sequence can by covalently stitched together to form a longer sequence of double or single stranded DNA. Such a sequence will still possess (at best) the native synthetic error rate of the build oligo 1:100. This long DNA sequence is then incubated on a complimentary chip-based hybridization array to undergo yes/no sequence verification in each subregion (e.g. 35 nucleotide span) of the long DNA construct. Using this information a new repair oligo array is fabricated in which a repair oligo is synthesized for each subregion found to contain an error. Such repair oligos can then correct for such errors via the approach of site directed mutagenesis. If the appropriate sub region size is chosen (i.e. a size for which the probability of an error is less than one and preferably ˜½) repetition of this process yields a convergence toward an error free synthesized long DNA sequence.
[0008] Note that in certain cases one may wish to only synthesize a single molecule of any given oligo (and then amplify it if need be) so that there does not exist a population of errors within any one type of oligo.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The drawings are heuristic for clarity. The foregoing and other features, aspects and advantages of the invention will become better understood with regard to the following descriptions, appended claims and accompanying drawings in which:
[0010] FIG. 1 is a schematic drawing of an oligonucleotide chip with build oligos showing nucleotide level detail.
[0011] FIG. 2 is a schematic drawing of an oligonucleotide chip with build oligos.
[0012] FIG. 3A is a schematic drawing of build oligos which have been released from a chip and have hybridized (‘walked up’) to form a longer double stranded construct.
[0013] FIG. 3B is a schematic drawing of a double stranded long DNA construction from build oligos which have hybridized and then been ligated.
[0014] FIG. 4 is a schematic of a long single stranded DNA construct constructed from build oligos introduced onto a gene chip to analyze the presence or absence of particular base sequences in the single stranded DNA construct.
[0015] FIG. 5 is a schematic of an oligonucleotide chip with repair oligos.
[0016] FIG. 6 is a flowchart of steps for fabricating nearly perfect long DNA constructs from imperfect oligonucletides.
[0017] FIG. 7 is a table indicating the number of cycles, M*, of sequencing and repair required to build a nearly perfect long DNA construct.
DETAILED DESCRIPTION
[0018] Described below is a preferred method for carrying the construction of a long, relatively error-free DNA construct from error-containing oligos.
[0019] Referring to FIG. 1 a build oligonucleotide chip 10 with build oligo spots S 1 , S 2 etc. of length O B nucleotides (e.g. O B =68; typically O B will be set to twice the subregion size Q—see below) may be fabricated by standard means for fabricating DNA chips. Such oligos can be suitably designed that they can be released from the surface and further that they posses partially overlapping complimentary sequences such that when released they assemble into longer double stranded DNA sequences. We note that within any one build oligo spot (e.g. S 1 ), the sequence of individual oligos can have variations due to errors in synthesis within a single spot.
[0020] Referring to FIG. 2 as an example, a build oligonucleotide chip 10 is fabricated with build oligo spots S 1 , S 2 , S 3 , S 4 , S 5 , S 6 designed to hybridize into a longer DNA construct when released from the chip.
[0021] Oligos, S 1 -S 6 , may then be released from the chip and assembled into a longer double stranded DNA contruct ( 15 in FIG. 3A ). The construct may further be ligated with ligase to form covalent top ( 20 ) and bottom ( 30 ) long DNA strands ( FIG. 3B ) together comprising a long DNA construct 35 . It is important for future steps that if construct 35 need be amplified it is done by amplifying from a single initial copy (either by PCR or cloning) so that there do not exist distributions of errors within the long DNA construct.
[0022] At this point the DNA strands still possess the native error rate of the initial oligonucleotides. Consider the example where the native synthetic error rate for on-chip oligonucleotide synthesis, ε, is 0.98. In this case the probability of an error in any given subregion which is Q nucleotides in length is (1−ε) Q . For convenience we can choose the length, Q, of our subregions such that there is a probability of ½ of there being an error in any given sub-region. In our example Q= 34 bases. Typically O B is set to be 2Q.
[0023] We now wish to query our long DNA construct to see whether in each subregion of Q bases we have an error as compared to the initially intended sequence. This can readily be carried out by means of dehybridizing our long double stranded DNA construct ( FIG. 3B ) into a single stranded DNA construct strand (e.g. top strand 20 — FIG. 4 ) and then, referring to FIG. 4 exposing it to a hybridization chip array 40 containing complimentary oligos S′ 2A , S′ 2B , S′ 4A , S′ 4B and S′ 6A , S′ 6B in which S′ 2A is complimentary to the first half of S 2 and S′ 2B is complimentary to the second half of S 2 etc. Note that the length of the oligos on the hybridization array are typically Q in length and shorter than O B . If there is an error in the DNA construct strand, for example in the first half S 4 then there will be less prevalent binding of the DNA construct strand to the corresponding S′ 4A spot on the hybridization array chip. Such lack of binding can be read out by suitably fluorescently tagged DNA construct strands.
[0024] In order to repair errors that become known from binding to the hybridization array, such data may be used to direct the synthesis of repair oligos, typically of length Q (see FIG. 5 ). Such oligos may then be used to repair errors in the long DNA construct by means of site directed mutagenesis. It is important to note that for each repair oligo we do not wish to have sequence variation: thus we can either amplify up from a single repair oligo or clone it into an organism and amplify the oligo in-vivo.
[0025] An alternative approach to site directed mutagenesis is to shear or enzymatically cut the long DNA construct into smaller pieces and incubate them in a population of repair oligos (all repair oligos of each type being identical as noted above) and then to carry out reassembly by means of polymerase chain assembly in the presence of an abundance of repair oligo.
[0026] FIG. 6 shows a flowchart of the steps for fabricating nearly perfect long DNA constructs from imperfect oligonucletides as delineated above and further comprising repetition of the last 3 steps for M* cycles until convergenge to a nearly perfect construct is achieved.
[0027] The required number of cycles, M*, may be calculated as follows:
M*=−Log[N(1−ε)]/Log[1−P m /2] where N is the length of the desired long DNA construct, ε is the per-base error rate for oligonucleotide synthesis, and P m is the probability of the repair oligo properly replacing the native error-containing region via site directed mutagenesis.
[0029] FIG. 7 is a table indicating the number of cycles, M*, of sequencing and repair required to build a nearly perfect long DNA construct of length N. As can be seen from the table both P m and ε strongly affect the number of cycles M* which are required. Alternatives to site directed mutagenesis discussed above may have a strong beneficial effect on the effective P m . Similarly, pre-purification of the build oligos by thermal gel shift or other enzymatic means can greatly increase the effective ε to as high as ε=0.9999.
[0030] While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments and alternatives set forth above, but on the contrary is intended to cover various modifications and equivalent arrangements included within the scope of the following claims.
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A method for synthesizing a long, error-corrected DNA construct is disclosed. In the method, error-containing subregions of a long DNA sequence are replaced by repair oligonucleodides that are short enough that the probability of any one of them containing an error is less than one. Repeated repair cycles lead to a long DNA construct with very few remaining errors.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a continuation application of U.S. application Ser. No. 11/682,889 entitled “Method for Determining Connection Status of Wired Network,” filed on Mar. 7, 2007, now allowed, the disclosure of which is incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to wired networks, and more particularly, to a method for determining the connection status of a wired network.
BACKGROUND
[0003] An Ethernet network can usually support a variety of communicating bit rate modes, such as: 10 Mbps mode, 100 Mbps mode, and 1 Gbps mode.
[0004] Furthermore, two Ethernet networks can communicate with each other through the coupling of twist pairs. Under the 10 Mbps and 100 Mbps modes, two Ethernet networks can work properly by simply coupling two twist pairs between the two Ethernet networks; however, under a 1 Gbps mode, four twist pairs have to be coupled between the two Ethernet networks in order to make the two Ethernet networks work properly.
[0005] FIG. 1 is a diagram illustrating a prior art wired network. The wired network 100 is an example of the above-mentioned Ethernet network. The wired network 100 comprises a first network device 110 and a second network device 150 . Both the first network device 110 and the second network device 150 are capable to communicate under the 1 Gbps mode. Furthermore, both the first network device 110 and the second network device 150 can support communication below 1 Gbps, which is 10 Mbps or 100 Mbps. The first network device 110 comprises a first set of connection ends 120 (which comprise a first connection end 122 and a second connection end 124 ) and a second set of connection ends 130 (which comprise a third connection end 132 and a fourth connection end 134 ). Similarly, the second network device 150 comprises a first set of connection ends 160 (which comprise a first connection end 162 and a second connection end 164 ) and a second set of connection ends 170 (which comprise a third connection end 172 and a fourth connection end 174 ). Under the 1 Gbps mode, the four connection ends 122 , 124 , 132 , 134 of the first network device 110 have to couple to the four connection ends 162 , 164 , 172 , 174 of the second network device 150 through a pair of twist pairs, then the first network device 110 and the second network device 150 can communicate with each other properly.
[0006] More precisely, when the wired network 100 starts to establish a data transmission channel, the first network device 110 and the second network device 150 will first utilize the first set of connection ends 120 and 160 to mutually transmit the link pulse to confirm the communication ability of both devices. When both devices are confirmed to have communication ability under the 1 Gbps mode, and the first network device 110 is assumed to serve as the first network device and the second network 150 is assumed to serve as the second network device. The first network device 110 then utilizes the first and second set of connection ends 120 , 130 to transmit an idle pattern to the first and second set of connection ends 160 , 170 of the second network device 150 . If the second network device 150 successfully receives the idle pattern from the first and second set of connection ends 160 , 170 , then the second network device 150 also can utilize the first and second connection ends 160 , 170 to transmit the idle pattern to the first and second set of connection ends 120 , 130 of the first network device 110 . Then, the first and second network devices 110 , 150 can establish communication under the 1 Gbps mode.
[0007] However, for the wired network 100 , the physical communicating path between the first network device 110 and the second network device 150 may not conform to the requirement of the 1 Gbps mode. For example, one possible situation is when the first set of connection ends 160 of the second network device 150 is correctly coupled to the first set of connection ends 120 of the first network device 110 , but the second set of connection ends 130 of the first network device 110 is not correctly coupled to the second set of connection ends 170 of the second network device 150 . Therefore, in the above-mentioned situation, although the first and second network devices 110 , 150 can utilize the first set of connection ends 120 and 160 to confirm that both connection ends have communication ability with each other under 1 Gbps mode, the second set of connection ends 130 and 170 are not coupled correctly. Therefore, the first and second network devices 110 , 150 still cannot establish the real 1 Gbps communication with each other. Furthermore, at the mean time, the first and second network devices 110 , 150 will keep trying to establish the communicating mode of 1 Gbps mode, but will not succeed due to the incorrect connection.
SUMMARY
[0008] Therefore, one of the objectives of the present invention is to provide a method for determining the connection status of a wired network to resolve the above-mentioned problem.
[0009] One of the objectives of the present invention is to provide a method for determining the connection status of a wired network to determine the communicating mode of the wired network according to the status of the communicating path.
[0010] These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
[0012] FIG. 1 is a diagram illustrating a prior at wired network.
[0013] FIG. 2 is a flow chart of an operation of a first network device according to an embodiment of the present invention.
[0014] FIG. 3 is a flow chart of an operation of a second network device according to an embodiment of the present invention.
DETAILED DESCRIPTION
[0015] The method of the present invention can be utilized in the wired network 100 as shown in FIG. 1 , and it is assumed in the following description that the first and second network devices 110 , 150 are capable to communicate under 1 Gbps mode.
[0016] FIG. 2 is a flow chart of the operation of the first network device 110 according to an embodiment of the present invention. First, in the step of 210 , the first network device 110 utilizes the first set of connection ends 120 to mutually transmit the link pulse with the second network device 150 in order to confirm the communication ability between the network devices 110 and 150 . Meanwhile, as the first set of connection ends 120 and 160 are coupled with each other, the first network device 110 confirms that the second network device 150 has communication ability under 1 Gbps mode. In step 220 , the first network device 110 utilizes the first and the second set of connection ends 120 , 130 to transmit the idle pattern. In step 230 , the first network device 110 checks whether the first and second set of connection ends 120 , 130 have received the signal. As the first and second set of connection ends 120 , 130 of the first network device 110 are correctly coupled to the first and second set of connection ends 160 , 170 of the second network device 150 , the second network device 150 can correctly receive the idle pattern. Similarly, the second network device 150 also utilizes the first and second set of connection ends 160 , 170 to transmit the idle pattern. Therefore, if the first network device 110 detects that both the first and second set of connection ends 120 , 130 of the first network device 110 have received the signal, then the first network device 110 can proceed to step 250 to confirm that the path is correct.
[0017] If the second set of connection ends 130 of the first network device 110 are not coupled to the second set of connection ends 170 of the second network device 150 correctly, then the second network device 150 will not receive the idle pattern correctly, and therefore the second network device 150 will not return the idle pattern through the first and the second set of connection ends 160 , 170 . However, as the second set of connection ends 130 is not coupled to the second set of connection ends 170 correctly, when the first network device 110 transmits the idle pattern, the signal transmitted by the second set of connection ends will be reflected. Therefore, even though the second network device 150 does not return the signal, the first network device 110 will detect that the second set of connection ends 130 of the first network device 110 has received the signal (reflected signal), and detects that the first set of connection ends 120 of the first network device 110 has not received the signal. Meanwhile, the first network device 110 proceeds to step 260 , and determines that the second set of connection ends of the first network device 110 are not coupled to the second set of connection ends of the second network device 150 correctly, and disables the communication ability under 1 Gbps mode of the first network device 110 . After step 260 , the first network device 110 can re-try establishing connectivity with the second network device 150 while the communication ability under 1 Gbps mode is disabled. If the first network device 110 and the second network device 150 have established the communicating mode of the 10 Mbps mode or the 100 Mbps mode, then the first network device 110 can cancel the disable order of the communicating mode of the 1 Gbps mode (i.e. un-disable the communication ability under 1 Gbps mode of the first network device 110 ). Therefore, once the second set of connection ends 130 are coupled to the second set of connection ends 170 correctly, the communicating mode of 1 Gbps can then be set.
[0018] FIG. 3 is a flow chart of the operation of the second network device 150 according to an embodiment of the present invention. First, in the step 310 , the second network device 150 utilizes the first set of connection ends 160 to mutually transmit a link pulse with the first network device 110 to share the communication ability between the network devices 150 and 110 . Meanwhile, as the first set of connection ends 160 and 120 are coupled with each other, the second network device 150 confirms that the first network device 110 has communication ability under 1 Gbps mode. In step 320 , the second network device 150 checks the first and the second set of connection ends 160 , 170 to determine if the first and the second set of connection ends 160 , 170 have received the signal. As the first and second set of connection ends 160 , 170 of the second network device 150 are correctly coupled to the first and second set of connection ends 120 , 130 of the first network device 110 , the second network device 150 can correctly receive the idle pattern transmitted by the first network device 110 . Therefore, if the second network device 150 detects that both the first and second set of connection ends 160 , 170 of the second network device 150 have received the signal, then the second network device 150 can proceed to step 340 to confirm that the path is correct. Then, the second network device 150 returns the idle pattern to the first network device 110 and shares the communicating mode of 1 Gbps with the first network device 110 .
[0019] If the second set of connection ends 170 of the second network device 150 are not coupled to the second set of connection ends 130 of the first network device 110 correctly, then the second network device 150 can only receive the signal at the first set of connection ends 160 correctly, while the second set of connection ends 170 will not receive the signal correctly. Therefore, if the second network device 150 detects that the first set of connection ends 160 of the second network device 150 receive the signal, and the second set of connection ends 170 do not receive the signal, then the second network device 110 can proceed to step 350 . Then the second network device 110 determines that the second set of connection ends 170 of the second network device 110 are not coupled to the second set of connection ends 130 of the first network device 110 correctly, and disables the communication ability under 1 Gbps mode. After the step 350 , the second network device 150 can re-try establishing connectivity with the first network device 110 while the communication ability under 1 Gbps mode is disabled. If the second network device 150 and the first network device 110 have established the communicating mode of the 10 Mbps mode or the 100 Mbps mode, then the second network device 110 can cancel the disable order of the communicating mode of the 1 Gbps mode (i.e. un-disable the communication ability of communicating under 1 Gbps mode of the second network device 150 ). Therefore, once the second set of connection ends 130 are coupled to the second set of connection ends 170 correctly, the communicating mode of the 1 Gbps mode can then be set.
[0020] Please note that those skilled in this art will readily know that, although the above-mentioned first and second network devices 110 , 150 are the first network device and the second network device respectively, the first and second network devices 110 , 150 can also be the second network device and the first network device respectively. In other words, when the first and second network devices 110 , 150 are the second network device and the first network device respectively, the first network device 110 decides the state of network connectivity according to the method as shown in FIG. 3 ; and the second network device 150 decides the state of network connectivity according to the method as shown in FIG. 2 . Furthermore, determining whether the first and second network devices 110 , 150 are the first and second network devices respectively, or the second and first network devices respectively is prior art, and the detailed description is therefore omitted here for brevity.
[0021] According to the above-mentioned disclosure, when the connection between the first and second network devices 110 , 150 conforms to the requirements of 1 Gbps mode (i.e. both devices coupled with each other through four twist pairs correctly), the first and second network networks 110 , 150 can share the network communicating of 1 Gbps mode. When the connection between the first and second network devices 110 , 150 does not conform to the requirements of 1 Gbps mode (i.e. both devices are coupled with each other through four twist pairs incorrectly), the first and second network networks 110 , 150 will disable the communication ability under 1 Gbps mode, and try to establish the connection mode of 10 Mbps mode or 100 Mbps mode with each other.
[0022] Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
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A method applied to a wired network including a first network device and a second network device is disclosed. The first and second network devices each include a first set of connection ends and a second set of connection ends. Firstly, the first network device transmits a specific signal pattern through its first set and second set of connection ends. Then, the first network device detects whether a signal is received at its first set and second set of connection ends. If it is determined that a signal is not received at the first set connection ends while a signal is received at the second set connection ends, the first network device determines that its second set of connection ends is not correctly coupled to the second set of connection ends of the second network device.
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FIELD OF THE INVENTION
[0001] The present invention relates to the drying of materials using a heat pump or heat integrated dehumidifier system to move energy to evaporate liquid from wet material. It has particular application to the drying of materials in a nominal paste, wet liquor or aggregate form but is also well suited for numerous other drying processes.
BACKGROUND TO THE INVENTION
[0002] Most pastes and similar wet liquors dried on an industrial scale are currently dried by systems operating on a heat-and-vent principle where ambient air or other drying gas is heated by indirect contact with steam or by some other high temperature heat source, passed over or through the paste, liquor or other material to be dried, and vented back to the atmosphere. This process is often relatively rapid but energy inefficient and can emit a large vapour plume that is undesirable in many cases.
[0003] The problem of the highly prominent vapour plume is associated with the warm wet drying gas vented from the unit. In some implementations, these emissions can contain volatile organic products, including hazardous air pollutants. Even when it does not contain polluting components, the vapour plume is a clear indication of industrial activity that has become undesirable in many situations. This plume is also a problem in that it prevents the recovery of the moisture removed from the process which may have value in certain instances. This problem can be addressed by either removing the condensable material from the exhaust stream before it is exhausted to the environment or in preparation to recirculate it back through the drying system. Although these methods are known in the art, it is often expensive to implement such processes.
[0004] One way to improve the efficiency problem for existing heat and vent processes is to recover some of the heat present in the drying gas after it has taken up moisture from the material being dried. This is known in the art and has led to several patents on various ways to recover this heat. One such patent, U.S. Pat. No. 4,466,202 by Merten, proposes a variation on the commonly used vapour recompression process. In Merton's process, a drying gas is recirculated through the drier and the moisture vapour taken up by the drying gas is separated out by a semi-permeable membrane. This moisture vapour is then compressed and condensed with the heat of condensation used to either heat the incoming drying gas or the material being dried before it is removed from the process.
[0005] Although Merton's process can improve efficiency and eliminate the vapour plume, there are several significant disadvantages. The first is that the membrane system for separating the moisture vapour from the drying gas is expensive and causes a significant pressure drop in both the moisture vapour and drying gas streams which must be overcome by compressor systems. The second is that the resulting low pressure of the permeate vapour stream will require a large volume capacity compressor which significantly increases the cost of the process. A third disadvantage is that the process is constrained by the requirement that the compressor and heat recovery system be specifically designed around the thermodynamic and refrigeration properties of the type of moisture being removed from the process and must deal with any less than optimum behaviours of that moisture species.
[0006] Heat pump systems have also been used to improve the efficiency of the drying process yet avoid this limitation by the thermodynamic refrigeration properties of the moisture being removed. U.S. Pat. No. 4,134,216 by Stevens proposes a heat pump system with a closed loop refrigerant cycle and a closed loop drying gas cycle where the heat pump continuously recovers the heat of condensation from the moisture laden drying gas and recycles it into the moisture lean drying gas before it contacts the material being dried. U.S. Pat. No. 4,247,991 by Mehta proposes a similar process with a supplemental drying gas desiccant added to generate further improvement. Although both of these processes improve the efficiency and eliminate the vapour plume in a more flexible way, they both have the disadvantage of returning heat to the process through the drying gas medium. This requires a large area for heat exchange, a large flow or high temperature for the drying gas, and a higher pressure drop or inefficient heat pumping to and from the drying gas as it moves through the process.
[0007] Another heat pump drying system is described in U.S. Pat. No. 5,537,758 by Guarise. This apparatus seeks to speed up a heat pump based drying process similar to the one described in U.S. Pat. No. 4,134,216 by adding a pre-drying chamber. The heat of evaporation to drive this pre-drying chamber is either supplied directly to the material being dried by a high frequency electric field in an induction heating configuration similar to a microwave oven or through a separate hot air stream which is heated by a source separate from the heat pump circuit. Although such a system should produce a faster overall drying rate, it will be extremely inefficient and expensive in its operation of the pre-drying chamber. These disadvantages result from the lower efficiency of high frequency induction heating in this environment and the high flows or high temperatures required for the drying gas (air) to provide the large heat of evaporation for the moisture being removed.
[0008] A non-heat pump based drying process and apparatus proposed by Stevens and Peeters in U.S. Pat. No. 5,600,899 identifies another method to improve the uptake of the heat of evaporation by the material being dried. Their system also uses a heated drying gas to supply this heat of evaporation but employs a gas permeable conveyor belt to transport the material being dried. In this way, the heated drying gas can more effectively transfer heat to the material being dried. However, as with the other heated gas methods, this process requires significant fan power to overcome the pressure drop across the permeable belt and either a high temperature gas or a high flow of gas to transport the required amount of heat to evaporate the moisture. As a result, the process and apparatus proposed in U.S. Pat. No. 5,600,899 will be relatively costly and inefficient.
[0009] In U.S. Pat. No. 5,862,609, Steven and Peters propose a variation on their U.S. Pat. No. 5,600,809 process and system which is more amenable to use of a heat pump. This variation can more readily take advantage of the improved efficiency provided by a heat pump system by way of its multiple stages of closed loop drying gas circulation through their permeable conveyors. However, the high fan power costs associated with moving the large amounts of drying gas required will leave it with a cost and efficiency disadvantage.
[0010] Thus, although there have been numerous attempts to improve the efficiency and effectiveness of drying pastes, liquors and aggregate materials, there is still opportunity for further improvements.
SUMMARY OF THE INVENTION
[0011] It is an object of the present invention to provide an improved drying process and/or an apparatus for drying by means of a heat integrated and/or heat pumping process and/or apparatus.
[0012] In one aspect the present invention may be said to consist of a heat pump or heat integrated apparatus operable in a drying apparatus with the heat pump evaporator or cold heat exchanger in primary thermal contact with the drying gas medium after said drying gas medium has taken up moisture from the material being dried and the heat pump condenser or hot heat exchanger in primary thermal contact with the material being dried and with both the drying gas medium and any heat pump refrigerant in nominally closed loop circulation paths.
[0013] In another aspect the present invention may be said to consist of a heat pump and drying apparatus including a drying chamber and a heat exchange apparatus, wherein the heat exchange apparatus includes a colder heat pump evaporator or heat integrated heat exchanger(s) and a hotter heat pump condenser or heat integrated heat exchanger(s) arranged such that during operation, the colder heat exchanger(s) substantially exchanges heat with the moisture rich drying gas stream, and the hotter heat exchanger(s) substantially exchanges heat with the material being dried rather than the moisture lean drying gas stream.
[0014] In another aspect the present invention may be said to consist in a heat pump driven drying process, wherein the heat exchange is performed though a colder heat pump evaporator or heat integrated heat exchanger(s) and a hotter heat pump condenser or heat integrated heat exchanger(s) arranged such that during operation, the colder evaporator or heat integrated heat is exchanged substantially with the moisture rich drying gas stream, and the hotter condenser or heat integrated heat is exchanged substantially with the material being dried rather than the moisture lean drying gas stream.
[0015] The hotter and colder heat exchange apparatus are primarily driven by the heat pump cycle through its respective condenser and evaporator. However, both heat exchange apparatus may utilise other integrated heat exchange technology. For example, other heat sinks and sources may be used to augment or replace the heat pump evaporator and condenser.
[0016] Preferably, the invention provides a higher efficiency process through the more direct heat exchange with the material being dried as well as a reduced capital cost process by way of the reduced drying gas requirements. These reduced drying gas requirements will come from the fact that the drying gas will have a higher capacity to take up moisture relative to its capacity to provide the heat needed to take up that moisture.
[0017] A preferred embodiment of the invention consists of a heat pump drying process and apparatus configured so that the heat pump condenser and evaporator are located entirely within a nominally enclosed chamber and work effectively with the primarily closed loop recirculating air-flow (or other drying gas medium). The method and apparatus of the invention conducts the drying gas cooling and moisture condensation heat exchange at the heat pump evaporator and does not directly heat the drying gas stream in any substantial way but instead provides the primary heat for drying from the heat pump condenser to the material being dried rather than through intermediate heat exchange with the drying gas stream as is done with conventional heat pump dehumidifier drying systems.
[0018] In optional embodiments employing heat integrated processes and apparatus, it is possible to use a waste heat source to supplement or replace the heat pump condenser and a waste heat sink such as cooling water to supplement or replace the heat pump evaporator.
[0019] In the preferred embodiment of the invention, in each pass through the heat pump system, all or part of the drying gas passes over the heat pump evaporator where some of the moisture is condensed out and heat is recovered from the drying gas stream. The drying gas stream then primarily takes up heat through contact with the material being dried and mixing with the moisture vapour evaporating from the material being dried rather than more directly through heat exchange with the heat pump condenser.
[0020] As with other existing heat pump systems, for low humidity operation, the drying capacity and efficiency of the invention can be optionally enhanced by recovering sensible cooling at the evaporator using a pair of liquid coupled or heat-pipe coupled heat exchangers at the evaporator (Blundell, 1979).
[0021] As those skilled in the art will appreciate, the process and apparatus of this invention will provide benefits to drying many different materials. These materials include but are not limited to sewage sludge, meat and vegetable matter processing streams and wastes, dairy processing streams and wastes, paper, bricks, gypsum, plaster board, textiles, china clay, fertilizer, dye stuffs, tiles, pottery, grain, nuts, seeds, fruits, bio-processing waste, etc.
[0022] The process and apparatus of this invention are also amenable to various drying gas mediums. Although the preferred embodiment for the invention is with air as the drying gas, the process and apparatus can be configured to use O 2 -free air, nitrogen, argon, oxygen, or any other gaseous medium to take up the moisture from the materials to be dried and condense that moisture out of the system through the heat pump evaporator as noted in (Chen, Bannister, McHugh, Carrington, Sun, 2000) for other more traditional heat pump drying systems. As with other existing heat pump systems, the invention requires means for rejecting excess heat from the drying chamber. This may include full time or periodic venting of a sub-stream of the drying gas, cooling the drying gas entering the evaporator, cooling any make-up or purge drying gas entering or leaving the apparatus, sub-cooling the liquid heat pump refrigerant leaving the condenser, cooling the heat pump refrigerant leaving the compressor, or cooling and partially or wholly condensing the high-pressure refrigerant for purposes of control.
[0023] Also, although the system is preferentially focussed on water removal, it can also be configured to remove other vaporisable and condensable liquids from the material to be dried such as various organic solvents to be recovered from solvent based processing steps.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Preferred embodiments of the invention will be described with reference to the accompanying drawings, of which:
[0025] FIG. 1 shows a basic heat pump process flow diagram applicable to this invention,
[0026] FIG. 2 shows a preferred heat exchanger and drying chamber configuration with a belt system for conveying the material to be dried, and
[0027] FIG. 3 shows a preferred condenser heat exchanger configuration with a belt system for conveying the material to be dried.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] The present invention is a process and apparatus to improve the heat pump based or heat integrated drying of liquors, pastes and other similar free flowing materials. A preferred embodiment of the invention involves exchanging heat between the heat pump evaporator and the moisture laden drying gas stream to partially condense and remove the moisture from the drying gas stream and involves exchanging heat between the heat pump condenser and the material being dried nominally without directly heating the drying gas stream in any substantial way except through contact with the material being dried and through mixing with the moisture vapour evaporating from the material being dried.
[0029] The following description of the process and apparatus of this invention, by way of example only and with reference to the accompanying drawings in the accompanying figures, indicates the presently preferred embodiments of the invention.
[0030] Referring to FIG. 1 , the basic heat pump cycle is put forward with the primary sequence of processes for the refrigerant cycle of compression 11 , condensation 12 , expansion 13 and evaporation 14 with the drain 15 to indicate the removal of condensed liquid from the drying gas stream (not shown) at the evaporator 14 . The heat pump system is controlled by integrated control unit 16 through signals from one or more sensors 17 and though one or more actuation devices 18 . The designation of item 18 as a compressor suction control valve is simply one option for control actuation.
[0031] In the context of a dehumidifier drying system, referring to FIG. 2 , the heat pump compressor (not shown) operates to move heat from the lower temperature evaporator heat exchanger (or exchangers) 36 to the higher temperature condenser heat exchanger or exchangers 29 , 30 and 31 . The heat pump evaporator 36 acts to remove heat from the drying gas 33 and condenser heat exchangers 29 , 30 and 31 act to provide heat to the material being dried.
[0032] The drying gas is primarily recirculated through the system. Moisture laden drying gas stream 33 passed over heat pump evaporator heat exchanger 36 which cools and partially condenses moisture vapour from the drying gas and drains that condensed moisture from the system by gravity or other appropriate mechanism (not shown). The moisture lean drying gas stream 34 then is channelled over the material being dried, which is spread out over a belt conveyor system 23 , 24 and 25 . There the drying gas takes up moisture evaporating from the material being dried and then as stream 35 optionally provides heat to the incoming material being dried through exchanger 37 before it recycles again through the system guided by various internal baffles and plates such as item 39 . It can be appreciated by those skilled in the art that the drying gas flow need not be recirculated in a rigorously closed loop. It is readily possible within the scope of the invention to have various drying gas purge and makeup streams as is appropriate to the specific drying application.
[0033] Since the heat input to the system comes primarily through the material being dried, any temperature drop experienced by the drying gas in other parts of its cycle through the system can be recovered as the drying gas passes over the material being dried and actually receives heat from both contact with the material and from uptake of the heated moisture vapour coming off the material being dried. This is the opposite of existing systems where the drying gas provides heat to the material being dried. Since the sensible heat taken up by the drying gas is small relative to the total heat of evaporation provided by the heat pump condenser, any losses from this reversal are similarly small. As a consequence, the drying gas flow needed to take up the moisture is much lower than it would be if it also had to provide the heat of evaporation to the material being dried which significantly reduces wasteful dry gas fan power or the required temperature difference of the drying gas relative to existing systems. Thus the combination of effects leads to an overall net process efficiency improvement relative to existing systems.
[0034] The material being dried enters the system as stream 21 and is optionally preheated by the moisture laden drying gas stream 35 . It is then distributed into a high surface area configuration, which in this preferred embodiment is onto a set of moving belt conveyors 23 , 24 and 25 . In the preferred configuration shown, the conveyor moves the material being dried from left to right in counter current flow to the drying gas. But, it does not materially affect the invention if the movement of the material being dried were in co-current flow with the drying gas stream. The heat pump condenser 29 , 30 and 31 acts to provide the heat of evaporation to vaporise the moisture from the material being dried primarily by conduction, preferentially through a tube, plate and belt configuration shown in more detail in FIG. 3 . As the material being dried moves along the conveyor and gives off moisture during the drying process, it passes through an optional set of agitation devices 26 , 27 and 28 which can act to break up any moisture resistant skin that may form during drying. Once the material is sufficiently dry, it leaves the system as stream 38 .
[0035] The details of one preferred method for providing the heat from the heat pump condenser more directly into the material being dried rather than through the drying gas medium are shown in FIG. 3 . The refrigerant tubes of the heat pump condenser are shown as item 50 . The condensing refrigerant transfers heat through the heat exchanger tube walls and into an optional dispersion plate 51 . In this embodiment, the dispersion plate is made from a high heat transfer material such as copper or aluminium. In cases where corrosion may be a problem, a thin sheet or film of corrosive resistant material may optionally overlay any dispersion plate. In the embodiment shown, the heat from the heat pump condenser is then transferred through a conductive conveyor 52 to the material being dried. As those who are skilled in the art are aware, the high thermal conductivity of the conveyor and dispersion plate significantly affect the efficiency of the process and should be maximised. The material being dried 53 is spread on the conveyor 52 at the left and dries as the conveyor moves in a clockwise direction before it leaves the conveyor as dry material 54 . In this embodiment, the material being dried will be spread such that it has good thermal contact with the conveyor or the condenser heat exchanger tubes if a conveyor and dispersion plate are not needed.
[0036] It can be appreciated by those skilled in the art that other waste heat sources or sinks may be available at low cost in certain process environments. In these situations, for the case where the heat pump system is augmented or replaced by an alternate high temperature heat source and lower temperature heat sink, the condensing duty from the heat pump refrigerant working fluid is augmented or replaced by the high temperature heat source in the heat exchange system and the evaporating duty from the heat pump refrigerant working fluid is augmented or replaced by the lower temperature heat sink in the heat exchange system.
[0037] It can also be appreciated by those skilled in the art, that additional components specific to the product being dried, such as auxiliary heaters for sterilization can be readily added to the process and apparatus of the invention without materially changing the invention.
[0038] Similarly there are various methods and apparatus that can be added to the process and apparatus of this invention to reject any excess heat from the overall process to the ambient environment without materially changing the invention. These include but are not limited to venting a sub-stream of drying gas, pre-cooling the drying gas entering the evaporator, cooling any make-up or purge drying gas entering or leaving the heat pump apparatus, sub-cooling the liquid heat pump refrigerant, de-superheating the heat pump refrigerant leaving the compressor, or partially or wholly condensing the high-pressure refrigerant for purposes of control.
[0039] As with other heat pump systems, additional methods of heat recovery may be optionally applied to the invention without material change to the invention. For instance, it is possible to include the capacity for reclaiming sensible cooling at the evaporator using, for example, either a pair of liquid coupled heat exchangers, or by means of heat-pipe coupled heat exchangers. Also, it will be noted that some heat may be added to the recirculating drying gas stream from the heat pump circuit to fine tune and control the process without material change to the invention.
[0040] As those skilled in the art will appreciate, the process and apparatus of this invention will provide benefits to drying many different materials. These materials include but are not limited to sewage sludge, meat and vegetable matter processing streams and wastes, dairy processing streams and wastes, paper, bricks, gypsum, plaster board, textiles, china clay, fertilizer, dye stuffs, tiles, pottery, grain, nuts, seeds, fruits, bio-processing waste, etc.
[0041] The process and apparatus of this invention are also amenable to various drying gas mediums. Although the preferred embodiment for the invention is with air as the drying gas, the process and apparatus can be configured to use O2-free air, nitrogen, argon, oxygen, or any other gaseous medium to take up the moisture from the materials to be dried and condense that moisture out of the system through the heat pump evaporator. As with other existing heat pump systems, the invention may require means for rejecting excess heat from the drying chamber. This may include desuperheating, condensing or sub-cooling refrigerant leaving the compressor and rejecting heat to the environment. Alternatively the drying gas may be precooled as it enters the evaporator or the dehumidifier more generally.
[0042] Also, although the system is preferentially focussed on water removal, it can also be configured to remove other vaporisable and condensable liquids from the material to be dried such as various organic solvents to be recovered from solvent based processing steps including painting.
[0043] Although the figures show a preferred embodiment for a conveyor belt material handling system, it can readily be appreciated that minor changes to the drying chamber configuration can be made to facilitate other methods of conveyance such as wiped film systems, in other drying gas mediums and for removing liquids other than water.
[0044] In the preferred embodiment for drying an biological paste for a typical feed with 25% solids content (300% moisture content dry basis) and drying to an 80% solids content (25% moisture content dry basis), the nominal conditions are summarised in Table 1:
TABLE 1 Biological Paste Drying Example Parameter Range Dry bulb temperature of drying gas (average 35-70 C. over the system) Wet bulb temperature of drying gas (average 20-65 C. over the system) Drying gas velocity over the material being 1-5 m/s dried Approach temperature in heat pump condenser 2-25 C. Approach temperature in heat pump evaporator 2-45 C. Drying gas temperature drop across evaporator 3-35 C. heat exchanger Condenser temperature heat pump fluid side 40-85 C. Evaporator temperature heat pump fluid side 20-65 C.
[0045] Computational models of the efficiency of organic paste drying in a conventional heat pump system with drying gas heating and cooling and in a conventional combustion heat driven system were compared to similar models for the efficiency of paste drying using a preferred embodiment of the invention. The case considered was for a wet paste feed containing 30% solids on a total mass basis with a dry product of 83% solids on a total mass basis for a system capable of removing 390 kg/hour of moisture. The results are summarised in Table 2.
TABLE 2 The Existing Thermal Existing Heat Invention System Pump Systems Combustion Heat 0 380 kW 0 Electrical Power 42 kW 50 kW 130 kW Estimated annual cost $33,600 $161,600 $104,000 @ $0.10/kWh electric & $0.04/kWh combustion Estimated Operating $128,000 $70,400 Savings $ per year for the invention relative to other existing options
[0046] Comparison of the two processes shows that the overall drying efficiency is significantly higher when the heat of evaporation is directly supplied to the material being dried by conduction rather than by the drying gas stream. Thus the invention achieves a substantial performance benefit relative to the prior art heat pump drying systems.
[0047] It will be appreciated that the invention is not restricted to the particular embodiments and modifications described above and that numerous modifications and variations can be made without departing from the scope of the invention.
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A process and apparatus for drying pastes, liquors and aggregate materials by means of a heat integrated and/or heat pumping process and/or apparatus is disclosed. This includes a heat pump or heat integrated apparatus operable in a drying apparatus with the heat pump evaporator ( 36 ) or cold heat exchanger in primary thermal contact with the drying gas medium ( 33 ) after said drying gas medium ( 33 ) has taken up moisture from the material being dried ( 35 ) and the heat pump condenser ( 14 ) or hot heat exchanger ( 36 ) in primary thermal contact with the material being dried and with both the drying gas medium ( 33 ) and any heat pump refrigerant in nominally closed loop circulation paths ( 22 ). This process and apparatus may provide improved efficiency and reduced costs by reducing the required flow of drying gas through the system since that drying gas is no longer the primary means for supplying heat to the material being dried.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of the present invention relates generally to hot water heaters and more particularly to instantaneous demand hot water heaters.
2. Background Art
The present inventor is familiar with the following three U.S. patents which are hereby fully incorporated herein for all purposes by this specific reference:
______________________________________U.S. Pat. No. Inventor______________________________________1,901,761 Wilmer E. McCorquodale2,974,650 Alan B. McCorquodale3,320,935 Alan B. McCorquodale______________________________________
By instantaneous demand is meant a hot water heater that provides an output of heated water in response to user demand. The water is heated while flowing through coils or tubes rather than heating a tank or reservoir filled with water as in conventional household water heaters. The latter arrangement is relatively inefficient in use of energy in requiring the heating and maintaining a large volume of water in heated readiness. In addition, the tank type heater is not suitable for long periods of continuous high consumption use and is not responsive to intermittent demand. The capability to respond rapidly to the heated water use or demand results in the instantaneous demand nomenclature.
U.S. Pat. No. 1,901,761 is entitled "Hot Water Heater Attachment" and discloses four embodiments of an instantaneous demand responsive gas fired hot water heater. All four embodiments disclosed utilize an external recirculation flow casing for circulating the heated water with the water temperature sensing thermostat positioned in the external casing for controlling gas flow to the burner. In all four embodiments the cold water is injected into the external casing for circulation past the water temperature sensing thermostat prior to passage into the heating coil. When flow of water is discontinued through coils and due to the thermostat location, the burner continues operation until sufficient heated water is recirculated down the recirculation casing to displace the cold water and contact the thermostat.
U.S. Pat. No. 2,974,650 is entitled "Water Heater With Side Wall Venting Means." The disclosed gas fired water heater is particularly suited for use in automobile trailers as the flue gas is safely discharged through the heater side wall. The gas burner heats an ovate reservoir tank having the thermostat located adjacent the bottom of the tank. The disclosed conventional reservoir heater is not of the instantaneous demand type, but is rather of the conventional type in sensing the water temperature in the tank.
U.S. Pat. No. 3,320,935 is an improvement of U.S. Pat. No. 2,974,650 and is entitled "Water Heater With Side Wall Air Supply and Venting Means." The disclosed hot water heater insures that all flow of air is directly to the burner and then as flue gas outwardly through the side wall vent.
3. Objects of the Present Invention
An object of the present invention is to provide a new and improved hot water heater.
A further object is to provide a new and improved instantaneous demand gas fired hot water heater.
Yet another object is to provide a new and improved instantaneous demand hot water heater that is sensitive in response to demand usage and economical in operation.
SUMMARY OF THE INVENTION
The present invention relates to new and improved instantaneous demand gas fired hot water heater. The water is heated by the gas burner when flowing upwardly in a heating coil assembly from a lower header to an upper header. The heated water temperature sensing thermostat is located in the upper or hot water discharge header casing adjacent the cold water inlet. The thermostat senses the outlet header water temperature to control the burner operation to insure proper temperature of the heated water effluent. Upon user demand, the proper temperature heated water is discharged while the cold water make up initially contacts the thermostat to immediately activate the burner element. The cold water then flows immediately from the upper header into the recycle or recirculation casing to the lower header. Upon termination of hot water demand only a small portion of the cold water needs to be displaced from the upper header into the recirculation casing before the heated water temperature is sensed by the thermostat and burner operation terminated. The internal recycle line or casing between the upper and lower headers also enables sufficient circulation of the heated water with the heater water outlet closed to prevent localized waste overheating with attendant loss of efficiency. The thermostat arrangement provides enhanced efficiency by shutting off the burner with colder water in the recycling casing and thereby avoiding unnecessary heating of the water.
BRIEF DESCRIPTION OF THE DRAWINGS
The FIGURE is a side view, in section, of an instantaneous demand hot water heater apparatus constructed in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The hot water heater apparatus, generally designated A in the FIGURE, of the present invention is of the instantaneous demand responsive type for providing hot water at a relatively high operating pressure. The disclosed water heating apparatus is not intended or designed for use as an internal steam generator, but as only a water heater. However, when the heated high pressure water is discharged, the water may flash to steam under certain conditions. Such instantaneous demand hot water heaters have a number of useful purposes one of which is providing a supply of high pressure hot water (near, but not at the boiling point) for a desired intended use such as carpet cleaning equipment.
The hot water heater apparatus A is provided with a rigid steel substantially cylindrical shell assembly 10 which forms a relatively light and compact unit. The shell assembly 10 is provided with the suitable support ring or plurality of support legs 12a for positioning the shell assembly 10 a suitable distance above the floor or other selected support surface F. The shell assembly 10 is assembled using any desired securing means, but metal screws that enable disassembly are preferred.
The heater shell assembly 10 includes a substantially cylindrical outer steel shell 12 and an inner shell 14. The steel inner shell 14 is concentrically disposed within and spaced from the outer shell 10. The upper end of the outer shell 12 is closed by a disc shaped upper or outer roof 16 while the inner shell 14 is closed by a disc shaped inner roof 18 that is parallel to and spaced from the upper roof 16. The lower end of the outer shell 12 is closed by a bottom plate or lower closure member 20 which is secured to the heater support ring 12a.
The inner shell 14 is joined to the outer shell 12 at a circumferential seam 14a desired distance above the bottom plate 20. The space between the inner shell 14 and the outer shell is filled with a suitable high temperature insulation 22 prior to final assembly.
Extending through the inner roof 18 and outer roof 16 is a flue gas outlet 24 than enables the flue gas or combustion products to escape from the internal heating chamber 26. Disposed below the seam 14a is a suitable plurality of burner openings 28 formed in the outer shell 12 for enabling passage of combustion air into the heating chamber 26. An enlarged burner opening 30 enables installing and removal of a conventional gas burner assembly 32 from the heating chamber 26 as well as providing a passage for combustion air. The gas burner assembly 32 includes the conventional pilot light flame burner (not illustrated) for igniting the gas from the burner assembly 32 as well as a pilot flame sensing thermocouple as is known in the art.
Disposed within the shell assembly 10 is a water containing heating coil assembly 34 in which the temperature of the high pressure water is elevated to the desired temperature. The heating coil includes a suitable plurality (preferably three) of nested spiral seamless copper tubing coils 36, 38 and 40. The plurality of coils 36, 38 and 40 are arranged in a multiple lead arrangement to insure uniform exposure to the flame of the burner 32 for insuring substantially even heat transfer to the water in each of the coils 36, 38 and 40. Copper is preferably employed as a material of construction to enhance the heat transfer from the burner flame to the water as known in the art. The heating coil assembly 34 further includes an upper heated water header or outlet manifold 42 communicating with the coils 36, 38 and 40 as well as a lower water feed or inlet header or manifold 44 which also communicates with the spiral coils 36, 38 and 40. During water heating operations the water preferably flows or circulates from the lower manifold 44 upwardly through the parallel coils 36, 38 40 to the upper outlet manifold 42.
A heated water outlet 46 is provided in the upper manifold 42 for enabling discharge of the heated water as desired. In practice, the water outlet 46 is preferably connected to the point of use of the heated water where a suitable flow control valve (not illustrated) is located. Also communicating with the upper manifold 42 is the high pressure make up water inlet 48 for supplying make-up water to the hot water apparatus A as heated water is withdrawn through the outlet 46. The heater coil assembly 34 further includes a heated water recirculation casing or tube 50 disposed within the annular insulation 22 of the shell 10 that also communicates the upper header 42 and the lower header 44. The recirculation casing 50 enables thermal circulation of the heated water from the upper manifold 42 back to the lower manifold 44 to prevent localized overheating or boiling of the water when the heated water outlet 46 is shut in. In addition, the casing 50 is sized to provide the desired flow path for the incoming cold water 48 to flow directly from the inlet nozzle 48 into the casing 50 to the lower header 44 for a purpose to be described more fully hereinafter.
Protruding into the upper manifold 42 adjacent the recirculation casing 50 and water inlet 48 is a water temperature sensing element or thermostat 52 mounted on a conventional gas flow controller 54. The controller 54 is mounted with the upper manifold 42 by conventional threaded engagement at 54a as is well known in the art. The gas flow controller 54 is connected to a fuel gas supply line 56 and a gas outlet line 58 that is operably connected at the other end to the burner assembly 32 disposed within the heating chamber 26 below the heating coil assembly 34. The gas flow controller 54 serves to automatically control the flow of the gas from inlet line 56 through the connecting line 58 to the burner assembly 32 in the usual manner. The gas flow controller 56 also provides a fuel supply for the burner pilot light and a safety thermocouple to confirm proper operation of the pilot light (neither of which is illustrated) in the known manner.
The temperature sensing element 52 senses the temperature of the water in the upper manifold 42 adjacent the recirculation casing 50. When the water temperature in the upper manifold 42 falls below a preselected value set by water temperature controller adjustment 54b on the controller 54 the flow of fuel gas will be enabled to the burner 48. The gas flame will heat the high pressure water in the heating coils 36, 38 and 40 in the usual manner. As the heated water circulates or flows up the coils 36, 38 and 40 into the upper header 42 and on through outlet 46 for use, make up water will enter the upper header at water inlet 48. As the cold water inlet 48 is located radially across the tubular upper header 42 from the recirculation casing 50, the desired and designed flow path of the cold water from inlet 48 is across the header 42 into the recirculation casing 50. To achieve this flow path, the water inlet line 48 is made significantly smaller than the casing 50. The larger casing 50 offers less flow resistance to the cold water which is introduced into the header 42 at a relatively high velocity by the smaller inlet line 48. The velocity of the incoming cold water tends to guide flow directly into the aligned casing 50 after flowing about temperature sensing element 52. In flowing across the temperature sensing element 52, the decrease in temperature is immediately sensed and burner 32 operation activated by controller 54. Such arrangement provides for a (near instantaneous) burner response to the introduction of cold water resulting from hot water usage. When hot water demand terminates the cold water make up is also simultaneously and instantaneously terminated. The connections of the water heating coils 36, 38 and 40 with the upper header are disposed between the heated water outlet 46 and the temperature sensing element 52 to help prevent by-passing of cold water directly to the outlet 46. The temperature sensing element 52 will sense the higher temperature water and terminate the flow of the gas by the gas flow controller 54 as soon as the upper header 42 is filled by heated water when hot water use is terminated. Thus, when the demand of hot water at the outlet 30 is terminated only sufficient recirculation of the heated water to bring the temperature of the water in the upper manifold 46 to the desired temperature is required for burner 32 operation to be terminated by the valve controller 54 in response to the temperature by the temperature sensing element 52. When flow of heated water commences at outlet 46 the cold make-up water flows inwardly through inlet 48 across temperature sensing element 52 to the casing 50 in the predetermined preferred cold water pattern. In flowing to the casing 50 the cold water flows about the temperature sensing element 52 which senses the reduced water temperature and responsive thereto open the gas valve controller 54 to enable burner operation for heating water in the coils 36, 38 and 40. The cold water will circulate down the casing 50 to the lower header 44 where it will flow upwardly through the heating coils 36, 38 and 40 saving or absorbing the heat energy released by the burner 32.
By locating the temperature sensing element 52 in the upper manifold 42 in alignment with the water inlet 48 and the recirculation casing 52 a more responsive control of the instantaneous demand hot water heater apparatus A is provided which is also more efficient in use of fuel gas. When the heated water demand terminates, only sufficient water needs to be heated to displace the cold water from the upper manifold 42 before the temperature sensing element 52 senses the higher water temperature for terminating gas flow by the gas controller 54. At that point in time the water temperature in the casing 50 and lower manifold 44 may be substantially less than the predetermined temperature sensed by the temperature sensing element 52. In the prior art, the temperature sensing element 52 was positioned such that the water in the circulation tube 50 and in the lower manifold had to reach the predetermined temperature before burner operation was terminated. Such a delay in ending burner operation was an inefficient waste of fuel and resulted in some occasions in having to reheat the hot water. A more responsive arrangement is provided by the present invention which terminates burner operation faster in response to the termination to the heated water demand than that in the prior art. In addition, the recycling or recirculation of the heated water is minimized to further conserve energy.
The foregoing disclosure and description of the invention are illustrative and explanatory therof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.
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An instantaneous demand gas fired hot water heater apparatus having the water temperature sensing thermostat disposed in the upper hot water outlet header with the inlet flow of unheated water directed to flow in a preferred flow path across the temperature sensing element. The temperature sensing element location in the upper header of the heater provides an extremely sensitive and efficient burner control. Upon initial output demand of hot water the lower temperature of the unheated water is immediately sensed by the temperature sensing element to immediately commence burner operation. Upon termination of heater water demand, the heated water temperature is rapidly sensed by the temperature sensing element to promptly terminate the supply of the gas to the burner and minimize unnecessary heating of the water.
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FIELD OF THE INVENTION
[0001] The present invention relates to a method for in vitro molecular evolution of antibody function.
BACKGROUND OF THE INVENTION
[0002] WO98/32845, Söderlind et al. (1999), and Jirholt et al. (1998) describe the in vitro molecular evolution of antibody-derived proteins, by implanting naturally occurring complementarity determining regions (CDRs) into a defined and selected (“master”) framework, comprising the framework regions from the germline gene DP-47 of the V H 3 family. Oligonucleotide primers, based on the sequences encoding parts of the framework regions of DP-47 immediately flanking the CDRs, are used to amplify nucleic acid sequences encoding CDRs from a cDNA library prepared from peripheral blood B cells. Single stranded DNA from the amplification reaction is then combined with overlapping oligonucleotides which encode the remainder of the master framework in an overlap extension PCR reaction to produce full length sequences encoding VH antibody domains which each contain the framework regions of the DP-47 germline gene, and CDRs from germline genes of the V H 3 family.
[0003] This technique provides a valuable means of increasing diversity in antibody libraries (e.g. phage display libraries), particularly as it allows recombination of CDR1 and CDR2, which are normally linked in vivo and do not undergo recombination during germline gene rearrangement.
[0004] Moreover, the CDRs have been proof-read in vivo and are unlikely to be immunogenic, providing an advantage over artificially mutated CDR sequences. Also, the master frameworks utilised (from germline DP-47 and DPL3) were selected to be highly compatible with the bacterial expression, and phage system employed, thus ensuring a high degree of functional protein display.
[0005] Another important aspect in the construction of the library was a demand on the framework to be able to hold specificities, with high affinities, against a large variety of different types of antigens. As the system allows variability to be introduced into any number of the CDR positions, the achievable variability is huge, far beyond what can be obtained by previously established combinatorial technologies. Finally, the modular design, i.e. the fact that variability is introduced into a common framework structure, makes subsequent modifications and studies of selected clones simple and efficient.
[0006] Using this technology, tentatively called CDR-implantation, a large phage display antibody library based on the single chain Fv (scFv) format has been created. The library has been used to select a panel of high affinity antibodies against a number of ligand types, including proteins (of human and non-human origin), peptides, carbohydrates and low-molecular weight haptens. Thus, from a functional point of view, it is clear that a single, selected, master framework can hold antibody specificities with high affinities against quite different types of antigens, suggesting that the topology of the surfaces may differ greatly between antibodies.
[0007] However, there remains a general need in the art to increase the diversity of antibody libraries.
SUMMARY OF THE INVENTION
[0008] According to the present invention, nucleic acid encoding a CDR that is normally contained in a framework (the “original framework”), which differs from a selected master framework, is amplified from an immunoglobulin gene and is inserted into nucleic acid encoding the selected master framework.
[0009] Amplification may be accomplished, as with conventional CDR implantation as described above, by PCR using primers based on the framework regions flanking the CDRs. However, in the present invention, the original framework and the master framework differ. In contrast with the previously described CDR implantation methods, therefore, nucleic acid encoding the CDRs is not amplified using primers based exclusively on the master framework Rather, primers are used which differ from the sequence encoding the master framework The primers may be based specifically on a particular other framework, e.g. that of a different germline gene or consensus sequence of a germline gene family, or may be degenerate, e.g. to amplify CDRs from a range of germline families.
[0010] Accordingly, in a first aspect, the present invention provides a method for producing a polynucleotide sequence encoding an antibody variable domain, the variable domain comprising complementarity-determining regions (CDRs) located within a selected framework (the “master framework”), the method comprising the steps of:
a) providing at least one nucleic acid molecule encoding one or more CDRs and associated framework regions (the ‘original framework’); b) amplifying at least one CDR-encoding portion of the nucleic acid molecule(s) of step (a) using one or more pairs of oligonucleotides as amplification primers and; c) assembling a polynucleotide sequence encoding an antibody variable domain by combining the amplified CDR-encoding nucleotide sequences produced in step (b) with nucleotide sequences encoding said master framework,
wherein the oligonucleotide primers of step (b) comprise nucleotide sequences which differ from the corresponding nucleotide sequences encoding said master framework.
[0014] A second aspect of the invention provides a method for producing a library of polynucleotide sequences each encoding an antibody variable domain comprising complementarity-determining regions (CDRs) located within a common selected framework (the ‘master framework’), the method comprising the steps of:
a) providing a population of nucleic acid molecules encoding one or more complementarity-determining regions (CDRs) and associated framework regions (the ‘original framework’); b) amplifying at least one CDR-encoding portion of the nucleic acid molecules of step (a) using one or more pairs of oligonucleotides as amplification primers and; c) assembling a polynucleotide sequence encoding an antibody variable domain by combining the amplified CDR-encoding nucleotide sequences produced in step (b) with nucleotide sequences encoding said master framework,
wherein the oligonucleotide primers of step (b) comprise nucleotide sequences which differ from the corresponding nucleotide sequences encoding said master framework.
[0018] By “associated framework regions”, as used in relation to the nucleic acid molecules provided in step (a), we mean the amino acid residues of the framework region immediately flanking the CDR. For example, the nucleic acid molecule(s) of step (a) may encode a CDR together with up to 5, 10, 15 or more amino acid residues of the framework flanking either side of the CDR. Thus, the nucleic acid molecule(s) of step (a) may encode an antibody variable region or even an entire antibody.
[0019] By “differ from”, in the context of the nucleotide sequences of the oligonucleotide primers of step (b), we mean that the regions of the oligonucleotide primers of step (b) which encode framework residues (i.e. those regions of the oligonucleotide primers which arc complementary to regions of the nucleic acid molecules provided in step (a) which encode framework residues) do not share 100% sequence identity with the corresponding regions of the nucleic acid molecules encoding the master framework.
[0020] In a preferred embodiment of the first and second aspects of the invention, the method comprises the steps of:
i) providing at least one pair of oligonucleotides; ii) using each said pair of oligonucleotides as amplification primers to amplify nucleotide sequences encoding different CDRs, and; iii) assembling polynucleotide sequences encoding antibody variable domains by incorporating nucleotide sequences derived from step ii) above with nucleotide sequences encoding framework sequences (FRs) of a selected type,
wherein the oligonucleotides of step (i) have sequences which differ from corresponding sequences encoding said master framework.
[0024] For the avoidance of doubt, the “framework” of a variable region, as used herein, is typically made up of four individual framework regions, which flank the three CDRs of the variable region:
[---FR1---][CDR1][---FR2---][CDR2][---FR3---][CDR3][---FR4---]
[0026] The “framework regions (FRs) of a selected type” together provide a “master framework”.
[0027] It will be appreciated by persons skilled in the art that the methods of the present invention may be used to produce a polynucleotide sequence encoding a variable domain of different types of antibody. For example, the variable domain may be an IgG, IgM, IgA, IgD or IgE variable domain.
[0028] Preferably, the polynucleotide sequence assembled in step (c) encodes an IgG variable domain. Advantageously, the polynucleotidc sequence(s) assembled in step (c) encodes an IgG heavy chain or light chain. Conveniently, the polynucleotide sequence(s) assembled in step (c) encodes a non-naturally occurring antibody variable domain.
[0029] Advantageously, the polynucleotide sequence(s) assembled in step (c) encodes an antibody variable domain comprising at least one CDR having a canonical structure which is atypical of antibody variable domains comprising the master framework By ‘atypical’ we mean that the CDR has a canonical structure which is found in less than 10% of naturally-occurring antibody variable domains comprising the selected master framework. Preferably, the CDR has a canonical structure which is found in less than 5%, 2% or 1% of naturally-occurring antibody variable domains comprising the selected master framework. Most preferably, the CDR has a canonical structure which is not found in any naturally-occurring antibody variable domains comprising the selected master framework.
[0030] In a preferred embodiment of the methods of the invention, at least one of the polynucleotide sequence(s) assembled in step (c) encode an antibody variable domain comprising at least one CDR derived a different germline gene family to that of the master framework. For example, the polynucleotide sequence(s) assembled in step (c) may encode an antibody variable domain comprising one or more CDRs derived from a light chain in heavy chain framework, or vice versa.
[0031] Advantageously, step (a) comprises providing a population of nucleic acid molecules each encoding an antibody variable domain. Conveniently, the nucleic acid molecules each encode an antibody variable domain from the same germline gene family. Thus, selectivity for the CDRs to be incorporated into the master framework may be achieved, at least in part, by providing a chosen population of nucleic acid molecules in step (a).
[0032] Alternatively, or in addition, selectivity for the CDRs to be incorporated into the master framework may be achieved by using oligonucleotide primer pairs in step (b) which selectively hybridise to a target sub-population of nucleic acid molecules provided in step (a). By ‘selectively hybridise’ we mean that the oligonucleotide primer pairs hybridise selectively to a target sub-population of nucleic acid molecules under conditions of high stringency. Oligonucleotide hybridisation conditions are described in Molecular Cloning: A Laboratory Manual (third edition), Sambrook and Russell (eds.), Cold Spring Harbor Laboratory Press.
[0033] It will be appreciated by persons skilled in the art that the ability of the primers to selectively hybridise with target nucleic acid molecules is dependent, to a large extent, on the degree of sequence complementarity between the primers and the target sequences.
[0034] Preferably, the oligonucleotide primer pairs in step (b) selectively hybridise to a target sub-population of nucleic acid molecules provided in step (a) each encoding an antibody variable domain from the same germline gene family.
[0035] Thus, by providing a chosen population of nucleic acid molecules in step (a) and/or by using oligonucleotide primer pairs in step (b) selectively hybridise to a target sub-population of nucleic acid molecules provided in step (a), it is possible to select the CDRs to be incorporated into the master framework.
[0036] In a preferred embodiment, the CDRs to be incorporated into the master framework are derived from nucleic acid molecules encoding an antibody variable domain lion, the same germline gene family, such as the V H 3 family. Conveniently, the CDRs to be incorporated into the master framework are derived from nucleic acid molecules encoding an antibody variable domain from the same germline gene, such as DP-29 and DP-73.
[0037] Advantageously, the master framework is derived from a germline gene selected from the group consisting of DP-47 and DPL-3.
[0038] In a preferred embodiment of the methods of the invention, step (c) comprises the use of overlap extension PCR (see Sambrook & Russell, supra). In this case, it is necessary to isolate single stranded nucleic acid molecules from the amplified CDR-encoding nucleic acid molecules produced in step (b). This may be achieved by using oligonucleotide primer pairs in which one of the primers is biotinylated, thereby enabling the nucleic acid stand produced by extension of the biotinylated primer to be isolated on the basis of its affinity for streptavidin. The use of biotinylated primers and overlap extension PCR is described in Jirholt et al, 1998, supra.
[0039] As a consequence of the differences in the nucleotide sequence between the regions of the amplification primers which encode framework residues and the nucleic acid sequences encoding the corresponding regions of the master framework, the amplified CDRs cannot always be incorporated directly into the master framework by overlap extension PCR since the nucleotides encoding the amplified CDRs may fail adequately to anneal with the nucleic acid encoding the master framework This is particularly the case when (as in Example 1B) there are significant mismatches at the ends of the amplification primers (notably at the end nearer the CDR). As a result, it may be necessary to alter the regions of the amplified nucleotide sequences which encode the framework regions flanking the CDRs to make them more similar in sequence to the regions of the nucleic acid molecules encoding the corresponding regions of the master framework.
[0040] Thus, in a preferred embodiment of the methods of the invention, the methods comprise a further step, performed after step (b) and prior to step (c), of modifying the nucleotide sequence of the amplified CDR-encoding molecules of step (b) such that the portions of said amplified molecules which encode framework regions share greater sequence identity with the corresponding portions of the master framework. Preferably the nucleotide sequences are modified such that the portions of said amplified molecules which encode framework regions share 100% sequence identity with the corresponding portions of the master framework.
[0041] For example, one way of accomplishing this is to initially amplify the CDR and adjacent portions of the flanking framework regions using PCR primers which are identical or very similar to the original framework of the CDR. Then, in successive rounds of PCR amplification, one can modify the regions of the amplified nucleic acid sequences which encode framework regions using primers containing mismatches relative to the original framework, those mismatches providing the residues present at corresponding positions in the master framework. Eventually, the framework regions become sufficiently similar, or identical, to the master framework to be incorporated therein by overlap extension PCR.
[0042] Alternatively, a single round of PCR amplification using primers that represent a chimaera of the original and master frameworks may suffice to amplify CDRs which can be used in the overlap extension PCR process, in which case the additional step is not required.
[0043] In the first round of PCR (Step ‘b’), therefore, irrespective of whether said additional steps are to be performed, it may be preferable to include mismatches in the primers relative to the original framework, in order to include as many bases as possible that are common to the selected master framework. The number of mismatches that can be included depends on a set of factors including the number of bases that differ between the frameworks, the length of the primers and the risk of annealing to sequences other than those intended.
[0044] It may be possible for CDRs amplified by primers which are identical to the original framework to be incorporated directly into the master framework (i.e. the products of step ‘b’), by overlap extension PCR. Alternatively, inclusion of additional PCR steps (as described above) may be necessary to make the framework sequences associated with the amplified CDR-encoding more similar to the corresponding sequences in the master framework.
[0045] In a preferred embodiment of the first aspect of the invention, the method comprising a further step of inserting the polynucleotide sequence(s) assembled in step (c) into an expression vector. Advantageously, the expression vector is a secretion vector.
[0046] Thus, polynucleotide sequences produced by the methods of the invention may be used in accordance with known techniques, appropriately modified in view of the teachings contained herein, to construct an expression vector, which is then used to transfonn an appropriate host cell for the expression and production of antibody variable domains. Such techniques include those disclosed in U.S. Pat. No. 4,440,859 issued 3 Apr. 1984 to Rutter et al, U.S. Pat. No. 4,530,901 issued 23 Jul. 1985 to Weissman, U.S. Pat. No. 4,582,800 issued 15 Apr. 1986 to Crowl, U.S. Pat. No. 4,677,063 issued 30 Jun. 1987 to Mark et al, U.S. Pat. No. 4,678,751 issued 7 Jul. 1987 to Goeddel, U.S. Pat. No. 4,704,362 issued 3 Nov. 1987 to Itakura et al, U.S. Pat. No. 4,710,463 issued 1 Dec. 1987 to Murray, U.S. Pat. No. 4,757,006 issued 12 Jul. 1988 to Toole, Jr. et al, U.S. Pat. No. 4,766,075 issued 23 Aug. 1988 to Goeddel et al and U.S. Pat. No. 4,810,648 issued 7 Mar. 1989 to Stalker, all of which are incorporated herein by reference.
[0047] The polynucleotide sequences produced by the methods of the invention may be joined to a wide variety of other DNA sequences for introduction into an appropriate host. The companion DNA will depend upon the nature of the host, the manner of the introduction of the DNA into the host, and whether episomal maintenance or integration is desired.
[0048] Generally, the polynucleotide sequence is inserted into an expression vector, such as a plasmid, in proper orientation and correct reading frame for expression. If necessary, the polynucleotide sequence may be linked to the appropriate transcriptional and translational regulatory control nucleotide sequences recognised by the desired host, although such controls are generally available in the expression vector. Thus, the polynucleotide sequence insert may be operatively linked to an appropriate promoter. Bacterial promoters include the E. coli lacI and lacZ promoters, the T3 and 17 promoters, the gpt promoter, the phage λ PR and PL promoters, the phoA promoter and the trp promoter. Eukaryotic promoters include the CMV immediate early promoter, the HSV thymidine kinase promoter, the early and late SV40 promoters and the promoters of retroviral LTRs. Other suitable promoters will be known to the skilled artisan. The expression constructs will desirably also contain sites for transcription initiation and termination, and in the transcribed region, a ribosome binding site for translation (Hastings et al, International Patent No. WO 98/16643, published 23 Apr. 1998).
[0049] The vector is then introduced into the host through standard techniques. Generally, not all of the hosts will be transformed by the vector and it will therefore be necessary to select for transformed host cells. One selection technique involves incorporating into the expression vector a DNA sequence marker, with any necessary control elements, that codes for a selectable trait in the transformed cell. These markers include dihydrofolate reductase, G418 or neomycin resistance for eukaryotic cell culture, and tetracyclin, kanamycin or ampicillin resistance genes for culturing in E. coli and other bacteria. Alternatively, the gene for such selectable trait can be on another vector, which is used to co-transform the desired host cell.
[0050] Host cells that have been transformed by the expression vector are then cultured for a sufficient time and under appropriate conditions known to those skilled in the art in view of the teachings disclosed herein to permit the expression of the encoded antibody variable domain, which can then be recovered.
[0051] The antibody variable domain can be recovered and purified from recombinant cell cultures by well-known methods including ammonium sulphate or ethanol precipitation, acid extraction, anion or cation exchange chromatography, phosphocellulose chromatography, hydrophobic interaction chromatography, affinity chromatography, hydroxylapatite chromatography and lectin chromatography. Most preferably, high performance liquid chromatography (“HPLC”) is employed for purification.
[0052] Many expression systems are known, including systems employing: bacteria (e.g. E. coli and Bacillus subtilis ) transformed with, for example, recombinant bacteriophage, plasmid or cosmid DNA expression vectors; yeasts (e.g. Saccaromyces cerevisiae ) transformed with, for example, yeast expression vectors; insect cell systems transformed with, for example, viral expression vectors (e.g. baculovirus); plant cell systems transfected with, for example viral or bacterial expression vectors; animal cell systems transfected with, for example, adenovirus expression vectors.
[0053] The vectors may include a prokaryotic replicon, such as the Col El ori, for propagation in a prokaryote, even if the vector is to be used for expression in other, non-prokaryotic cell types. The vectors may also include an appropriate promoter such as a prokaryotic promoter capable of directing the expression (transcription and translation) of the genes in a bacterial host cell, such as E. coli, transformed therewith.
[0054] A promoter is an expression control element formed by a DNA sequence that permits binding of RNA polymerise and transcription to occur. Promoter sequences compatible with exemplary bacterial hosts are typically provided in plasmid vectors containing convenient restriction sites for insertion of a DNA segment of the present invention.
[0055] Typical prokaryotic vector plasmids are: pUC18, pUC19, pBR322 and pBR329 available from Biorad Laboratories (Richmond, Calif., USA); pTrc99A, pKK223-3, pKK233-3, pDR540 and pRIT5 available from Pharmacia (Piscataway, N.J., USA); pBS vectors, Phagescript vectors, Bluescript vectors, pNH8A, pNH16A, pNH18A, pNH46A available from Stratagene Cloning Systems (La Jolla, Calif. 92037, USA).
[0056] A typical mammalian cell vector plasmid is pSVL available from Pharmacia (Piscataway, N.J., USA). This vector uses the SV40 late promoter to drive expression of cloned genes, the highest level of expression being found in T antigen-producing cells, such as COS-1 cells. An example of an inducible mammalian expression vector is pMSG, also available from Pharmacia (Piscataway, N.J., USA). This vector uses the glucocorticoid-inducible promoter of the mouse mammary tumour virus long terminal repeat to drive expression of the cloned gene.
[0057] Useful yeast plasmid vectors are pRS403-406 and pRS413-416 and are generally available from Stratagene Cloning Systems (La Jolla, Calif. 92037, USA). Plasmids pRS403, pRS404, pRS405 and pRS406 are Yeast Integrating plasmids (YIps) and incorporate the yeast selectable markers HIS3, TRP1, LEU2 and URA3. Plasmids pRS413-416 are Yeast Centromere plasmids (YCps).
[0058] Methods well known to those skilled in the art can be used to construct expression vectors containing the coding sequence and, for example appropriate transcriptional or translational controls. One such method involves ligation via homopolymer tails. Homopolymer polydA (or polydC) tails are added to exposed 3′ OH groups on the DNA fragment to be cloned by terminal deoxynucleotidyl transferases. The fragment is then capable of annealing to the polydT (or polydG) tails added to the ends of a linearised plasmid vector. Gaps left following annealing can be filled by DNA polymerase and the free ends joined by DNA ligase.
[0059] Another method involves ligation via cohesive ends. Compatible cohesive ends can be generated on the DNA fragment and vector by the action of suitable restriction enzymes. These ends will rapidly anneal through complementary base pairing and remaining nicks can be closed by the action of DNA ligase.
[0060] A further method uses synthetic molecules called linkers and adaptors. DNA fragments with blunt ends are generated by bacteriophage T4 DNA polymerase or E. coli DNA polymerase I which remove protruding 3′ termini and fill in recessed 3′ ends. Synthetic linkers, pieces of blunt-ended double-stranded DNA which contain recognition sequences for defined restriction enzymes, can be ligated to blunt-ended DNA fragments by T4 DNA ligase. They are subsequently digested with appropriate restriction enzymes to create cohesive ends and ligated to an expression vector with compatible termini. Adaptors are also chemically synthesised DNA fragments which contain one blunt end used for ligation but which also possess one preformed cohesive end.
[0061] Synthetic linkers containing a variety of restriction endonuclease sites are commercially available from a number of sources including International Bioteclmologies the, New Haven, Conn., USA.
[0062] A desirable way to modify the DNA encoding the polypeptide of the invention is to use the polymerase chain reaction as disclosed by Saiki et at (1988) Science 239, 487-491. In this method the DNA to be enzymatically amplified is flanked by two specific oligonucleotide primers which themselves become incorporated into the amplified DNA. The said specific primers may contain restriction endonuclease recognition sites which can be used for cloning into expression vectors using methods known in the art.
[0063] Thus, a third aspect of the present invention provides a polynucleotide sequence producible and/or produced by a method of the first or second aspects of the invention.
[0064] A fourth aspect of the invention provides a polypeptide encoded by a polynucleotide sequence according to the third aspect of the present invention, for example an antibody or fragment thereof (e.g. single chain ScFv antibodies).
[0065] The invention further provides a vector incorporating a polynucleotide sequence according to the second aspect of the present invention, and host cells transformed by such vectors. Exemplary host cells include mammalian cells such as Chinese hamster ovary cells.
[0066] In a preferred embodiment, the expression vector is a phage display vector.
[0067] The display of proteins and polypeptides on the surface of bacteriophage (phage), fused to one of the phage coat proteins, provides a powerful tool for the selection of specific ligands. This ‘phage display’ technique was originally used by Smith in 1985 ( Science 228, 1315-7) to create large libraries of antibodies for the purpose of selecting those with high affinity for a particular antigen. More recently, the method has been employed to present peptides, domains of proteins and intact proteins at the surface of phages in order to identify ligands having desired properties.
[0068] The principles behind phage display technology are as follows:
(i) Nucleic acid encoding the protein or polypeptide for display is cloned into a phage; (ii) The cloned nucleic acid is expressed fused to the coat-anchoring part of one of the phage coat proteins (typically the p3 or p8 coat proteins in the case of filamentous phage), such that the foreign protein or polypeptide is displayed on the surface of the phage; (iii) The phage displaying the protein or polypeptide with the desired properties is then selected (e.g. by affinity chromatography) thereby providing a genotype (linked to a phenotype) that can be sequenced, multiplied and transferred to other expression systems.
[0072] Alternatively, the foreign protein or polypeptidc may be expressed using a phagemid vector (i.e. a vector comprising origins of replication derived from a phage and a plasmid) that can be packaged as a single stranded nucleic acid in a bacteriophage coat. When phagemid vectors are employed, a “helper phage” is used to supply the functions of replication and packaging of the phagemid nucleic acid. The resulting phage will express both the wild type coat protein (encoded by the helper phage) and the modified coat protein (encoded by the phagemid), whereas only the modified coat protein is expressed when a phage vector is used.
[0073] Methods of selecting phage expressing a protein or peptide with a desired specificity are known in the art. For example, a widely used method is “panning”, in which phage stocks displaying ligands are exposed to solid phase coupled target molecules, e.g. using affinity chromatography.
[0074] Alternative methods of selecting phage of interest include SAP (Selection and Amplification of Phages; as described in WO 95/16027) and SIP (Selectively-Infective Phage; EP 614989A, WO 99/07842), which employ selection based on the amplification of phages in which the displayed ligand specifically binds to a ligand binder. In one embodiment of the SAP method, this is achieved by using non-infectious phage and connecting the ligand binder of interest to the N-terminal part of p3. Thus, if the ligand binder specifically binds to the displayed ligand, the otherwise non-infective ligand-expressing phage is provided with the parts of p3 needed for infection. Since this interaction is reversible, selection can then be based on kinetic parameters (see Duenas et al., 1996, Mol. Immunol. 33, 279-285).
[0075] The use of phage display to isolate ligands that bind biologically relevant molecules has been reviewed in Felici et al. (1995) Biotechnol. Annual Rev. 1, 149-183, Katz (1997) Annual Rev. Biophys. Biomol. Struct. 26, 27-45 and Hoogenboom et al. (1998) Immunotechnology 4(1), 1-20. Several randomised combinatorial peptide libraries have been constructed to select for polypeptides that bind different targets, e.g. cell surface receptors or DNA (reviewed by Kay, 1995, Perspect. Drug Discovery Des. 2, 251-268; Kay and Paul, 1996, Mol. Divers. 1, 139-140). Proteins and multimeric proteins have been successfully phage-displayed as functional molecules (see EP 0349578A, EP 0527839A, EP 0589877A; Chiswell and McCafferty, 1992, Trends Biotechnol. 10, 80-84). In addition, functional antibody fragments (e.g. Fab, single chain Fv [scFv]) have been expressed (McCafferty et al, 1990, Nature 348, 552-554; Barbas et al., 1991, Proc. Natl. Acad. Sci. USA 88, 7978-7982; Clackson et al., 1991, Nature 352, 624-628), and some of the shortcomings of human monoclonal antibody technology have been superseded since human high affinity antibody fragments have been isolated (Marks et al., 1991, J. Mol Bio. 222, 581-597; Hoogenboom and Winter, 1992, J. Mol. Biol. 227, 381-388). Further information on the principles and practice of phage display is provided in Phage display of peptides and proteins: a laboratory manual Ed Kay, Winter and McCafferty (1996) Academic Press, Inc ISBN 0-12-402380-0, the disclosure of which is incorporated herein by reference.
[0076] Thus, in a preferred embodiment of the first and second aspects of the invention, the method further comprises the step of expressing the polynucleotide sequence(s) assembled in step (c) and screening the resultant polypeptide(s), comprising an antibody variable domain, for desired properties. Preferably, the desired properties are readily selectable by known techniques. For example, antibodies may be screened for desired affinity using affinity chromatographic methods.
[0077] A further aspect of the invention provides a polynucleotide library producible by a method according to the second aspect of the invention, i.e. comprising polynucleotides producible by a method according to the first aspect of the invention. Such a library will comprise polynucleotides encoding a population of antibody variable domains, each of which shares a common framework (the ‘master framework’).
[0078] Preferably, the polynucleotide library is an expression vector library. Conveniently, the polynucleotide library is a phage display library.
DETAILED DESCRIPTION OF THE INVENTION
[0079] The present invention represents a development of the technology presented in W098/32845, Söderlind et al. (1999) Immunotechnology 4, 279-285, and Jirholt et al. (1998) Gene 215, 471-476, all of which are incorporated herein in their entirety, particularly for the purpose of describing generally the methods and conditions used for amplifying CDRs from a cDNA library containing antibody-encoding sequences, and methods, materials and conditions for reassembling the CDRs thus amplified into the master framework by overlap extension PCR.
[0080] The method may further comprise the step of expressing the resulting antibody encoded by the assembled nucleotide sequence and screening for desired properties. Again, this is described in detail in the above-mentioned references.
[0081] The resulting expressed antibody can be screened for desired characteristics. For example it may be desirable to alter its ability to specifically bind to an antigen or to improve its binding properties in comparison to the parent antibody. Once more, this is described in detail in the above-mentioned references.
[0082] Preferably the oligonucleotides used for amplification primers have at least two nucleic acid residues different from a corresponding portion of the nucleic acid sequence encoding the master framework. More preferably there are at least 3, 4, 5, 6, 7, 8, 10 or 12 different nucleic acid residues. In an alternative definition, the amplification primers preferably have no more than about 95% sequence identity with a corresponding portion of the nucleic acid sequence encoding the master framework, more preferably no more than about 90%, 85%, 80%, 70% or 60% sequence identity.
[0083] In conventional CDR implantation, the amplification primers may include a small number of nucleotides encoding one or more amino acid residues of the adjoining end of the CDR (e.g. three nucleotides, encoding one CDR residue). This applies also to the present invention, and in such cases, the nucleotides of the CDR may be discounted when determining the number of nucleotide differences between the primer and the master framework.
[0084] Bearing in mind the teaching herein, and given in the cited references on the basic CDR-implantation technique, the skilled person will be able to design primers for amplifying the CDRs and, if necessary or desired, for modifying the amplification products to make their framework regions more similar to the selected master framework.
[0085] Where a particular germline gene is to be targeted, highly specific primers maybe desired, for example based closely on the sequence encoding the parts of the framework regions of that gene which flank the CDR or CDRs to be amplified. The sequences of different germline genes are available from the VBASE sequence directory (URL: http://www.mrc-cpe.cam.ac.uk/imt-doc/public/INTRO.html) or from the DNAplot directory (URL: http://www.genetik.uni-koeln.de:80/dnaplot/vsearch human.html).
[0086] Similarly, the primers can be designed to amplify CDRs from a particular germline gene family, by designing primers based on the consensus sequence of genes of that family. For example, a consensus sequence can be defined as the sequence of bases found at >90% of loci of a particular germline family. Such sequences may include degenerate sites, indicating that different individual sequences have different nucleotides at that site. There may nevertheless be some common feature of the nucleotide residues which appear at such a degenerate site; such sites are designated R (purine; bases G and A), Y (pyrimidine; C, T), M (amino; A, C), K (keto; T, G), S (strong; C, G), W (weak, A, T), B (not A), D (not C), H (not G) or V (not T). A site where no common feature is evident is designated N (any).
[0087] Primers based on consensus sequences including such designations may be degenerate, i.e. a population of primers is made to include all possible combinations consistent with the consensus sequence, or where appropriate artificial bases which mimic particular sets of bases may be included within a homogeneous population of primers.
[0088] Information ascribing germline genes to germline gene families (such as the variable heavy germline gene families V H 1, V H 2, V H 3, V H 4, V H S, V H 6 and V H 7) is available from the VBASE directory referred to above.
[0089] Similarly, it is possible also to design the primers to amplify CDRs from a plurality of germline gene families, using a consensus sequence of germline genes from said plurality of families. However, it will generally be preferred to target a particular germline gene or family.
[0090] With this in mind, the skilled person will be able to design appropriate primers depending on the specificity required. Preferably at least one primer of the or each pair used to initially amplify the CDRs is at least 15 nucleotides in length, more preferably at least 18, still more preferably at least 21 or 24, optionally at least 30, 36 or 42. Preferably, however, the primer is no more than 42 nucleotides in length, more preferably no more than 36 or 30, more preferably no more than 27.
[0091] Preferably the method will be used to implant CDRs at all three positions in the variable domain, since this leads to maximum variability, and ultimately more useful libraries. However, the method is not limited to this, and if desired (for example to optimise a previously obtained antibody), the method may be used to implant only one or two CDRs. In such cases, nucleic acid encoding the invariant CDR(s) will be included in the overlap extension PCR step, in addition to the newly amplified CDRs and the nucleic acid encoding the selected master framework.
[0092] The present invention is not to be construed as limited to implanting CDRs from immunoglobulin genes of the same general type as the master framework (e.g. implanting V H CDRs into V H master framework), although this is a preferred embodiment of the invention. Rather, the invention in its broader aspects includes the implantation of CDR-encoding nucleic acid from any type of inununoglobulin gene which has a variable region as defined above into a master framework which is independently of any such type of immunoglobulin superfamily gene. For example, Vλ CDRs may be inserted into a V H master framework and vice versa. Moreover, any members of the immunoglobulin superfamily having analogous structures to CDRs and FRs may provide the CDRs and/or master FRs of the invention, the above description being applicable mutatis mutandis.
[0093] The term “antibody” is used herein in its broadest sense, to include also antibody fragments having a variable domain which includes CDRs flanked by framework regions. Examples of antibody fragments having such variable domains are the Fab fragment consisting of the V L , V H , C L and C H 1 domains; the Fd fragment consisting of the V H , and C H 1 domains; the Fv fragment consisting of the V L and V H domains of a single arm of an antibody; the dAb fragment which consists of a V H domain; and the F(ab′)2 fragment, a bivalent fragment including two Fab fragments linked by a disulphide bridge at the hinge region. Single chain Fv fragments are also included.
[0094] Any desired master framework regions (or “framework regions (FRs) of a selected type”) may be utilised in the present invention. In particular, they may be selected to be highly compatible with the bacterial expression system, and phage system, to be employed, thus ensuring a high degree of functional protein display. Favoured examples are framework regions from the DP-47 and DPL-3 germline genes (of the V H 3 and Vλ germline gene families, respectively).
[0095] It is now generally agreed that the CDR-loops, which build up the surfaces of antibody combining sites, can be grouped into a limited number of so-called canonical structures, depending on their conformation after folding. The pioneering work in this area was performed by Cothia and Lesk (1987) who classified CDR 1 and 2 in the heavy chain and CDR 1-3 in the light chain into a few basic structures.
[0096] The concept of canonical structures is the result of extensive analyses of empirically determined and analysed antibody structures. The determinants for the canonical conformations are the lengths of the loops, key residues in the loops and key residues in the adjacent framework sequences (Chothia et al. 1992; Tomlinson et al. 1995; Al-Lazikani et al. 1997). For example, the human Vκ sequences can be grouped in 6 canonical structures for the CDRL1 loop, 1 canonical structure for the CDRL2 loop and 5 canonical structures for the CDRL3 loop. Similarly, the human V H sequences can be grouped in 3 canonical structures for the CDRH1 loop and 4 canonical structures for the CDRH2 loop.
[0097] The CDRH3 loop has not yet been classified in distinct canonical classes, most probably due to its inherited length variation which leads to unique properties regarding flexibility. However, recently it was demonstrated that this CDR also is built from structure elements forming a basic torso near, and to some extent including, the framework region, and an apical head region that sometimes includes an additional shoulder (Morea et al. 1998).
[0098] It is conceivable that nature has developed different types of canonical structures to deal with the multitude of antigenic structures the immune systems may encounter. Nature also presents these structures in the context of different framework structures. Thus, a particular CDR-loop is found in combination with a certain framework (VBASE). There also seems to be a bias to which canonical structures arc used in order to create suitable surfaces, complementary to different types of antigens. In particular, loops with canonical structures building up a flat surface seem to yield surfaces that bind well to large protein antigens. These loops have a propensity to be rather short whereas longer loops are preferentially found in antibodies specific for smaller molecules e.g. haptens (Lara-Ochoa et al. 1996). Not all loops seem to be equally important in creating variability in the surfaces. Of course H3 is of major importance in this respect but also H2 and L1 determine the surfaces to a great extent (Vargas-Madrazo et al. 1995).
[0099] Using the CDR-implantation technology it has unexpectedly been found that some of the selected antibodies comprised CDRs with canonical structures that are not normally found in the used framework. These antibodies are functional since they bind their antigen with high affinity (Example 1). Thus, using a single framework it is possible to create functional variability in antibody combining sites that is based on canonical loops that are atypical in a certain framework context. A library based on such a concept would have advantages over more conventional libraries since it can harbour antibodies with a wide variety of topologies and at the same time be highly efficient in the selected host system (e.g. E. coli ).
[0100] Furthermore, the binding characteristics of antibodies could be improved using shuffling of selected CDRs in order to recombine the most optimal CDRs into a single antibody molecule. As will be appreciated, CDR-implantation technology permits shuffling of 1 to 6 CDRs at the same time and has been used on the basis of the library presented herein in the Examples to improve affinities of selected antibodies more than 30 times in a single step.
[0101] The present invention may therefore lead to novel combinations of classes of canonical structure, for example by combining canonical structures of classes that are not normally found in genes of the same germline family. For example, by incorporating CDRH2 CDRs into the CDRL2 position of a Vκ chain, variability from 4 classes of canonical structure can be accessed in this position, whereas in the natural Vκ antibody, there is only one class of canonical structure used in the CDRL2 position.
[0102] Preferably, the amplification primers are designed to amplify CDRs of a greater number of classes of canonical structure than the number of classes of canonical structure found in the germline gene family to which the master framework belongs, or CDRs of different classes of canonical structure from those found in the gcmnlinc gene family to which the framework belongs. Predictions of the canonical structure adopted by a particular CDR may be determined using an online tool available at URL: http://www.biochem.ucl.ac.uk/˜martin/abs/chothia.html.
[0103] The master framework need not be a naturally occurring one, but may for example have been optimised, e.g. for the expression or phage system to be used, or to reduce antigenicity in vivo.
[0104] The CDRs, having been amplified, may be subject to mutagenesis, e.g. using error-prone PCR, before being incorporated into the master framework (e.g. as described in WO98/32845), though this is not generally preferred since naturally occurring CDRs are less likely than artificial ones to be antigenic.
[0105] “Percent (%) nucleic acid sequence identity” is defined as the percentage of nucleic acid residues in a candidate sequence that are identical with the nucleic acid residues in the sequence with which it is being compared, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part of the sequence identity. The percent identity values used herein were generated by the BLASTN module of WU-BLAST-2 (which was obtained from Altschul et al. (1996); URL: http://blast.wustl/edu/blast/README.html). WU-BLAST-2 uses several search parameters, most of which are set to the default values. The adjustable parameters are set with the following values: overlap span=1, overlap fraction=0.125. A percent nucleic acid sequence identity value is determined by the number of matching identical residues divided by the total number of residues of the “longer” sequence in the aligned region, multiplied by 100. The “longer” sequence is the one having the most actual residues in the aligned region (gaps introduced by WU-BLAST-2 to maximize the alignment score are ignored).
[0106] The following examples are provided for the better understanding of the invention, and make reference to the accompanying figures, in which:
[0107] FIG. 1 (parts A to D) shows the incorporation of a CDRH2 loop from germline gene DP-29 into a framework of DP-47.
[0108] FIG. 2 (parts A to E) shows the incorporation of a CDRH2 loop from germline gene DP-73 into a framework of DP-47.
EXAMPLES
Design of Primers and Assembly of Antibody Genes
[0109] Primers that are different from corresponding sequences in the DP-47 framework are used to amplify CDRs from different germline genes. In example 1A, the master framework and the framework of the gene from which the CDR is amplified (DP-29) are sufficiently similar that the thus-amplified sequence can be incorporated into a DP-47 framework without further modification. In example 1B, the frameworks are more dissimilar, and the thus-amplified sequence is further modified to make it more similar to the DP-47 framework before it is incorporated therein. This is achieved by use of primers that successively bring the framework regions that flank the CDRs into conformity with the selected framework in a designed and planned iterative process. In this way, it is possible to pick up CDR-loops that have canonical structures that are atypical of the selected DP-47 framework.
[0110] When, as here, it is desired to incorporate a specific CDR into the master framework, it can be advantageous to determine the homology (i.e. percentage identity) between the selected framework and the framework surrounding the atypical CDR to be incorporated into the selected framework. Of course, if one is using primers of a known sequence to “fish” for CDRs in a library, it is more important to determine the homology between the primers and the framework sequence.
[0111] The degree of homology determines the number of PCR amplification steps necessary to obtain the atypical CDR in the selected framework. This means that a lower degree of homology will result in several sequential PCR steps to convert the original FR flanking the atypical CDR into the sequence of the selected FR.
Example 1A
[0112] FIG. 1 shows the sequences and steps involved in the amplification of DP-29 CDRH2, and its incorporation into nucleic acid encoding framework of DP-47.
[0113] Part A shows nucleic acid sequences encoding portions of the framework regions flanking the DP-47 and DP-29 CDRH2 loops and the deduced amino acid equences. Nucleotide matches are denoted by the symbol I. As will be seen, here are some mismatches: 8 of 36 nucleotides and 7 of 27 nucleotides in the two flanking portions shown, respectively.
[0114] Part B shows amplification primers (“#1 primers”) identical to the nucleic acid encoding portions of the framework regions flanking the DP-29 CDRH2 loops, aligned with the double-stranded DP-29 coding sequence.
[0115] Part C shows the amplification product (“#1 product”) of the first PCR step (which was shown in Part B). Conditions for amplification are as for CDR amplification in WO98/32845. The #1 product is identical to the coding sequence of DP-29. Aligned with this are primers (“#2 primers”) for a second PCR step. These are identical to the nucleic acid encoding corresponding portions of the framework regions flanking the DP-47 CDRH2 loops. Consequently the same mismatches are apparent as in part A.
[0116] Part D shows the product (“#2 product”) of the second PCR step. This has the framework regions of DP-47 (the master framework) and the CDRH2 loop of DP-29.
[0117] Thus, there is sufficient sequence identity between the framework regions of DP-47 and DP-29 flanking the CDRH2 loop for the loop to be switched from one framework to the other in a single PCR step.
[0118] The DP-29 germlinc gene encodes a CDRH2 of canonical class 4 (VBASE), whereas the CDRH2 of DP-47 is of canonical class 3 (VBASE).
[0119] The second PCR step could be performed as an overlap extension PCR step, since the primer used is identical to the master framework sequence into which the CDR is intended to be incorporated, for example using the conditions (and other primers) set out in WO98/32845.
Example 1B
[0120] An iterative process of sequential PCR amplifications is used to insert a CDR into a DP-47 master framework from a germline gene (DP-73) which has significantly different sequences encoding the portions of the framework regions flanking the CDR. In this example the homology between the DP-47 V H framework, adjacent to CDRH2, and the DP-73 framework is too low to allow for direct amplification (e.g. in an overlap extension PCR step) using primers wholly identical to DP-47. Thus, several individual PCR steps are used, each step using a unique primer pair. The primers are successively modified to become more homologous to the DP-47 primer.
[0121] In this process it is important to carefully choose the proper distribution of the base modifications. FIG. 2 shows this process. The underlined sequence is where the greatest differences occur between DP-47 and DP-73. Bold letters denote residues in the primers which are identical to those in DP-47, the master framework.
[0122] Parts A and B are analogous to the same parts of FIG. 1 . Again, there are mismatches between the sequences encoding the portions of framework which flank the DP-47 and DP-73 CDRH2 loops, 13 mismatches out of 42 nucleotides and 9 mismatches out of 27 in the two flanking sequences, respectively.
[0123] In part C, instead of using primers identical to DP-47, primers which are chimaeras of DP-47 and DP-73 are used, to introduce changes into the framework regions of the amplified DP-73 fragment, to bring them partly into conformity with those of DP-47. So, rather than there being no mismatches between the primers and the DP-47 sequences (as in Example 1A), there are still some mismatches, though fewer than before, i.e. 2 in each flanking sequence.
[0124] Part D shows the amplification product (“#2 product”) of the second PCR step, aligned with primers (“#3 primers”) identical to corresponding portions of the DP-47 framework. As with example 1A, such primers could be used in overlap extension PCR. The third amplification step (analogously to the second in example 1A) leads to a fragment incorporating CDRH2 of DP-73 in a framework of DP-47.
[0125] In particular, in the second PCR step (which uses the #2 primers, shown in part C), the following base substitutions are made in the upper PCR primer relative to the #1 primer, used in the first PCR step (shown in part B): At position 35 (counted from the 5′ end of the primer) G is changed to C; at position 37 A is changed to G and at position 38 T is changed to C. This results in a higher degree of homology than if a primer homologous to DP-47 was to be used directly in the second PCR step.
[0126] The intermediate PCR product from the second PCR step therefore still contains uses that are homologous to the DP73 sequence (G36 and C39). These bases will hen not prime in the third PCR step, since the upper primer used in this step is 100% homologous to the DP47 sequence. However, bases 34, 37 and 38 of the amplification product (“#2 product”) of the second amplification step are now homologous to the DP-47 sequence and this homology will give an annealing of 6 of 8 bases at the 3′ end (underlined) of the upper primer in the third PCR step (shown in part D). This is to be compared to 3 out of 8 bases at the 3′ end between DP47 and DP73. Such an increase in homology greatly facilitates the successful production of a DNA sequence comprising the DP-73 CDRH2 in the DP-47 framework.
[0127] Using the principles of this method any CDR can be transferred to any given and selected framework resulting in composite antibody molecules that possess combinations of natural CDR-loops and hence possibly also canonical structures, that can not be found in nature. Thus, combination of atypical but natural CDR-loops gives a basis for generation of an enormous variability in the antibody combining site and the created variants may be captured in large libraries using e.g. phage (Marks et al. 1991), ribosome (Hanes and Pluckthun, 1997) or covalent (WO98/37186) display technologies.
REFERENCES
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The present invention relates to a method for in vivo molecular evolution of antibody function. According to the present invention, a nucleic acid encoding a CDR that is normally contained in a framework (the “original framework”), which differs from a selected master framework, is amplified from an immunoglobulin gene and is inserted into a nucleic acid encoding the selected master framework. The invention further provides an antibody library, such as a phage display library, and methods of making the same.
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The present invention is directed to a fuel vapor recovery canister and to an assembly comprising such canister, for capture and recovery of fuel vapors which otherwise would escape from a motor vehicle fuel tank into the atmosphere.
BACKGROUND OF THE INVENTION
Carbon canister storage systems are known for storing fuel vapors emitted from an automotive-type fuel tank or carburetor float bowl or other similar fuel reservoir to prevent emissions of fuel vapors into the atmosphere. These systems usually consist of a canister containing carbon or other medium which will releasably adsorb the fuel vapors. The canister would have an inlet from the fuel tank or other source of fuel vapors, the fuel vapors flowing typically under slight pressure into the canister to be adsorbed and stored by the filter medium therein. The canister also typically would have a fresh air inlet and a purge line connected to the engine intake manifold. During operation of the engine, vacuum in the intake manifold would draw air through the canister to the engine, thereby desorbing the filter medium of the fuel vapors.
Fuel vapor emission control canisters generally and their use in controlling emissions of fuel vapors from motor vehicles are well known to the skilled of the art. Such canisters, in addition to housing a bed of an adsorbent material, often provide other filtering means. Exemplary of such technology is that taught in U.S. Pat. No. 4,568,797 to Brand; U.S. Pat. No. 4,454,849 to Mizuno et al; and U.S. Pat. No. 4,326,489 to Heitert.
In U.S. Pat. No. 3,683,597 to Beveridge et al an activated charcoal canister assembly 16 is shown for controlling loss of fuel vapor from a vehicle fuel tank. The canister assembly comprises a molded body 16 having an upper end wall characterized by an annular outer portion 28 provided with flat ribs 32 which extend radially to a sealing lip 31. A cover member 40 is secured to a cylindrical inner wall 30. Chamber 45 within molded body 16 contains charcoal 46 retained by lower closure member 47 and screen 48. Wave spring 49 provides an upward bias against lower closure member 47. The lower closure member has a grid structure, including radial ribs 56. Additional canister configurations disclosed by Beveridge et al include compressed polyurethane pads to retain adsorbing material within the canister tightly packed. The Beveridge et al devices do not lend themselves as readily as is desirable to automatic assembly operations. In U.S. Pat. No. 3,728,846 to Nilsson a fuel vapor recovery system is shown comprising a filter connected by a vent line to the fuel tank. The filter is located in the engine compartment and the vent line is "lead through the upper portion of the vehicle body." The filter 6 comprises an open canister 19, the bottom of which is provided with a plurality of perforations 20 and serves as an air intake. Within the canister there is, at the bottom, an air filter element 21 and above this a filter portion 22 consisting of a filter element 23. The top and bottom of filter element 23 are bordered by a thin layer 24 of air pervious material, such as foamed plastic. Placed outside the layers 24 are filter element bottoms 25 that are perforated, have a certain rigidity and are intended to hold the filter portion 22 together. The filter element 23 is said to consist of active carbon grains. The canister 19 is sealed by a lid 26. A first hole 27 through the upper lid is connected to the vent line from the fuel tank. A second hole 28 is connected to the motor's air intake system. An apparently rigid and fixed central collar 29 extends inwardly from lid 26 to bear against the upper filter element bottom 25 to fix the position of the filter portion 22 within the canister. In U.S. Pat. No. RE 26, 196 to Hall a cylindrical evaporative emission canister for a motor vehicle has a filter 27 open to the atmosphere at one end through a screen 29. A vent line 13 from the opposite end of the canister is connected to a fuel tank 11. A duct 22 leads from the engine air cleaner 16 to an electrically driven, heat actuated air pump 23. Air pump 23 operates when the engine 10 is both off and hot. Discharge line 26 from the air pump 23 leads to the filter 27 containing suitable adsorbent material 28 such as charcoal. A conduit 30 from the filter 27 leads to a thermal cleaning device 31 which is connected by an air duct 32 to the carburetor 15. All vent lines (line 13 from fuel tank to filter, line 26/22 from air cleaner to filter, and line 32/30 from carburetor to filter) extend into the filter 27 and there are in fluid communication with each other. In U.S. Pat. No. 3,854,911 to Walker an arrangement is shown for controlling evaporation from a carburetor float bowl of an engine and from an associated pressurized fuel tank. Vapors are vented to a vapor absorbing canister 21. In U.S. Pat. No. 4,058,380 to King an evaporative emission control system having a bed of activated carbon is provided with one or more baffles to route the vapors therethrough to improve efficiency of emission control. In U.S. Pat. No. 4,203,401 to Kingsley et al an evaporative emission control canister has a cylindrical canister housing, a closed lower end wall, an upper end wall and a cylindrical inner wall depending from the upper end wall. An air-vapor permeable support means is positioned within the housing above the lower end wall in abutment against the lower free end of the cylindrical inner wall. This defines, with the lower end wall, an air chamber in fluid communication with the atmosphere. It also defines, within the canister, an outer canister chamber and an inner canister chamber. The inner canister chamber is connected by a fuel bowl vent valve to the float bowl of an engine to receive vapors from the float bowl when the engine is not in operation. The outer canister chamber is connected to receive vapors emitted from the fuel tank. Both the inner and outer chamber within the canister are connected to the vapor purge chamber of a vapor purge control valve, whereby fuel vapors can be purged from the canister assembly to the engine during engine operation. In U.S. Pat. No. 4,306,894 to Fukami et al a canister for a fuel evaporative emission control system of an engine contains adsorbent divided into at least two layers by a pair of spaced filter plates, so that fuel vapors can be defused into all parts of the adsorbent layers under the action of the filter plates and the hollow space between them. In U.S. Pat. No. 4,326,489 to Heitert a fuel evaporative loss control system comprise a canister 22 containing carbon and having a purge line leading to an engine intake manifold. A purge control valve meters the purged fuel vapors into the engine in an amount proportionate to the rate of air flow to the engine. The interior of the shell 30 of canister 22 is partitioned into two end chambers 40 and 42 by a pair of annular steel perforated screen plates 44 and 46, respectively. The space between the screens being filled with activated charcoal or other suitable vapor adsorbent 23. A spring 50 located between screen 44 and the cover 32 of the canister biases the upper screen against the adsorbent. In U.S. Pat. No. 4,454,849 to Mizuno et al a canister for a fuel vapor emission control comprises a fuel vapor guiding pipe 16 which extends into a bed of adsorbent material within the canister housing, and a deflector 17 within the adsorbent for deflecting the flow of fuel vapors and thereby dispersing them throughout the bed. Finally, in U.S. Pat. No. 4,658,797 to Brand a ventilation device for the fuel tank of a motor vehicle, includes a ventilation line 3 connecting the tank with the atmosphere through a fuel vapor filter 4. The filter 4 also is connected to the intake system 6 of the vehicle engine 1 by means of a filter exhaust line 5. A valve 7 in line 5 is closed when the engine is off to prevent the collection of fuel vapors in the intake system.
SUMMARY OF THE INVENTION
According to the present invention, a fuel vapor recovery assembly comprises:
adsorption means for releasably adsorbing fuel vapor from a fuel vapor-bearing fluid;
open-ended housing means for housing said adsorption means, said housing means comprising:
end closure means forming a fluid tight seal with an open end of the housing means and having a first fluid flow port means therethrough for communicating a flow of fuel vapor into and out of the housing means, and a second fluid flow port means remote from the first and in fluid communication with the atmosphere for communicating a fluid flow into and out of the housing means, wherein the first and second fluid flow port means are in communication with each other within the housing means through the aforesaid adsorbing means;
first barrier means within the housing means for separating the adsorption means from the first fluid flow port means and for allowing fluid communication between the first fluid flow port means and the adsorption means;
second barrier means within the housing means for separating the adsorption means from the second fluid flow port means and for allowing fluid communication between the second fluid flow port means and the adsorption means;
the housing means, first barrier means and second barrier means cooperating to contain the adsorption means;
biasing means comprising a coil spring positioned intermediate the end closure means and the first barrier means for biasing the barrier means against the adsorption means to place the adsorption means under compressive force; and
inwardly opening groove means at an inside surface of said housing means proximate said end closure means for receiving corresponding portions of a coil of said coil spring.
The invention also provides, according to another aspect thereof, a motor vehicle fuel system comprising a refillable fuel tank adapted to hold a quantity of volatile fuel for delivery by fuel sending means to an engine and a fuel vapor recovery assembly as described above in fluid communication with a vent of the fuel tank through which vapor of the volatile fuel can be vented from the fuel tank.
From the present disclosure those skilled in the art will appreciate the significance and advantages of the invention. It will be recognized, for example, that the fuel vapor recover assembly can be manufactured and assembled according to well known, commercially and economically feasible methods and processes, as further discussed below. The assembly can be manufactured in an infinite range of sizes. It can be manufactured in a single size and connected either in parallel or, more preferably, in series to provide adsorption capacity adapted to each particular application. These and other objects and advantages of the invention will be better understood from the accompanying drawings and the detailed description of preferred embodiments set forth below.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a motor vehicle fuel system comprising a vapor recovery assembly within the scope of the present invention.
FIG. 2 is an enlarged, exploded perspective view of a fuel vapor recovery canister according to the invention and suitable for use in the system of FIG. 1.
FIG. 3 is a sectional view of the canister of FIG. 2, shown assembled with adsorbent material and mounted, taken along line 3--3 of FIG. 2.
FIG. 4 is a plan view of the canister of FIGS. 2 and 3 showing details of the end cap.
FIG. 5 is a plan view of either of the two screens of the fuel vapor recovery canister of FIGS. 2 and 3.
FIG. 6 is a sectional view of the screen of FIG. 5, taken along line 6--6 of FIG. 5.
FIG. 7 is a sectional view of the screen of FIG. 5, taken along line 7--7 of FIG. 5.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to the system of FIG. 1, a vehicle fuel tank or reservoir 10 has a vent line 12 extending to a fuel vapor recovery assembly 14. Canister 14 contains an adsorbent for fuel vapors admitted through vent line 12 from the fuel tank 10. Canister 14 is open to the atmosphere, either directly or through a series of one or more like canisters, suitable valving, etc. T-connection 16 connects vent line 12, at a point intermediate the fuel tank and the fuel vapor recovery canister, to line 18. Controllable valve 20 is positioned in line 18 intermediate T-connection 16 and the vehicle engine 22. Suitable logic for automatic control of valve 20 will be apparent to the skilled of the art in view of the present disclosure. Thus, for example, valve 20 typically will be closed during refilling of the fuel tank and while the engine is not running such that vapor pressure within the fuel tank will be vented through the T-connection 16 to the adsorbent material in canister 14. This also would prevent the build up of combustible fuel vapors in the air intake manifold of the engine. To ensure that fuel vapors within the tank are displaced to the atmosphere through the on-board vapor recovery canister of the invention during refilling of the fuel tank, the fuel filler neck of the tank may be provided with a ring seal or other means of forming a fluid-tight seal with the fuel pump nozzle during the filling process. Valve 20, as noted above, would be closed during such refilling of the tank such that the only route to the atmosphere for fuel vapors within the tank would be through the recovery canister.
During engine operation, valve 20 normally would be open and line 18, being connected to the air intake system of engine 22, would draw a vacuum in line 12. Since the canister 14 is, directly or indirectly, opened to the atmosphere, a flow of atmospheric air will be induced through canister 14, line 12 and line 18 to the engine. Such flow of atmospheric air will over a period of operation striP fuel vapor from the adsorbent material, thereby recharging the adsorbent. Any number of canisters of the type disclosed herein can be connected to one or more vent lines from a fuel tank either in series or in parallel to provide the desired level of fuel vapor emissions control, subject of course to constraints on available space, fluid flow impedance, etc. For use in a motor vehicle, of course, the added weight of such canisters is a significant consideration since it impacts fuel economy, acceleration, etc. In this regard it will be apparent that numerous different valving strategies are Possible and the most apPropriate selection will be based upon the intended use of the system. It will be within the skill of the art in view of the present disclosure to employ suitable valving to control the flow of fuel vapors and purging air through vent lines connecting the fuel tank, fuel vapor recovery canister(s), atmosphere and vehicle engine.
Referring now to FIGS. 2 through 7, a fuel vapor recovery canister 25 according to a preferred embodiment of the invention is shown to comprise canister housing 30. Housing 30 is seen to be open ended in that fluid flow port 32 is formed in bottom wall 34 of the housing and the opposite end 36 of the housing is open. It will be understood that reference to wall 34 of the housing as a bottom wall is a reference of convenience only and is based on the orientation of the recovery canister in FIGS. 2 and 3. It is not intended to be any limitation on the orientation of the canister in actual use. The canister can be used in either axial orientation. That is, either Port 32 in the bottom wall or port 49 in the end cap of the canister can be connected to the source of fuel vapors and the other left open to the atmosphere. It will be appreciated that "open to the atmosphere" as used herein means either opened immediately to the atmosphere or indirectly through one or more additional such canisters, conduit and/or valving.
Canister 25 further comprises a pair of substantially identical screens 38, 39. The screen 38 is adapted by dimension and shape to be dropped into the canister housing 30 in the orientation shown, whereby with application of small degree of pressure it will snap under and be held by retaining tabs 41-44. More specifically, upper edge 40 of screen 38 will seat under tabs 41-44.
In assembling the canister, suitable adsorption means 29 for releasably adsorbing fuel vapor is loaded into the canister above screen 38. As discussed above, various suitable adsorption means are well known to the skilled of the art and include, for example, extruded pellets of activated carbon. Thereafter, screen 39 would be assembled into the canister housing above the adsorption means in the orientation shown, i.e. with its concave side open to the adsorption means.
According to the preferred embodiment shown in FIGS. 2 through 7, the inside walls of canister housing 30 are very slightly tapered. This allows ease of manufacture of the canister by injection molding means by reducing the difficulty of extraction of the molding tool from within the canister housing. Suitable resilient materials are well known to the plastic molding art which will allow withdrawal of the molding tool notwithstanding the slight interference of retention tabs 41-44. The screens 38, 39 preferably are made of like resilient material such that flange-like side wall 45 extending around the perimeter of screen 38 will compress radially inwardly facilitating generally continuous contact between edge 40 of screen 38 and the interior side wall 46 of the canister housing 30. Since such interior side wall 46 preferably is only slightly tapered, as noted above, peripheral edge 50 of upper screen 39 also forms substantially complete contact with the interior side wall 46. In this way, the canister housing 30 and the two screens 38, 39 cooperate to contain the adsorption means.
Coil spring 47 is positioned above upper screen 39 within the canister housing 30. End cap 48 forms a fluid tight closure of open end 36 of the canister housing, i.e. forms a fluid tight seal continuously around the perimeter. End cap 48 comprises a fluid flow port 49 therethrough for communicating a flow of fluid, such as fuel vapor, into and out of the housing. End cap 48 can be attached and sealed to the canister housing 30 by any of various means well known to the skilled of the art including, for example, friction welding which is preferred, adhesive bonding, a close tolerance snap fit, etc.
It is generally more difficult, particularly in an automated assembly operation, to friction weld or otherwise attach end cap 48 to the canister housing 30 if coil spring 47, otherwise in the free state, is being simultaneously axially compressed by the end cap. In addition, if the partially assembled vapory recovery canister is to be transported to a friction welding station (or other end cap attachment station) after positioning of the coil spring, but with the coil spring in the free state, there would be risk of loss of and/or change of position of the end cap and/or coil spring during such transportation. According to the present invention, however, inwardly opening grooves 51-54 are provided in the interior surface 46 of canister housing 30 at its upper end. Below each of these grooves can be seen a generally triangular area of faring into the plane of the adjacent surface of interior surface 46. When coil spring 47 is assembled into the canister housing 30, four arcuate portions of the uppermost coil 55 of the spring are received into corresponding ones of the grooves 51-54. Thereafter, the canister housing assembly can be transported for final assembly with end cap 48 with reduced risk of dislocation and loss of the various components.
The grooves 51-54 can be formed during an injection molding process using techniques known to those skilled in the injection molding arts. Preferably such grooves are formed by means of slides, i.e. moveable portions of the molding tool, since this will facilitate withdrawal of the molding tool from the canister housing. Where the canister housing is essentially rectilinear with planar walls, as in the preferred embodiment of the drawings, the grooves generally will extend (circumferentially) only in a center area of each of the four planar wall segments of the canister since this is easier to accomplish using molding tool slides and since, in any event, the round coils of the coil spring will only contact the walls of the canister housing at those locations. It will be appreciated, however, that through means such as use of a collapsible core or the like, full circumference grooves can be formed, if desired.
Screens 38 and 39 comprise, respectively, mesh 35 and 37, preferably in substantially their entire lateral area. According to certain preferred embodiments, the screens further comprise axially outwardly projecting ribs. In the particular embodiment shown in FIGS. 2 through 7, each the screens used in the vapor recovery canister comprises four ribs 60 extending laterally from approximately the center of the mesh toward a corresponding one of the four corners of the screen. Ribs 60 extend axially outward, that is, away from the adsorbent material. Ribs 60 serve several distinct and advantageous purposes. Specifically, in the case of both the top screen 39 and bottom screen 38 the ribs reinforce the mesh portion thereof. Also, in bottom screen 38 the ribs act as a stand-off against the inside surface of bottom wall 34 of the canister housing to permit full, unrestricted flow of fuel vapors to port 32. Also, in upper screen 39 the ribs 60 form a retaining lock for the innermost coil 56 of coil spring 47. That is, the inside surface of coil 56 seats against the outer end of the ribs, as best seen in FIG. 3. This aids in achieving uniform lateral distribution of compression of the adsorption bed and eliminates side-to-side shifting of the coil spring at its lower end. Also, the ribs of screens 38 and 39 facilitate automated assembly of the vapory recover canister in that they provide a convenient location to be gripped by automated assembly mechanisms. The tapered, radius corners of the screens also facilitate automated insertion thereof into the tapered canister base while still providing effective, substantially complete peripheral contact between the screen and the inside surface of the canister housing 30, as mentioned above, to form an effective barrier against migration and loss of adsorption particulate. It will be appreciated that the common design of top and bottom screens 39, 38 in the embodiment of the drawings results in less complexity and, hence, reduced cost of manufacture and assembly of the canister.
Preferably screens 38, 39 are formed by close tolerance injection molding techniques well known to the skilled of the art. Suitable materials include many well known and commercially available plastic materials such as nylon, which is preferred. In any event, all materials employed for the screens and other components of the canister must be compatible with the fuel vapors which will be encountered during use of the canister.
Regarding coil spring 47, it will be appreciated that automated assembly means can be used which grab upper coil 55 of the spring at locations circumferentially offset from the four locations which will be received, one each, in the corresponding grooves 51-54 in the inside surface 46 of the canister. Such assembly means can insert the spring into canister housing 30 since a gap will exist between the coil 55 and the interior side wall 46 of the housing at the four corners of open end 36 of the housing. The coil spring 47 can be fabricated either of suitably resilient plastic or, more preferably, of spring steel. The application of a compressive load against the upper screen 39, whereby the adsorption means is under constant compressive force, acts to prevent shifting and migration of adsorption particulate which otherwise might occur do to vibration, etc. during possibly many years of use.
Regarding end cap 48, the preferred embodiment shown in FIGS. 2, 3 and 4 can be seen to comprise four axially inwardly extending blocks or pockets 62 which can serve as attachment points for friction welding means. It will be appreciated, however, that alternative means are possible for holding the end cap. For example, means can be provided to expand outwardly against the inside of central port 49 to hold end cap 48 during friction welding. End cap 48 further comprises, as a preferred feature, nubbins 64 extending downwardly into the canister housing 30. Nubbins 64 are sized and positioned to fit into the aforesaid gap at the corners of open end 36 of housing 30 between uppermost coil 55 of coil spring 47 and the interior surface 46 of the housing. Nubbins 64 serve to temporarily position the cap and prevent its dislocation during transport of the assembled canister prior to friction welding of the end cap to the housing 30. Preferably a clearance of at least about 0.02 inch (0.5 mm) is provided between the nubbins and the canister housing 30 such that they do not unduly interfere with the friction welding operation. This consideration, of course, may not apply where other methods are to be used for attaching the end cap 48 to housing 30.
The preferred embodiment of the invention depicted in FIGS. 2 through 7 further comprises means for mounting same to a motor vehicle chassis or the like. Specifically, pocket 70 is formed on the exterior surface of canister housing 30 and flange-like tab 72 provides aperture 73 for a bolt, screw, etc. Innumerable alternative means for mounting canisters of the invention will readily apparent to the skilled of the art in view of the present disclosure. Similarly, means will be apparent to the skilled of the art for mounting such canisters one to another where the configuration of the available mounting space allows such "ganging" of the canisters.
While the above provides a full and complete disclosure of the invention in terms of certain preferred embodiments, it will be apparent to those skilled in the art in view of this disclosure that various modifications and alternate constructions and embodiments may be employed without departing from the scoPe of the invention as defined by the appended claims.
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A fuel vapor recovery canister in a motor vehicle fuel system comprising: adsorption means for releasably absorbing fuel vapor; an open-ended housing for the adsorption means, the housing comprising end closure means forming a fluid tight seal with an open end of the housing and having a first fluid flow port therethrough for communicating a flow of fluid into and out of the housing, and a second fluid flow port remote from the first and open to the atmosphere, wherein the first and second fluid flow ports are in communication with each other within the housing through the adsorption means; a first barrier means within the housing for separating the adsorption means from the first fluid flow port; second barrier means within the housing for separating the adsorption means from the second fluid flow port, the housing, first and second barrier means cooperating to contain the adsorption means; and biasing means, such as a coil spring, positioned intermediate the end closure means and the first barrier means for biasing the barrier means toward the adsorption means to place the adsorption means in compression.
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REFERENCE TO RELATED APPLICATION
[0001] The present application is related to two patents entitled “Power Supply for Providing Instantaneous Energy during Utility Outage” Dated: Feb. 1, 2000, U.S. Pat. No. 6,020.657 and Dated: Mar. 20, 2001, U.S. Pat. No.: 6,204,572, by the same inventor but with no assignee.
FIELD OF INVENTION
[0002] This invention relates to rotating machines and more specifically to transfer kinetic energy from one rotating machine to another thru electromagnetic or magnetic fields. The invention relates also to rotating machines that need to increase or decrease rotational speed from one machine to another with the ability to control the output speed electromagnetically for providing accurate speed to sensitive machines such as generators.
BACKGROUND OF THE INVENTION
[0003] The need to reduce or increase the speed from one rotating machine to another is desired in many machines. The conventional method to transfer rotational energy from one rotating machine to another is done by using gearboxes. The main problem with using a gearbox is its reliability because the matching gears are under constant mechanical friction, which creates heat and weariness. Gears are also noisy, require constant lubrication and have a limitation on the maximum gear ratio that can be achieved between two matching gears. Usually the limit is less than 10. Furthermore, using a gearbox gives a fixed speed ratio between the input speed to the output speed that depends on the pitch diameter ratio between the two matching gears and therefore once the speed ratio has been determined, it is impossible to change it. If the input speed fluctuates, the output speed fluctuates as well. Anther existing method to replace a gearbox is to use an eddy current clutch, but its major disadvantage is its low efficiency that creates a great amount of heat, and thus it usually operates for just a few seconds. Machines such as generators that are required to provide accurate and fixed power and frequency to sensitive equipment such as computers, data processing, communication and many other sensitive systems, need a very accurate rotational speed. If we will turn a generator by a gas or diesel engine thru a gearbox, it will be impossible to maintain a fixed rotational speed on the generator due to irregularities in fuel supply to the engine or due to load changes. However, if we will turn the engine at a higher speed than the generator and we will use an electromagnetic transmission to transfer the required kinetic energy from the engine to the generator, as described in this invention, it is possible to provide an accurate speed to the generator even if there are load changes or engine irregularities.
[0004] U.S. Pat. No. 6,020,657 discloses uninterrupted power supplies using an AC motor to turn the flywheel and at the instant of a power outage, the AC motor becomes an Electromagnetic Clutch. This kind of clutch is not efficient and requires too much power to produce the required torque. In addition, this kind of clutch requires an expensive Variable Frequency Drive to control the speed.
[0005] U.S. Pat. No. 6,204,572 is similar to the previous patent but instead of using the AC motor as a clutch between the flywheel and the synchronous machine, we are using a combination of induction coils and induction bars facing each other axially. This kind of clutch creates axial forces between the synchronous machine and the flywheel that requires big clearances between the two parts of the clutch, which means a less efficient clutch and requires special expensive bearings to carry the axial forces. In addition, the magnetic loop for the magnetic flux is long and not efficient.
[0006] There is a need for a reliable, simpler and more effective transmission system which can efficiently transfer rotational speed with no mechanical friction, noise or limit on the speed ratio with the possibility to control and regulate the output speed, and that will be smaller and lighter than a gearbox. The present invention is describing such a transmission.
SUMMARY OF THE INVENTION
[0007] The objective of this invention is to provide a reliable and continuous speed transmission at any required speed ratio, with the capability to control and regulate the output rotating speed to sensitive or critical equipments. This invention can replace gear-box transmissions very effectively while simplifying the design, improving durability and maintaining an accurate output speed even while the input speed is fluctuating.
[0008] This invention utilizes three main components: 1. the high speed disc that is connected directly to the primary rotating machine which could be an electric motor, rotating shaft or any kind of engine. 2. The low speed disc that contains the electromagnetic coils and is connected directly to the machine that its speed we need to control. 3. The split core transformer that, thru electromagnetic induction coils, it is possible to transfer AC electrical power from a stationary primary transformer coil to a secondary rotating transformer coil.
[0009] The electromagnetic transmission or clutch that is presented in this patent is described in FIG. 1 to FIG. 8. In order to transfer rotational torque from the high speed disc to the low speed disc, we need to energize electrically the electromagnetic coil that is attached to the low speed disc or to use permanent magnets. When the electromagnetic coil is energized, it creates a magnetic flux. The magnetic flux closes its path thru two radial, small air gaps between the high speed disc and the low speed disc. The high speed disc can move inside a circular slot in the low speed disc and the magnetic flux created either by an electromagnetic coil or by a permanent magnet attached to the low speed disc closes the magnetic path thru the two air gaps and thru the section of the high speed disc that is located between the two air gaps. The outer diameter of the high speed disc, in the section which rotates between the two air gaps, is made of ferromagnetic material and has axial open windows all around. Inside the windows are embedded conductive materials such as aluminum or copper. When the high speed disc moves inside the electromagnetic field created by the coil inside the low speed disc, we get electrical current induced in the ferromagnetic bars between the windows due to the relative rotational speed between the two discs. The return path for the electric current will be thru the conductive material embedded inside the windows. Because of the electric current that passes in the ferromagnetic bars which are under magnetic flux, we get an electromagnetic force between the low speed disc and the bars. This force provides the electromagnetic kinetic energy transmission or clutch between the high speed disc and the low speed disc. It is possible to control the amount of kinetic energy that we would like to transfer from one disc to the other by controlling the electrical current to the electromagnetic coils.
[0010] The electrical power to the electromagnetic coil is transferred thru a split core transformer. The primary coil of the split core transformer is a stationary coil that is energized with AC power. The secondary coil is attached to the low speed disc and faces the primary coil thru a small air gap. Electrical power is induced from the primary coil to the secondary coil and the AC power induced in the secondary coil is rectified by two power blocks. Each power block contains two diodes and the total four diodes create a rectifying bridge. The rectified power from the power blocks energizes the electromagnetic coil which provides the required force and torque to transfer kinetic energy from the high speed disc to the low speed disc or from the high speed disc to a linear rail—in the case of a linear motor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Following are different kinds of applications for using the electromagnetic transmission or clutch.
[0012] [0012]FIGS. 1 and 2 are drawings of the rotary electromagnetic transmission assembly, using electromagnetic coils to create the required magnetic coupling between the high speed disc and the low speed disc.
[0013] [0013]FIGS. 3 and 4 describe an option to provide high torque electromagnetic transmission from a rotating high speed disc to a linear rail. This kind of transmission is fit for applications such as electromagnetic trains and high energy launch systems.
[0014] [0014]FIGS. 5 and 7 show different methods to transfer rotational kinetic energy from a high speed disc to a low speed disc. These methods are efficient and effective for cases that require a high speed ratio between the input to the output. The pitch diameter between the two discs can be designed for an optimal speed ratio to achieve high efficiency performance for a given speed ratio. FIG. 6 is a side view of the high speed disc that is shown in FIGS. 5 and 7.
[0015] All of the above descriptions describe the use of the electromagnetic coils to create the magnetic fields required to transfer the kinetic energy. However, it is possible to replace the electromagnetic coils with permanent magnets and to achieve the same result, except the option to control the amount of kinetic energy to be transferred. An example of how this can be done is given in FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] A description of the invention is provided with figures using reference designations. Referring to FIG. 1, the “electric motor”— 2 turns the “high speed disc”— 3 thru a “mechanical coupling”— 18 . If we will apply AC electrical power to the “primary coil”— 8 which is part of the “split core transformer” the power will be induced to the “secondary coil”— 9 of the split core transformer and faces the primary coil thru a small air gap. The “split core transformer” contains the following components: “laminations”— 10 a and 10 b , embedded inside “bearing support”— 6 and “low speed disc”— 4 , “primary coil”— 8 embedded inside a radial groove in the “laminations”— 10 b and “secondary coil”— 9 embedded inside a radial groove in “laminations”— 10 a . The AC power that is induced in the “secondary coil”— 9 is rectified to a DC power by the “power blocks”— 11 a and 11 b . The DC power from the “power block” energizes the “electromagnetic coil”— 7 , that provides the magnetic field to the electromagnetic coupling between the “high speed disc”— 3 and the “low speed disc”— 4 . It is possible to control the speed of the “low speed disc” by sensing the output speed and regulating the current and voltage to the “primary coil”— 8 .
[0017] The bearings 13 a and 13 b support the “high speed disc”— 3 and bearings 12 a and 12 b support the “low speed disc”— 4 . The bearings 13 a and 13 b are assembled inside a “bearing housing”— 5 and the bearings 12 a and 12 b are assembled inside a “bearing housing”— 6 . “Bearing housings”— 5 and 6 are attached to the “base”— 1 . It is possible to attach the “bearing housings”— 5 and 6 to the base thru “hinges”— 17 a and 17 b as shown in FIG. 2; this kind of “bearing housing” assembly eliminates any misalignment torque inside the bearings and prolongs the bearing's life.
[0018] [0018]FIG. 2 shows the windows on the ferromagnetic material of the “high speed disc”— 3 in the area that rotates between the two air gaps inside the slot in the “low speed disc”— 4 . FIGS. 1 and 2 show the “electrical conductive material”— 15 inserted inside the windows and bolted with screws 16 a and 16 b to the “high speed disc”— 3 .
[0019] Bearing 12 a , 12 b , 13 a and 13 b are preferably angular contact ball bearings such as SKF bearing 7036 to take radial loads as well as axial loads. Other kinds of bearings are also possible, including magnetic, electromagnetic, oil or air bearings.
[0020] The “power block”— 11 a and 11 b such as EUPEC #DD171N14K contain two diodes in each block. The “low speed disc” is made out of a ferromagnetic material such as SAE1018. The “electromagnetic coil”— 7 and the “primary” and “secondary” coils of the “split core transformer— 8 and 9 , is preferably made of copper wire with about 150 turns. However, the number of turns can change and it depends on the torque, the rotational speed that is required to transmit from high speed disc to low speed disc and the available input voltage to the electromagnetic coil.
[0021] Referring to FIGS. 3 and 4: The “electric motor”— 2 turns the “electromagnetic disc”— 3 thru “mechanical coupling”— 18 . The “electromagnetic disc”— 3 is mounted thru bearings 13 a , 13 b and is housed in “support”— 5 . Bearings 13 c , 13 d are housed in “support”— 4 . “Supports” 4 and 5 can move on top of “rail” 1 thru preferably sets of “wheels” 17 a , 17 b , 17 c and 17 d . The “wheels” have set of bearings: 16 a , 16 b , 16 c , 16 d , 16 e , 16 f and 16 g . The set of bearings have locks for positioning: 15 a , 15 b , 15 c and 15 d . It is not a must to use the wheels and the ball bearings in order for the supports 4 and 5 to move on top of “rail”— 1 , among the other options are: air bearings and magnetic bearings. The side view of the “rail”— 1 is shown in FIG. 4. The length of the rail is determined by the length travel required for a specific linear motor. The top section of the “rail”— 1 is positioned between two narrow air gaps inside a slot in the “electromagnetic disc”— 3 . The top section of the “rail”— 1 must be made of a ferromagnetic material and has array of opening windows. Inside the open windows are embedded “electrical conductive materials”— 6 , bolted to the “rail”— 1 with screws 14 a and 14 b. This invention shows a method of using the “split core transformer” as described above to transfer electrical power without using brushes. The “electromagnetic disc”— 3 has two sets of electrical coils, the “secondary coil”— 8 of the split core transformer and the “electromagnetic coil”— 6 that is embedded inside the radial slot in the “electromagnetic disc”— 3 and when energized it produces electromagnetic flux. The electromagnetic flux closes its magnetic path thru the two air gaps and thru the upper part of the “rail”— 1 which has the windows filled with the “electrical conductive material”— 6 . The “primary coil”— 9 of the split core transformer is embedded in a radial groove inside laminations positioned axially in “support”— 4 and the “secondary coil”— 8 is embedded in a radial groove inside laminations positioned axially in the face of the “electromagnetic disc”— 3 . A narrow air gap exists between “support”— 4 and the “electromagnetic disc”— 3 . The induced AC electric power in the “secondary coil”— 8 is rectified by the two “power blocks”— 10 a and 10 b . The rectified DC power from the “power blocks”— 10 a and 10 b is connected to the “electromagnetic coil”— 7 .
[0022] Referring to FIGS. 5 and 6: The “electric motor”— 2 thru the “mechanical coupling”— 18 , turns the “high speed disc”— 1 that is mounted thru bearings 13 e and 13 f that are housed in “support”— 5 and bearings 13 g and 13 h that are housed in “support”— 4 . The set of bearings 13 e and 13 f are locked to the “support”— 5 with “lock”— 12 c and the set of bearings 13 g and 13 h are locked to “support”— 4 with “lock”— 12 d . “Supports” 4 and 5 are bolted to the “base”— 16 thru “bolts”— 15 a and 15 b . The outer diameter of the “high speed disc”— 1 rotates inside a slot in the “low speed disc”— 3 with small axial air gap between the two discs. In FIG. 5, the shown slot is in a radial direction; however, it can be directed in any angle. The outer diameter of the “high speed disc”— 1 has windows shown in FIG. 6. The windows are field with an “electrical conductive material”— 6 such as aluminum or copper bolted to the high speed disc with “screws”— 17 a and 17 b . The material of the “high speed disc”— 1 , in the area where it is rotating inside the slot in “low speed disc”— 3 , must be made of a ferromagnetic material such as steel. The “low speed disc”— 3 has two sets of electrical coils, the “secondary coil”— 8 of the split core transformer and the “electromagnetic coil”— 7 that is embedded inside the radial slot and when energized it produces electromagnetic flux. The electromagnetic flux closes its magnetic path thru the two air gaps and thru the outer diameter section of the “high speed disc”— 1 which has the windows filled with the “electrical conductive material”— 6 . In order to transfer electrical power from a stationary coil to a rotary coil without using brushes, this invention shows a method of using the “split core transformer” as described above. The “primary coil”— 9 of the split core transformer is embedded in a radial groove inside “laminations”— 11 b that are positioned axially in “support”— 4 and the “secondary coil”— 8 is embedded in a radial groove inside “laminations”— 11 a that are positioned axially in the face of the “low speed disc”— 3 . The face of the laminations that contain the primary coil— 9 are opposite to the face of laminations that contain the secondary coil— 8 and between the two discs we have a narrow air gap. If we will apply AC power to the primary coil— 9 , electrical AC power will be induced in the “secondary coil”— 8 . The AC power from the secondary coil will be rectified by the two “power blocks”— 10 a and 10 b . The rectified DC power from the “power blocks”— 10 a and 10 b will energize the “electromagnetic coil”— 7 and magnetic flux will close the loop thru the two air gaps and thru the section of the “high speed disc” which is inside the slot. When the “electric motor” 2 or any other rotating shaft will turn the “high speed disc”— 1 it will rotate freely as long we will not apply electrical power into the “primary coil”— 9 and no magnetic flux exists. The moment we will have magnetic flux and the high speed disc will move inside it, the electromagnetic flux will create current inside the steel bars between the windows in the “high speed disc”— 1 and the return path of the electrical current will be thru the “electrical conductive material”— 6 inserted inside the windows. This current will interact with the magnetic flux and will create an electromagnetic force between the “high speed disc”— 1 and the “low speed disc”— 3 . This force can transfer kinetic energy from the “high speed disc”— 1 to the “low speed disc”— 3 and the amount of force depends on the strength of the electromagnetic flux that will be created by the “electromagnetic coil”— 7 and the relative speed between the “high speed disc”— 1 and the “low speed disc”— 3 . It is possible to control the rotational speed of the “low speed disc”— 3 by changing the current and voltage that we apply to the “primary coil”— 9 .
[0023] [0023]FIG. 7 is the same as FIG. 5 accept the “electric motor”— 2 is coupled to the “low speed disc. This kind of arraignment also provides an option to increase the speed from the “low speed disc”— 3 to the “high speed disc”— 1 .
[0024] Referring to drawing 8 : FIG. 8 shows the same concept as FIG. 1, except that the “electromagnetic coil”— 7 shown in FIG. 1 is replaced with a “permanent magnet”— 7 and the split core transformer is not required. The “permanent magnets”— 7 are made as a slotted ring. The slot creates a U section shape which is open in the axial direction, having one pole on the outer diameter and the opposite pole in the inside diameter of the slotted ring. It is possible to use other kind of permanent magnetic shapes to create the magnetic flux between the two rotating discs.
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Using electromagnetic or magnetic fields to transfer magnetic force from one rotating machine to another and a method of providing a smooth transition of kinetic energy between two rotating machines or between a rotating machine and a linear rail using a brushless electromagnetic coupling, with the possibility to fully control the speed of the rotating or moving machine by sensing the actual speed and regulating the electrical power to the electromagnetic clutch.
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BACKGROUND OF THE INVENTION
The present invention relates to a connection device or connector and, more specifically to a load connector equipped with an upstream cut-off device controlled by pilot signal contacts.
Certain industrial connectors are designed to electrically connect a charged device or machine with a supply source. This is the case, for example, of connections or connectors for charging a storage battery for vehicles or electrical devices. A connector of this type comprises two parts - the socket and the male plug. In the case of the above-described use these two parts obviously each comprise charged contact elements since one part is connected to the supply source and the other to the charged device such as batteries. Moreover, without the simultaneous connection of the plug and socket to a current source it may happen that they each perform interchangeable roles and are alternately or arbitrarily connected to a current source.
It is known to protect the female contacts of a socket of an industrial connector from accidental contact by means of a safety disk which covers the contacts in the rest state and uncovers them by means of a special movement prior to insertion of the corresponding male part.
OBJECT AND SUMMARY OF THE INVENTION
One of the objects of the present invention is to provide a charging connector in which both the socket and the plug are protected from possible contact by means of two safety disks.
This protection must also be automatic, i,e., it must not necessitate an auxiliary or supplementary operation which, if it were omitted, would result in the breakdown of the safety system. It is a further object of the invention to provide a device wherein protection is automatically ensured by essential disconnection operations. Accordingly, the invention relates to an electrical connector comprising a socket and plug equipped with contact elements and designe to be electrically connected together. This connector is characterized in that the socket and plug are each equipped with a safety disk comprising a corresponding number of openings and disposed in a relative position corresponding essentially to the contacts with which it is provided. Means are provided for temporarily locking each of these disks in the rest state in an angular position in which it conceals the corresponding contacts and special means and operations for inserting the plug in the socket enable the disks to be unlocked, the contacts to be moved relative to their respective disk so as to align the contacts of the socket and plug and the corresponding openings in the disks, and finally an electrical connection to be ensured between the contacts and the plug and socket retained in this position. Disconnection is achieved by reversing these operations, thereby returning the elements to their starting position.
Above a specific current intensity construction standards necessitate the mounting of an upstream cutoff device which is mechanically or electrically controlled in such a way that contacts are connected during an interruption in the supply and the contacts are separated after disconnections of the supply to avoid the formation of an electric arc.
In devices equipped with an electrically controlled cut-off device, the latter generally comprises a press switch which is electrically connected to the cut-off device or of at least one pilot signal contact. In the latter case, the pilot contact or contacts are disposed in such a way that when the plug is being inserted in the socket, the contacts are engaged in the following order: ground, phases, pilot signal contacts. As a result, the latter close the cut-off device after connection of the ground and phases. Conversely, during the unplugging operation the contacts are disengaged in the following order: pilot signal contacts, phases and ground --thereby cutting off the supply load before the power contacts are separated.
In the case of the conventional plug-socket connectors the unplugging operation is generally effected by manual pulling and the time separating the disconnection of the pilot signal contacts and the phase and ground contacts is directly associated with the rapidity of the movement. In addition, the operating time of the cut-off device can be very short and is sometimes insufficient. As a result, the phase contacts may be disconnected before the upstream connection is effected. It is therefore necessary to increase the time between the separation of the pilot signal contacts and the phase contacts, for example, by means of an additional essential operation.
Another object of the invention is to provide a connector equipped with an upstream cut-off device controlled by at least one pilot contact, characterized in that the plug and the socket are equipped with mating means disposed in such a way as to delay the separation of the power contacts, after separation of the pilot contacts to ensure that the cut-off device has sufficient operating time. Moreover, the cut-off device or pilot contact control system may develop a malfunction. For this reason, it is another object of the invention to provide means for enabling the plug to attain a given rest position in which all the contacts are disengaged.
To achieve this object it is proposed according to the invention to provide the plug and socket with means, for example, interlocking means (bayonet means) which are disposed in such a way that the plug and socket are temporarily immobilized relative to one another in a position in which a connection is not established; the power contacts being sufficiently far away from one another that during unplugging this position provides a cut-fff position for the power contacts even if the upstream cut-of device has not operated.
A device such as the latter can obviously be equipped with safety disks according to the invention to provide a device offering considerable safety of operation. However, it is also apparent that the safety disks according to the invention can be used with any other current connecting device or connector which does not comprise a pilot contact system.
BRIEF DESCRIPTION OF THE DRAWING
Other objects, features and advantages of the present invention will be made apparent in the course of the following description thereof which is provided with reference to the accompanying drawings, in which:
FIG. 1 is a diagrammatic plan view of a socket and plug according to the invention;
FIG. 2 shows an end view of the plug according to FIG. 1;
FIG. 3 shows an end view of the socket according to FIG. 1;
FIG. 4 is a partial longitudinal section of the plug and socket after the first insertion stage:
FIG. 5 is a plan view of the plug and socket in the engaged position;
FIG. 6 is a partial section of the plug and socket in the position shown in FIG. 5;
FIGS. 7a, b and c are diagrammatic views of a part of the contacts with the contacts in the disconnected position with the power contacts closed and with the pilot contacts disconnected and with all the contacts closed, and
FIG. 8 is a schematic diagram showing the socket and plug of the invention incorporated in a battery charging system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings, FIG. 1 shows a load connector equipped with a cut-off device 36 (shown in FIG. 8) which is disposed upstream and which is controlled by a pilot wire system. This connector consists of a socket 1 and a plug 2 designed to be inserted in the socket 1. The latter is equipped with a protective cover 3 and the plug is provided with a ring 4, the mode of operation of which will be described hereinafter. The socket and plug are equipped with conventional terminal pressure contacts and hereinafter are claimed as cooperative elements.
FIG. 2 shows an end view of the plug. The latter is provided with a number of pins 5a, 6a and 7a for the ground and phases and 8a and 9a for the pilot contacts (the pins are concealed and represented by perforated lines in the drawing). The socket (FIG. 3) is provided with corresponding contacts 5b-9b. Two safety disks 10 and 11 are mounted on the plug and socket, respectively. The disks 10 and 11 comprise openings 12a-16a and 12b-16b which are disposed essentially in the same manner as the pins 5a-9a and the contacts 5b-9b. The disks 10 and 11 are in an angular position such that the pins of the plug and the contacts of the socket are hidden.
The first connecting operation consists in inserting the plug 2 in the socket 3 until the disks 10 and 11 are in contact with one another. This position is shown in FIG. 4. The plug and socket are angularly positioned with respect to one another by means, for example, of an interlock system (bayonet system) comprising lugs 33b and 34b of the socket and grooves 33a and 34b of the plug (FIGS. 2 and 3), such that the openings 12a-16a of the disk 10 and the corresponding openings 12b-16b of the disk are disposed opposite one another.
The section of FIG. 4 is such that two pins and two socket contacts are represented. The pins of the plug are integral in rotation with a disk 17 which is pushed against the disk 10 by a flexible means such as a spring 18. The disk 17 is equipped with openings for the free passage of the pins. In addition, the disk 10 is locked in position by means of a notch 19 (FIGS. 2 and 4) in which a lug 20 of the plug is adapted to lodge and the disk 11 is locked in position by means of a washer 21 which cooperates, in a conventional manner by means of notches and lugs, with the disk 11. The washer 21 is urged into its locking position by a spring means 22. The leading end of the plug is moved into the position shown until it contacts the washer 21. The disks 10 and 11 are also equipped with openings 23a and 24a (FIG. 2) and mating lugs 23b, 24b (FIG. 3) which are designed to cooperate with one another and render the disks integral in rotation.
It is thus considered now to be apparent that in this position the disks 10 and 11 are locked in place and are thus united for rotation and furthermore, that their respective openings are disposed opposite one another. However, the locking means described above can obviously be varied in different ways. For example, to provide increased security, the locking device of the disk 10 may be replaced or another lug provided which is mounted in the disk 17 and caused by spring pressure to lodge in a corresponding opening provided in the disk 10; a mating lug or lugs mounted on and provided on the disk 11 being designed to push back and flatten the lug or lugs on the disk 17 by passing through the disk 10 when the two disks are applied one against the other. The lugs of the disk 11 and the openings in the disk 10 then preferably replace the means 23a, 24a, 23b, 24b thereby rendering the disks united for rotation.
The following operation is a slight translational movement of the plug in the socket, for example, of 5 mm. This operation, which is not shown in greater detail, makes it possible to unlock the disks 10 and 11. Indeed, the lug 20 of the plug has been advanced with the latter and it frees the opening 19 of the disk 10 which abuts against the disk 11; the spring 18 thus being slightly compressed. Similarly, the disk 11 is unlocked by pressing the leading edge of the plug, causing a slight withdrawal of the locking washer 21, against the withdrawal spring means 22. In the case of the locking system of disk 10 which is described as a variant, it is obvious that contact between the disks 10 and 11 suffices to unlock the same.
The trailing face of the disk 10 is equipped with two lugs 25a and 26a which are disposed diametrically opposite one another and which are represented by the perforated line in FIG. 2. Similarly, the rear face of the disk 11 is equipped with two lugs 25b and 26b (FIG. 3). The disk 17 and the isolating body of the socket are equipped with circular grooves 27a, 28a and 27b, 28b (FIGS. 2 and 3) designed to cooperate in rotation with the lugs 25a, 26a and 25b, 26b, respectively. For practical reasons, more specifically, as a result of the number and diameters of the contacts and openings in the safety disks, the contacts and openings are angularly offset with respect to one another in the rest position by an angle of 40°, both in the case of the plug and the socket. Similarly, the grooves 27a, 28a and 27b, 28b comprise an angular opening of 40°.
From the angular position represented in FIGS. 2 and 3 and after releasing the safety disk, the plug is rotated so as to align its pins 5a-9a with the corresponding openings 12a-16a, i.e., about 40° in the positive trigonometric sense when considering FIG. 2. This movement is guided by the bayonet type interlock system 33a, 34a and 33b, 34b. The power pins or phases rotate the disk 17. At the beginning of this rotation the grooves 27a and 28a of the disk 17 are in the position shown in FIG. 2 with respect to the lugs 25a and 26a, whereas at the end of this rotation these grooves are able to draw the lugs in this direction.
In this position obtained after this rotation it is obvious that the pins of the plug and the openings in the two safety disks are aligned.
If the above-mentioned rotation is continued by a further 40°, the grooves 27a and 28a of the disk 17 rotate the lugs 25a and 26a and thus the disks 10 and 11, which are integral in rotation. At the end of this second rotation or, more specifically, after a rotation of 80°, the disk 11 has rotated about 40° in the reverse trigonometric direction when considering FIG. 3 and the openings 12b-16b are opposite the contacts 5b-9b. The lugs 25b and 26b are then in abutment in the corresponding grooves 27b and 28b of the socket in an outer position which is the reverse of that shown in FIG. 3.
In this position the pins, contacts and openings in the disks are aligned. This position is a rest position of the plug where all the contacts are disconnected and corresponds to the position of the contacts in FIG. 7a. During unplugging this is a disconnection position of the power contacts even if the pilot circuit did not operate.
The final operation consists in moving the plug in the socket to obtain the connection of the contacts in the following order: ground 37, phases 39 and pilots 38 as shown in FIG. 8; the various contacts possessing relative longitudinal positions suitable for this purpose. To effect this latter movement the invention provides a rotating ring 4 which is disposed on the plug. This ring comprises two lugs 29a and 30a (FIG. 2) designed to cooperate with two inclines 29b and 30b (FIG. 3) provided in the socket. The latter possess the form shown in FIG. 5. After inserting the lugs 29a and 30a in the corresponding ends of the inclines, a suitable rotation of the ring 4 produces a translational movement of the plug in the socket until the lugs are lodged in the notches such as the notch 31 (FIG. 5) corresponding to the position of the contacts in FIG. 7b, i.e., the closed power contacts and open pilot contacts. This rotation of the ring 4 is continued until reaching the gripping position corresponding to the notch 32 shown in FIG. 5 and also in FIGS. 6 and 7c. During unplugging the reverse operations are carried out and the elements returned to their starting position.
The intermediate position obtained by means of the notch is especially important during unplugging. Indeed, rotation of the ring in the unplugging direction, causing a separating translational movement, is momentarily arrested or slowed down in the position shown in FIG. 7b. The pilot contacts are disconnected at this time. Separation of the power contacts is only effected after a specific period of time which enables the cut-off device disposed upstream to operate.
The above-mentioned intermediate position can be obtained in numerous ways, the object being to delay separation of the power contacts after separation of the pilot contacts. This delay can be obtained, for example, by mating means which are provided in such a way that the disconnection, on the one hand, of the pilot contacts and, on the other hand, of the power contacts, is achieved in the course of two different relativel movements of the plug and socket, each requiring a special manipulation, for example, a translational movement and a rotational movement produced by means of an interlock bayonet system or the like. In addition, the shape of the inclines may be completely different. Indeed, from the engaged position the inclines may comprise a first slope corresponding to the first translational movement and then a zero slope or gentler slope or even a slight reverse slope designed to arrest or slow down or reverse the translational movement, and then once again a slightly different slope, preferably similar to the first slope corresponding to the translational movement disengaging the power contacts.
It is obvious that numerous modifications can be employed without departing from the scope of the invention. More specifically, each time lugs and mating openings or guide inclines are mentioned, these may obviously be arbitrarily disposed on each of the cooperating parts or may even be replaced by corresponding means. Similarly, the ring 4 could be provided on the socket and not on the plug. In addition, if pressure type and contacts are preferable for the cut-off devices, other pin-type contacts and sockets, for example, could be used.
Moreover, the embodiment represented shows a junction or load connector equipped with an upstream cut-off device offering considerable reliability of operation and safety as a result of the safety disks. However, it is obvious that this device need only be equipped with one disk or may be used without a safety disk and also that the safety disks may be used in the case of all connectors in which the plug and socket are connected to a current source or in which the plug and socket are alternately or arbitrarily connected to a current source. This latter frequently applies to certain railroad connections.
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Electrical connectors comprising complementally formed plug and socket elements each of which include safety disks to conceal the contacts the plug and socket elements further having pilot contacts and power contacts as well as mating means arranged to delay the separation of the power contacts and interlock means for the respective elements capable of temporarily immobilizing the plug and power socket elements to provide a power cut-off for electrical engagement of said elements.
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FIELD OF THE INVENTION
The present invention relates generally to mobile radio systems.
BACKGROUND
The present invention is applicable to third generation mobile radio systems, for example, and in particular to mobile radio systems of the Universal Mobile Telecommunications System (UMTS) type.
Mobile radio systems are generally covered by standards and the corresponding standards published by the corresponding standards bodies may be consulted for more information.
FIG. 1 outlines the general architecture of mobile radio systems, essentially comprising:
a radio access network (RAN) 1 , and a core network (CN) 4 .
The radio access network comprises network elements such as base stations 2 (BS) and base station controllers 3 (BSC) and communicates with mobile terminals 5 via an interface 6 and with the core network 4 via an interface 7 . The core network 4 communicates with external networks (not specifically shown). Within the radio access network, the base stations communicate with the base station controllers via an interface 8 .
In a UMTS type system, the radio access network is called the UMTS terrestrial radio access network (UTRAN), a base station is called a Node B, a base station controller is called a radio network controller (RNC), and a mobile terminal is called a user equipment (UE). The interface 6 is called the Uu interface, the interface 7 is called the Iu interface, the interface 8 is called the Iub interface, and an interface 9 between radio network controllers is called the Iur interface. The interface 6 is also called the radio interface and the interfaces 7 , 8 and 9 are also called terrestrial interfaces.
The radio network controller that controls a given Node B is called the controlling radio network controller (CRNC) and has a load control and radio resource allocation role for each Node B that it controls. Thus FIG. 2 shows a CRNC controlling a set of Nodes B and the cells (not specifically shown) that are covered by those Nodes B.
For a given call relating to a given user equipment, there is a serving radio network controller (SRNC) having a control role for the call concerned. A Node B connected to the user equipment but not controlled by the SRNC communicates with the SRNC via the radio network controller that controls it, also known as the drift RNC (DRNC), via the Iur interface. This situation arises in macrodiversity transmission, also known as soft handover, for example (although not exclusively). Thus FIG. 3 shows an SRNC controlling a user equipment and communicating with the core network via the interface Iu, and a DRNC controlling the user equipment for radio links set up for cells controlled by that DRNC (these cells are not specifically shown).
The above systems must generally be able to support traffic whose quality of service (QoS) requirements may differ greatly. The quality of service architecture in a system such as the UMTS, for example, is defined in the Technical Specification 3GPP TS 23.107 published by the 3 rd Generation Partnership Project (3GPP). This quality of service architecture is based on support services characterized by quality of service attributes. There are various support services, for example radio access bearer (RAB) services, radio bearer (RB) services and Iu bearer services. There are various quality of service attributes, for example traffic class, maximum bit rate, guaranteed bit rate, transfer delay, traffic handling priority, etc. There are four traffic classes, namely conversational application, streaming application, interactive application and background application traffic classes. The quality of service attributes other than the traffic class may also be different for different types of service in the same traffic class; for example, for the conversational traffic class, the transfer delay for a telephone service is less than the transfer delay for a videophone service, which in turn is less than the transfer delay for a web browsing service, for example, for the interactive traffic class, for example. The transfer delay is generally specified only for the conversational and streaming traffic classes and the traffic handling priority is generally specified only for the interactive traffic class.
A model has been defined for the terrestrial interface communications protocols in which a distinction is drawn between a radio network layer corresponding to functions related to radio access, which are independent of the technology used for transport over the terrestrial interfaces, and a transport network layer corresponding to functions related to transport, which depend on the technology used for transport over the terrestrial interfaces. As a general rule, two types of data may be communicated using these protocols, namely data corresponding to traffic sent or received by a user equipment (also known as user data), and data corresponding to signaling, necessary for the operation of the system. There are two types of signaling, namely signaling related to the radio network layer and signaling related to the transport network layer.
The signaling relating to the radio network layer corresponds to the following protocols, for example, which are also known as application protocols:
for the Iu interface, the Radio Network Application Part (RANAP) protocol, defined for example in the Technical Specification 3GPP TS 25.413 published by the 3GPP, for the Iub interface, the Node B Application Part (NBAP) protocol, defined for example in the Technical Specification 3GPP TS 25.433 published by the 3GPP, and for the Iur interface, the Radio Network Subsystem Application Part (RNSAP) protocol, defined for example in the Technical Specification 3GPP TS 25.423 published by the 3GPP.
The RANAP protocol includes signaling relating to radio access bearer (RAB) set-up. The NBAP protocol includes signaling relating to radio link set-up for cells controlled by the SRNC. The RNSAP protocol includes signaling relating to radio link set-up for cells controlled by the DRNC.
Quality of service management in the above kind of system generally comprises quality of service management linked to radio access, which is independent of the technology used for transport over the terrestrial interfaces, and quality of service management linked to transport, which depends on the technology used for transport over the terrestrial interfaces.
Quality of service management linked to radio access is typical of code division multiple access (CDMA) systems, for example the UMTS, and includes mechanisms such as radio admission control, selection of appropriate transport formats on transport channels, etc. The exchanges of signaling defined in the application protocols outlined hereinabove generally enable the network elements concerned of the UTRAN to determine the quality of service constraints necessary for executing these quality of service management mechanisms linked to radio access. The main network element of the UTRAN affected by implementing quality of service management mechanisms linked to radio access is the RNC, in its SRNC role. This is because, on the basis of quality of service parameters that are signaled to it by the core network, using the RANAP protocol, the SRNC can decide which type of service is required and therefore translate the quality of service parameters into parameters that may be used to set up radio links between Nodes B and user equipments, if necessary via one or more DRNC, and then signal those parameters to the network elements concerned, namely the Node B, using the NBAP protocol, and the DRNC, using the RNSAP protocol.
Transport over the terrestrial interfaces is generally in packet mode to optimize the use of resources available for transmission over those interfaces. Packet mode was originally intended for non-real-time services (having no strict priority and/or time delay constraints), and additional mechanisms, including quality of service management mechanisms, for example, were introduced subsequently to enable packet mode additionally to support real-time services (having strict priority and/or time delay constrains), for example voice services. In the case of the UMTS for example, it is also necessary to introduce the real-time concept for packet services to deal with the “soft handover” problem, i.e. that of requiring the RNC to supply the sending times of the data to the various Nodes B controlling the cells to which the mobile is connected. These sending times take the form of radio frame numbers, and thus limit the maximum delay authorized for the transmission of data between the RNC and the Node B. For reasons of efficient power control and radio admission control, for example, the maximum delay cannot be set too high.
One transport technology used in the UTRAN is the asynchronous transfer mode (ATM) technology based on asynchronous time division multiplexing of small packets of fixed size known as cells. The ATM technology is covered by standards and the corresponding standards published by the corresponding standards bodies may be consulted for more information. Suffice to say that an ATM network may be modeled by means of an ATM layer and an ATM adaptation layer (AAL) between the ATM layer and users. The ATM layer is connection-oriented and transmits cells between a source and a destination over a logical connection also known as a virtual channel (VC). For application of the ATM technology to transport within the UTRAN, a specific AAL layer called the AAL2 layer is used for user data. When a user equipment communicates with the UTRAN, a corresponding logical connection (called an AAL2 connection) is set up over one or more of the terrestrial interfaces concerned of the UTRAN. In the case of the ATM technology, the mechanisms for managing the transport quality of service include, for example, connection admission control (to decide if the transmission resources are sufficient to accept a new AAL2 connection request whilst maintaining the guaranteed quality of service), and scheduling (queuing) for multiplexing AAL2 connections within a virtual circuit, for example as a function of priority.
Technologies other than the ATM technology may be used in the transport network, for example the Internet Protocol (IP) technology. The IP technology is also covered by standards and the corresponding standards published by the corresponding standards bodies may be consulted for more information. Once again, mechanisms for managing the transport quality of service may be provided in the case of the IP technology.
The present invention relates more particularly to managing the quality of service linked to transport, and even more particularly to mechanisms enabling the network elements concerned of the UTRAN to determine the quality of service constraints necessary for implementing quality of service management. In the absence of such knowledge, or in the event of insufficient knowledge, this quality of service management cannot be implemented optimally and the quality of service may be degraded to an extent that users find unacceptable.
On the basis of radio access bearer (RAB) parameters signaled to it by the core network using the RANAP protocol, the SRNC can decide what type of service is required for a user equipment and therefore which quality of service should be used in the transport network to transmit user data for that user equipment in the downlink direction over the Iub interface to the Node B (respectively over the Iur interface to the DRNC).
A problem nevertheless remains, that of the Node B (respectively the DRNC) knowing which quality of service should be used in the transport network to transmit user data for a user equipment in the uplink direction over the Iub interface (respectively in the uplink direction over the Iur interface and/or the downlink direction over the Iub interface).
A first solution to this problem is as follows. In the case of a transport network using the ATM technology, the signaling relating to the transport network layer includes the Access Link Control Application Part (ALCAP) protocol as defined in ITU T Specifications Q.2630 1 and Q.2630 2 published by the International Telecommunications Union (ITU), for example, and corresponding to successive versions of the 3GPP standard, respectively version R99 (for the ITU-T specification Q.2630 1) and the versions R4 and subsequently R5 (for the ITU-T specification Q.2630-2). The ITU T specification Q.2630 2 defines a quality of service parameter called the AAL type 2 requested type path that may take one of the following three values, as a function of the type of service: “stringent”, “tolerant” and “stringent bi level”. This parameter is transmitted by the CRNC (respectively the SRNC) to the Node B (respectively the DRNC) and enables the Node B (respectively the DRNC) to determine, within limits defined by these values, the quality of service constraints applicable to uplink transmission of user data over the Iub interface (respectively uplink and downlink transmission over the Iur interface).
However, this first solution may be applied only from version R4 of the 3GPP standard. It is not applicable to the R99 version, or to the R5 version if the transport network uses the IP technology. For example, in the current version of the standard, and in the case of a transport network using the IP technology, the signaling relating to the transport network layer is such that the Node B (respectively the DRNC) does not know which quality of service should be used in the transport network for uplink transmission of user data over the Iub interface (respectively uplink transmission over the Iur interface and/or downlink transmission over the Iub interface). Also, the three values for the AAL type requested type path parameter (see above) do not necessarily differentiate sufficiently between the available types of service, and therefore do not necessarily allow optimum implementation of the quality of service management mechanisms.
A second solution to the above problem is as follows. Under version R99 of the standard, failing a standardized solution, it would be possible to use a “proprietary” mechanism in the Node B (respectively the DRNC) to configure the transport priority for each type of service over the Iub interface (respectively the Iur interface). For example, the Node B (respectively the DRNC) could, on the basis of parameters transmitted by the CRNC (respectively the SRNC) using the ALCAP protocol, determine which connections are associated with voice services and assign them a high transport quality of service, and conversely assign a lower transport quality of service to connections associated with other types of service (for example web browsing, ftp, dedicated signaling, videotelephony, etc.).
However, this second solution may be applied only if the Node B (respectively the DRNC) and the CRNC (respectively the SRNC) are from the same manufacturer. It cannot be applied if those network elements are from different manufacturers.
The present invention adopts another approach to solving this problem. The present invention is based in particular on the following observations. Some quality of service parameters, such as parameters representative of the transfer delay and/or traffic handling priority, as defined for example in the above-mentioned Technical Specification 3GPP TS 23.107, are very important in guaranteeing the quality of service, for example the transport quality of service, within this kind of network. Now, parameters of this kind are already used for quality of service management linked to radio access. However, under the current version of the standard, and as outlined above, for managing the quality of service linked to radio access, knowledge of these quality of service parameters remains essentially localized to the SRNC. This is because, as mentioned above, on the basis of radio access bearer (RAB) parameters that are signaled to it by the core network (using the RANAP protocol), the SRNC can determine which type of service is required for a user equipment. The SRNC can then translate those parameters into parameters that may be used to set up radio links between the Node B and the user equipment, if necessary via one or more DRNC, and then signal those parameters to the network elements concerned, namely the Node B, using the NBAP protocol, and the DRNC, using the RNSAP protocol. These parameters include, for setting up radio links between Nodes B and user equipments, parameters such as transport format combination set (TFCS) or transport format parameters, and, if needed for multiplexing by the DRNC on common or shared transport channels, parameters such as traffic class and traffic handling priority.
However, under the current version of the standard, such signaling of transport format parameters generally cannot indicate quality of service constraints for the transport network layer, and such signaling of the traffic class and the traffic handling priority is effected only at the Iur interface (and not at the Iub interface), and only in the case of common or shared transport channels (and not in the case of dedicated channels). Also, this kind of signaling cannot indicate the quality of service constraints for the transport network layer, at least in terms of transfer delay. In particular, in distinguishing between different conversational class services, it does not allow a distinction to be made between services that require a short transfer delay (for example telephone services) and services that may tolerate longer transfer delays (for example videophone services).
SUMMARY OF INVENTION
A particular object of the present invention is to solve some or all of the above-mentioned problems and/or to avoid some or all of the above-mentioned drawbacks. Another object of the present invention is to propose different mechanisms to allow the network elements concerned of the UTRAN to determine the transport quality of service constraints needed to manage the quality of service. A more general object of the present invention is to improve and/or to simplify quality of service management in these systems.
One aspect of the present invention consists in a method of managing quality of service in a mobile radio network in which protocols for communication over terrestrial interfaces comprise a radio network layer and a transport network layer and quality of service management includes quality of service management linked to the radio network layer and quality of service management linked to the transport network layer, said method comprising:
a step in which a first network element signals to a second network element by means of the radio network layer signaling protocol at least one parameter representative of transport quality of service or of quality of service for the transport network layer, and a step in which the second network element uses said at least one parameter for transport quality of service management.
According to another feature, said first network element is a controlling radio network controller.
According to another feature, said second network element is a Node B or a base station.
According to another feature, said radio network layer signaling protocol is a Node B Application Part protocol applicable to the Iub interface between the controlling radio network controller and the Node B.
According to another feature, said second network element uses said at least one parameter for transport quality of service management for uplink transmission over the Iub interface between the controlling radio network controller and the Node B.
According to another feature, said first network element is a serving radio network controller.
According to another feature, said second network element is a drift radio network controller.
According to another feature, said radio network layer signaling protocol is a radio network subsystem application part signaling protocol applicable to the Iur interface between the serving radio network controller and the drift radio network controller.
According to another feature, said second network element uses said at least one transport quality of service management parameter for uplink transmission over the Iur interface between the serving radio network controller and the drift radio network controller and/or downlink transmission over the Iub interface between the drift radio network controller and the Node B.
According to another feature, said at least one parameter representative of transport quality of service is a specific parameter intended to indicate a transport quality of service level.
According to another feature, said at least one parameter representative of transport quality of service is at least one radio access bearer parameter that may also be used as a transport quality of service parameter.
According to another feature, said at least one radio access bearer parameter that may also be used as a transport quality of service parameter is the transfer delay.
According to another feature, said at least one radio access bearer parameter that may also be used as a transport quality of service parameter is the traffic handling priority.
According to another feature, said at least one radio access bearer parameter that may also be used as a transport quality of service parameter is the traffic class.
According to another feature, said at least one radio access bearer parameter that may also be used as a transport quality of service parameter is copied or translated from the RANAP protocol to the NBAP protocol, respectively from the RANAP protocol to the RNSAP protocol.
According to another feature, said at least one parameter representative of transport quality of service is at least one parameter that may be associated with a transport quality of service level or at least one radio access bearer parameter that may also be used as a transport quality of service parameter.
According to another feature, said at least one parameter that may be associated with a transport quality of service level or at least one radio access bearer parameter that may also be used as a transport quality of service parameter is a time adjustment parameter, the lowest values of said parameter being assigned to connections having the highest transfer delay and/or traffic handling priority constraints, and the highest values of said parameter being assigned to connections having the highest transfer delay and/or traffic handling priority constraints.
According to another feature, said time adjustment parameter is the time of arrival window start parameter.
According to another feature, said at least one parameter that may be associated with a level of transport quality of service or at least one radio access bearer parameter that may also be used as a transport quality of service parameter includes at least one parameter representative of the number of dedicated channels allocated to a connection, a high number of dedicated channels being allocated to connections having high transfer delay and/or traffic handling priority constraints, and a lower number of dedicated channels being allocated to connections having lower transfer delay and/or traffic handling priority constraints.
The present invention also consists in a network element comprising means for implementing the above method.
According to another feature, said network element is a controlling radio network controller.
According to another feature, said network element is a serving radio network controller.
According to another feature, said network element is a drift radio network controller.
According to another feature, said network element is a Node B.
Other objects and features of the present invention will become apparent on reading the following description of one embodiment, given with reference to the appended drawings, in which:
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 , described above, shows the general architecture of a mobile radio system such as the UMTS for example, and
FIGS. 2 and 3 , described above, show the CRNC, SRNC, and DRNC roles of an RNC.
DETAILED DESCRIPTION
Different embodiments of the present invention are described hereinafter.
In a first embodiment, one or more new parameters may be introduced into one or more signaling messages sent from the CRNC to the Node B using the NBAP protocol (respectively from the SRNC to the DRNC using the RNSAP protocol). By means of the new parameter(s), the CRNC (respectively the SRNC) is able to assign a high level of transport quality of service to certain types of service (for example types of service having high delay and/or priority constraints) and a lower transport quality of service level to other types of service (for example types of service having less strict delay and/or priority constraints). For example, a high level of transport quality of service may be assigned to voice services and a lower transport quality of service level may be assigned to other types of service. Intermediate quality of service levels may also be provided, in sufficient numbers to allow sufficient differentiation of types of service and thus optimum quality of service management. For example, the new parameter(s) may be transmitted in a message such as the “Radio Link Setup Request” message sent from the CRNC to the Node B using the NBAP protocol (respectively from the SRNC to the DRNC using the RNSAP protocol).
In a second embodiment, one or more new parameters for indicating transport quality of service parameter values for each type of service may be introduced into one or more signaling messages sent from the CRNC to the Node B using the NBAP protocol (respectively from the SRNC to the DRNC using the RNSAP protocol). The new parameter(s) may be derived from the radio access bearer (RAB) parameters sent to the SRNC using the RANAP protocol, for example. The RANAP protocol includes sending the following RAB parameters from the core network to the SRNC:
traffic class, transfer delay for conversational or streaming class services, and traffic handling priority for interactive class services.
For example, the new parameter(s) may correspond to one or more traffic class, transfer delay, and traffic handling priority parameters which may then be copied (or translated) from the RANAP protocol to the NBAP protocol, or one or more transfer delay and traffic handling priority parameters, which may then be copied (or translated) from the RANAP protocol to the RNSAP protocol (the traffic class parameter having already been copied from the RANAP protocol to the RNSAP protocol).
For example, the new parameter(s) may be sent in a message such as the “Radio Link Setup Request” message sent from the CRNC to the Node B using the NBAP protocol (respectively from the SRNC to the DRNC using the RNSAP protocol).
In a third embodiment, one or more existing parameters communicated to the Node B (respectively the DRNC) using the NBAP protocol (respectively the RNSAP protocol) may be used by the Node B (respectively the DRNC) to assign a high level of transport quality of service to certain types of service (for example types of service having strict delay and/or priority constraints) and a lower level of transport quality of service to other types of service (for example types of service having less strict delay and/or priority constraints).
A first example of these existing parameters is the time of arrival window start (TOAWS) parameter defined in the Technical Specification 3GPP TS 25.402, for example. Remember that dedicated frame protocols, as defined in the Technical Specifications 3GPP TS 25.425, 3GPP TS 25.427 and 3GPP TS 25.435, for example, are used for the transfer of user data over the terrestrial interfaces. Those protocols provide a data structure in accordance with a frame format and time adjustment and synchronization functions involving the TOAWS parameter, for example. To be more precise, a reception window is defined within which the time of arrival at the Node B of a frame sent by the RNC should occur. This window is defined by a time of arrival window start (TOAWS) defined relative to a time of arrival window end (TOAWE) in turn defined relative to a latest time of arrival (LTOA). If the time of arrival of a frame is before the TOAWS or after the TOAWE, then the Node B requests a time adjustment from the RNC. The object is to ensure that the Node B receives frames within a time appropriate for their retransmission at predetermined times over the radio interface, i.e. soon enough to be able to carry out the necessary processing before such retransmission, but not too soon, to avoid waiting times. A reception window of this kind is configured in the Node B when each radio link is set up; TOAWE and TOAWS values are therefore signaled by the CRNC (respectively the SRNC) to the Node B (respectively the DRNC) in different messages using the NBAP protocol (respectively the RNSAP protocol), such as the “Radio Link Setup Request” message for example.
According to one aspect of the invention, the CRNC (respectively the SRNC) may therefore assign the lowest TOAWS values to connections having a higher level of transport quality of service, for example, and the Node B (respectively the DRNC) may then use those TOAWS values for transport quality of service management. In other words, a time adjustment parameter such as the TOAWS parameter may be considered representative of transport quality of service in that it may be associated with a transport quality of service level or with at least one RAB parameter that may itself be used as a transport quality of service parameter. The CRNC (respectively the SRNC) may for example assign a TOAWS value of 10 ms to connections having a high level of transport quality of service (such as connections for voice services, for example), or a higher TOAWS value to connections having a lower level of transport quality of service, and signal that value to the Node B (respectively the DRNC), for example in the NBAP (respectively the RNSAP) “Radio Link Set Up Request” message. The Node B (respectively the DRNC) then assigns a high level of transport quality of service to connections having the lowest TOAWS values or a lower level of transport quality of service to connections having higher TOAWS values.
A second example of an existing parameter is the number of dedicated channels (DCH) assigned to a connection. As is known in the art, the CRNC (respectively the SRNC) may assign a plurality of dedicated channels to connections having a high level of transport quality of service (such as connections for voice services, for example) or a single dedicated channel to connections for other types of service having a lower level of transport quality of service. For example, for speech using adaptive multi-rate (AMR) coding, three different transport channels are generally used, one for class A bits, one for class B bits and one for class C bits, where the three classes of bits correspond to different levels of importance of the bits. See also, for example, the Technical Specification 3GPP TS 34.108. The CRNC (respectively the SRNC) may then signal the number of dedicated channels to the Node B (respectively the DRNC), for example in the NBAP (respectively the RNSAP) “Radio Link Setup Request” message.
According to one aspect of the invention, the Node B (respectively the DRNC) may then assign a high level of transport quality of service to connections such as connections for voice services assigned three dedicated channels or a lower level of transport quality of service to connections to which only one dedicated channel is assigned, for example. In other words, a parameter such as the number of dedicated channels assigned to a connection may also be considered representative of transport quality of service, in that it may be associated with a level of transport quality of service or at least one RAB parameter that may itself be used as a transport quality of service parameter.
To give another example, the SRNC may:
assign the conversational traffic class and allocate three dedicated channels to connections for voice services, assign the conversational traffic class and allocate a single dedicated channel to connections for other types of conversational class services (for example videophone services), assign other traffic classes to other connections, and signal those parameters to the DRNC, for example, in a “Radio Link Setup Request” message, for example. The DRNC may then assign a high level of transport quality of service to conversational class connections to which three dedicated channels have been assigned and lower levels of transport quality of service to other connections.
Common to all the above embodiments is the feature that each time the CRNC (respectively the SRNC) sets up a radio link associated with a type of service having high delay and/or priority constraints, it signals to the Node B (respectively the DRNC), using the NBAP protocol (respectively the RNSAP protocol), the fact that the transport connection associated with that particular radio link has a high level of transport quality of service (for example high delay and/or priority constraints). Conversely, each time that the CRNC (respectively the SRNC) sets up a radio link associated with a type of service having a lower level of transport quality of service (for example lower delay and/or priority constraints), it signals to the Node B (respectively the DRNC) using the NBAP protocol (respectively RNSAP protocol) the fact that the transport connection associated with that particular radio link has a lower level of transport quality of service (for example lower delay and/or priority constraints).
Using this information, the Node B (respectively the DRNC) may then implement transport quality of service management mechanisms in the uplink direction over the Iub interface (respectively the uplink direction over the Iur interface and/or the downlink direction over the Iub interface), to satisfy the transport quality of service constraints indicated by the CRNC (respectively the SRNC), for example delay and/or priority constraints. This enables delay constraints for voice services to be satisfied, for example.
The present invention also consists in a network element (for example a CRNC, a SRNC, a DRNC or a Node B) including means for implementing a method of the invention.
Since the particular implementation of such means do not represent any particular problem for the person skilled in the art, such means need not be described here in greater detail than by describing their function, as described above.
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One aspect of the present invention is a method of managing quality of service in a mobile radio network in which protocols for communication over terrestrial interfaces comprise a radio network layer and a transport network layer and wherein quality of service management includes quality of service management linked to the radio network layer and quality of service management linked to the transport network layer, said method comprising:
a step in which a first network element signals to a second network element by means of the radio network layer signaling protocol at least one parameter representative of transport quality of service or of quality of service for the transport network layer, and a step in which the second network element uses said at least one parameter for transport quality of service management.
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RELATED APPLICATIONS
This application, U.S. patent application Ser. No. 13/610,743 filed Sep. 11, 2012, is a continuation of U.S. patent application Ser. No. 13/396,538 filed Feb. 14, 2012, now abandoned.
U.S. patent application Ser. No. 13/396,538 is a continuation of U.S. patent application Ser. No. 13/181,326 filed Jul. 12, 2011, now abandoned.
U.S. patent application Ser. No. 13/181,326 is a continuation of U.S. patent application Ser. No. 12/837,254 filed Jul. 15, 2010, now abandoned.
U.S. patent application Ser. No. 12/837,254 is a continuation of U.S. patent application Ser. No. 12/080,096 filed Mar. 31, 2008, now abandoned.
U.S. patent application Ser. No. 12/080,096 claims benefit of U.S. Provisional Patent Application Ser. No. 60/922,041 filed Apr. 4, 2007.
The contents of all related patent applications listed above are incorporated herein by reference.
TECHNICAL FIELD
The present invention relates to materials for forming a textured coating on a target surface and, more particularly, to compositions of water-based texture materials and systems and methods for dispensing water-based texture materials from either aluminum or tin-plated steel containers.
BACKGROUND
The surfaces of drywall materials defining wall and ceiling surfaces are commonly coated with texture materials. Texture materials are coatings that are deposited in discrete drops that dry to form a bumpy, irregular texture on the destination surface. Texture materials are commonly applied using a hopper gun connected to a source of pressurized air. However, when only a small are is to be coated or an existing textured surface is repaired, texture materials are typically applied using an aerosol dispensing system.
An aerosol dispensing system for dispensing texture material typically comprises a container assembly, a valve assembly, and an outlet assembly. The container assembly contains the texture material and a propellant material. The propellant material pressurizes the texture material within the container assembly. The valve assembly is mounted to the container assembly in a normally closed configuration but can be placed in an open configuration to define a dispensing path along which the pressurized texture material is forced out of the container assembly by the propellant material. Displacement of the outlet assembly places the valve assembly in the open configuration. The outlet assembly defines a portion of the outlet path and is configured such that the texture material is applied to the destination surface in an applied texture pattern.
The texture material dispensed by an aerosol dispensing system may employ a solvent base, a water base, or a base containing a combination of water and water soluble solvents. A solvent based texture material dries quickly but can be malodorous and may require the use of complementary solvent cleaners for clean up. A water based texture material is typically not malodorous and can be cleaned using water but can take significantly longer to dry. A water/solvent based texture material can be cleaned using water, is typically not unacceptably malodorous, and has a dry time somewhere between solvent based and water based texture materials.
The propellant used by aerosol dispensing systems for texture materials may simply be a compressed inert gas such as air or nitrogen. More typically, the propellant used by aerosol dispensing systems is a bi-phase propellant material, including mixtures of volatile hydrocarbons such as propane, n-butane, isobutane, dimethyl ether (DME), and methylethyl ether.
At room temperature, bi-phase propellant materials typically exist in both liquid and vapor states within the container assembly. Prior to use, the vapor portion of the bi-phase propellant material is pressurized to an equilibrium pressure. When the valve assembly is placed in its open configuration, the vapor portion of the bi-phase propellant material forces the texture material out of the container assembly along the dispensing path.
When the valve assembly returns to its closed position, part of the liquid portion of the bi-phase propellant material changes to the vapor state because of the drop in pressure within the container assembly. The vapor portion of the propellant material returns the pressure within the container assembly to the equilibrium value in preparation for the next time texture material is to be dispensed from the aerosol dispensing system.
The container assembly typically comprises a metal tube structure formed by a rectangular metal sheet that is rolled and joined at two overlapping edges to form a seam. A bottom cap and end cap are welded or crimped onto the tube structure. The valve assembly and the outlet assembly are typically supported by the end cap.
Aerosol container assemblies are typically made of either tin-plated steel or aluminum. Aluminum container assemblies are typically used for water based or water/solvent based texture materials because the water in the formulation promotes corrosion and aluminum is less susceptible to corrosion. However, the costs and availability of aluminum and tin-plated steel aerosol container assemblies may differ.
The need thus exists for formulations of either water based or water/solvent based texture materials that may be used in either aluminum or tin-plated steel aerosol container assemblies without significant risk of corrosion.
SUMMARY
The present invention may be embodied as a system for dispensing texture material in a desired spray pattern that substantially matches an existing texture pattern on a target surface, comprising an aerosol dispenser, a concentrate, and a propellant material. The aerosol dispenser comprises a container assembly and an actuator assembly. The container assembly defines an inner surface, and the inner surface defines a main chamber and is at least in part a tin-plated steel. The actuator assembly defines an outlet opening having a cross-sectional area, where the cross-sectional area of the outlet opening is adjustable. The concentrate comprises a solvent/carrier comprising water, a resin/binder, filler material, a first anti-corrosion material, where the first anti-corrosion material is a phosphate ester and comprises approximately 0.5-2.0% by weight of the concentrate, and a second anti-corrosion material, where the second anti-corrosion material is sodium nitrite and comprises approximately 0.05-1.00% by weight of the concentrate. The concentrate and propellant material are disposed within the container assembly such that the water is exposed to the inner surface of the container assembly. At least one of the first and second anti-corrosion materials forms a film on the inner surface of the container assembly. The film inhibits corrosion of the inner surface of the container assembly. The cross-sectional area of the outlet opening is adjusted such that the propellant material forces the concentrate out of the outlet opening in a spray pattern that forms the desired texture pattern on the target surface.
The present invention may also be embodied as a method of dispensing texture material onto a target surface comprising the following steps. An aerosol dispenser is provided. The aerosol container comprises a container assembly defining an inner surface, where at least a portion of the inner surface is made of tin-plated steel. A concentrate is formed by mixing a solvent/carrier comprising water, a resin/binder, filler material, a first anti-corrosion material, where the first anti-corrosion material is a phosphate ester and comprises approximately 0.5-2.0% by weight of the concentrate, and a second anti-corrosion material, where the second anti-corrosion material is sodium nitrite and comprises approximately 0.05-1.00% by weight of the concentrate. The concentrate and a propellant material are arranged within the container assembly such that at least one of the first and second anti-corrosion materials forms a thin protective film on the inner surface. The aerosol dispenser is operated such that the propellant material forces the concentrate in a spray pattern that forms the desired texture pattern on the target surface.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a section view of a first example aerosol dispensing system for texture material of the present invention;
FIGS. 2A-2B are side elevation views depicting the process of using the aerosol dispensing system of FIG. 1 to apply texture material to a destination wall surface;
FIG. 3 is a section view of a second example aerosol dispensing system for texture material of the present invention; and
FIGS. 4A-4B are side elevation views depicting the process of using the aerosol dispensing system of FIG. 3 to apply texture material to a destination ceiling surface.
DETAILED DESCRIPTION
Referring initially to FIG. 1 of the drawing, depicted therein is an example aerosol dispensing system 20 constructed in accordance with, and embodying, the principles of the present invention. The example aerosol dispensing system 20 comprises a container assembly 22 , a valve assembly 24 , and an outlet assembly 26 . The container assembly 22 and valve assembly 24 define a main chamber 28 .
The main chamber 28 contains a liquid material 30 and a vapor material 32 . The liquid material 30 comprises texture material and propellant material in liquid form. The vapor material 32 comprises propellant material in vapor form. The liquid material 30 comprises propellant material in liquid form and a texture material concentrate. The combination of the liquid material 30 and the vapor material 32 in the container assembly 22 will be referred to as the contained material 34 .
When the valve assembly 24 is in a closed configuration, the flow of fluid out of the main chamber 28 is substantially prevented. However, the vapor material 32 pressurizes the liquid material 30 within the main chamber 28 such that, when the valve assembly 24 is in an open configuration, the vapor material 32 forces the liquid material 30 out of the main chamber 28 .
As perhaps best shown in FIG. 1 , the example container assembly 22 comprises a main member 40 , a bottom cap 42 , and an end cap 44 formed of tin-plated steel. The tin-plated steel used to form the main member 40 , bottom cap 42 , and end cap 44 comprises a thin sheet of steel coated on one side by an even thinner layer (approximately 0.5 microns) of tin.
The main member 40 is a rectangular sheet that is rolled into a cylinder and welded along a seam 50 to define first and second end openings 52 and 54 . The bottom cap 42 is a shaped tin-plated steel member that is crimped onto the cylindrical main member 40 to seal the first end opening 52 . The end cap 44 is also a shaped tin-plated steel member defining a mounting opening 56 ; the end cap 44 is crimped onto the main member 40 such that fluid may not flow through the second opening 54 between the end cap 44 and the main member 40 . The main member 40 , bottom cap 42 , and end cap 44 define an interior metal surface 58 of the container assembly 22 .
With the bottom cap 42 covering the first opening 52 , the end cap 44 covering the second opening 54 , and the valve assembly 24 supported by the end cap 44 , the aerosol dispensing system 20 defines the main chamber 28 .
Because the interior metal surface 58 of the container assembly 22 is metal and is thus susceptible to corrosion, the texture material concentrate is formulated to have anti-corrosion properties. The example texture material concentrate is generally formulated as follows.
GENERAL EXAMPLE OF TEXTURE MATERIAL CONCENTRATE
FIRST
SECOND
PREFERRED
PREFERRED
COMPONENT
RANGE
RANGE
solvent/carrier
30-60%
25-65%
resin/binder
4.5-5.5%
3-7%
fillers
40-60%
20-70%
additives
0.250-0.750%
0.000-1.000%
first anti-corrosion
0.5-2%
0.1-5.0%
material
second anti-corrosion
0.05-1%
0.025-2.0%
material
The texture material concentrate described in the table set forth above is combined in the container assembly 22 with the propellant material to obtain the contained material 34 . The preferred amount of propellant material used to form the example dispensing system 20 is approximately 12.5% of the texture material concentrate by weight and is preferably within a first preferred range of 10-15% and is in any event preferably within a second preferred range of 5-20%.
In the context of the example container assembly 22 comprising tin-plated steel components, the first and second anti-corrosion materials are included to promote passive corrosion behavior of the metal interior surface 58 of the container assembly 22 in contact with the texture material concentrate. Passive corrosion behavior occurs when the interaction between a metal structure and the environment forms a thin protective film on the surface of the metal structure. Passive corrosion produces essentially no corrosion of the metal structure and thus is very desirable.
In the example texture material concentrate, the first anti-corrosion material is Elfugin, which is an anionic, phosphate ester. Elfugin is a proprietary product sold by Clariant Paper Chemicals as an antistatic for application to paper products. In the general example described above, approximately 1.00% (±5%) of the first anti-corrosion material is preferably used. The second anti-corrosion material of the example texture material concentrate is sodium nitrite. In the general example described above, approximately 0.100% (±5%) or 0.250% (±5%) of the first anti-corrosion material is preferably used, depending upon the nature of the remaining components of the texture material concentrate and propellant.
The texture material concentrate is preferably formulated and combined with propellant material as follows. The first and second anti-corrosion materials are initially dissolved in the water. The remaining materials are then mixed with the water solution to obtain the texture material concentrate.
The bottom cap 42 is crimped onto the main member 40 to form a container subassembly 22 a . The valve assembly 24 is combined with the end cap 44 to form a cap subassembly 22 b . The texture material concentrate is placed within the container subassembly 22 a . The cap subassembly 22 b is crimped onto the container subassembly 22 a to form the container assembly 22 . The propellant material is then introduced into the container assembly 22 through the valve assembly 24 . The outlet assembly 26 is then engaged with the valve assembly to form the aerosol dispensing system 20 .
With the foregoing general understanding of the present invention, the details of several example formulations of the texture material concentrate and the construction and use of the example aerosol dispensing system 20 will now be described in further detail.
As described above, the present invention is of particular significance when applied to aerosol dispensing systems for dispensing texture material. Texture materials are sold in different forms depending upon such factors as dry time, ease of application, and the type of texture pattern desired. Set forth below are four tables containing formulations of example texture material concentrates.
The example contained materials incorporating the following texture material concentrates are preferably formed by first combining the first and second anti-corrosion materials with the water. The remaining materials are then mixed into the combination of the water and the anti-corrosion materials to form the texture material concentrates identified in the tables below. The resulting texture material concentrate is then mixed with the propellant material to form the contained material as generally described above.
First Example of Texture Material Concentrate
When sprayed onto a target surface as will be described in further detail below, the first example texture material concentrate forms what is commonly referred to as a “knockdown” spray texture pattern. A knockdown spray texture is formed by a bumpy, irregular texture pattern that is lightly worked with a tool after application to the target surface such that the tops of the bumps formed by the texture material are flattened.
FIRST
SECOND
PREFERRED
PREFERRED
COMPONENT
PREFERRED
RANGE
RANGE
solvent/carrier (water)
48.72%
43-53%
38-58%
first anti-corrosion
1.0%
0.5-2.0%
0.1-5.0%
material (Elfugin)
second anti-corrosion
0.25%
0.05-1.0%
0.025-2%
material (Sodium
Nitrite)
additive (biocide)
0.10%
0.05-0.50%
0.25-0.10%
Homax Wall Texture
50.93
46-56%
41-61%
In the foregoing example, the amounts of the first and second anti-corrosion materials are preferably held to tolerances of substantially ±5% of the amounts specified in the foregoing table.
The Homax Wall Texture ingredient is a proprietary mixture supplied to the Applicant by Hamilton Materials Northwest. Generally speaking, the Homax Wall Texture ingredient comprises a binder (starch), pigments like calcium carbonate, talc, mica, attapulgite clay, and possibly others. Additionally, this type of material typically comprises a biocide and defoamers.
The ratio of the first example contained material to propellant should be within a first range of approximately 7:1 to 15:1 and in any event should be within a second range of approximately to 20:1. To obtain the example contained material 34 , one part DME (propellant) is combined with 9.42 parts of the first example texture material described in the foregoing table.
Second Example of Texture Material Concentrate
When sprayed onto a target surface as will be described in further detail below, the second example texture material concentrate forms what is commonly referred to as an “orange peel” spray texture pattern. An orange peel spray texture comprises rounded, irregular bumps on the target surface that generally resemble the surface of an orange. By varying the parameters of the spray pattern, the size and depth of the bumps can be varied to obtain different aesthetic looks. The second example texture material concentrate further changes color while drying such that the color indicates when the texture material is sufficiently dry for the application of a top coat such as a coat of primer or paint.
FIRST
SECOND
PREFERRED
PREFERRED
COMPONENT
PREFERRED
RANGE
RANGE
solvent/carrier (water,
34.965%
30-40%
25-45%
proponal)
first anti-corrosion
1.000%
0.5-2.0%
0.1-5.0%
material (Elfugin)
second anti-corrosion
0.100%
0.05-1.0%
0.025-2%
material (Sodium
Nitrite)
additives (biocides,
0.530%
0.250-0.750%
0.000%-1.000%
defoamer, dispersant)
resin/binder (latex)
5.127%
4.100-6.100%
2.600-7.600%
filler (thickener, clay,
58.275%
53-63%
48-68%
talc, calcium
carbonate)
color change agent
0.003%
0.002-0.003%
0.001-0.010%
(Bromothymol Blue)
In the foregoing example, the amounts of the first and second anti-corrosion materials are preferably held to the following tolerances. The amount of the first anti-corrosion material used should be substantially within ±5% of the amount specified in the foregoing table. The amount of the first anti-corrosion material used should be substantially within +0% and −5% of the amount specified in the foregoing table.
The ratio of the second example contained material to propellant should be within a first range of approximately 7:1 to 15:1 and in any event should be within a second range of approximately 5:1 to 20:1. To obtain the example contained material 34 , one part DME (propellant) is combined with 9.42 parts of the first example texture material described in the foregoing table.
Third Example of Texture Material Concentrate
When sprayed onto a target surface as will be described in further detail below, the second example texture material concentrate forms what an orange peel spray texture pattern. As with the second example texture material concentrate described above, varying the parameters of the spray pattern varies the size and depth of the bumps forming the orange peel pattern to obtain different aesthetic looks.
FIRST
SECOND
PREFERRED
PREFERRED
COMPONENT
PREFERRED
RANGE
RANGE
solvent/carrier (water,
34.970%
30-40%
25-45%
propanol)
first anti-corrosion
1.000%
0.500-2.000%
0.100-5.000%
material (Elfugin)
second anti-corrosion
0.250%
0.050-1.000%
0.025-2.00%
material (Sodium
Nitrite)
Additives (biocides,
0.530%
0.250-0.750%
0.000%-1.000%
defoanner, dispersant)
resin/binder (latex)
5.127%
4.100-6.100%
2.600-7.600%
Filler (thickener, clay,
58.123%
53-63%
48-68%
talc, calcium
carbonate)
In the foregoing example, the amounts of the first and second anti-corrosion materials are preferably held to tolerances of substantially ±5% of the amounts specified in the foregoing table.
The ratio of the third example contained material to propellant should be within a first range of approximately 7:1 to 15:1 and in any event should be within a second range of approximately 5:1 to 20:1. To obtain the example contained material 34 , one part DME (propellant) is combined with 9.42 parts of the first example texture material described in the foregoing table.
Fourth Example of Texture Material Concentrate
When sprayed onto a target surface as will be described in further detail below, the fourth example texture material concentrate forms what is commonly referred to as a “popcorn” or “acoustic” spray texture pattern. A popcorn or acoustic spray texture pattern comprises visible particulates that are adhered to the target surface by binders in the base. The particulates somewhat resemble popcorn and provide acoustic dampening qualities that reduce echoing off of the target surface on which the popcorn or acoustic spray texture pattern is formed.
FIRST
SECOND
PREFERRED
PREFERRED
COMPONENT
PREFERRED
RANGE
RANGE
solvent/carrier (water)
57.05%
52-62%
47-67%
first anti-corrosion
1.02%
0.500-2.000%
0.100-5.000%
material (Elfugin)
second anti-corrosion
0.25%
0.050-1.000%
0.025-2.00%
material (Sodium
Nitrite)
Additives (biocide)
0.10%
0.050-0.500%
0.250-0.100%
Homax Wall Texture
40.76%
36-46%
31-51%
particulate (Melamine
0.82%
0.6-1.5%
0.25-5.0%
Foam)
In the foregoing example, the amounts of the first and second anti-corrosion materials are preferably held to tolerances of substantially ±5% of the amounts specified in the foregoing table.
The ratio of the fourth example contained material to propellant should be within a first range of approximately 12:1 to 15:1 and in any event should be within a second range of approximately 10:1 to 20:1. To obtain the example contained material 34 , one part DME (propellant) is combined with 13.29 parts of the fourth example texture material described in the foregoing table.
Referring again to FIG. 1 of the drawing, the details of construction and operation of the example dispensing system 20 will now be described in further detail.
The example valve assembly 24 comprises a valve housing 60 , a valve seat 62 , a valve member 64 , and a valve spring 66 . The end cap 44 supports the valve housing 60 and the valve seat 62 adjacent to the mounting opening 56 . The valve housing 60 supports the valve spring 66 such that the valve spring 66 biases the valve member 64 against the valve seat 62 in a normally closed position. An intake tube 68 extends from the valve housing 60 to the end of the main member 40 closed by the bottom cap 42 .
The outlet assembly 26 comprises an actuator member 70 , a resilient member 72 , and a clamp member 74 . The actuator member defines a stem portion 76 and a plurality of finger portions 78 . The stem portion 76 extends through the mounting opening 56 and engages the valve member 64 . The actuator member 70 supports the resilient member 72 such that the resilient member 72 is held within the finger portions 78 . The clamp member 74 engages the actuator member 70 such that displacement of the clamp member 74 relative to the actuator member 70 bends the finger portions 78 towards each other to deform the resilient member 72 .
A dispensing path 80 extends between an inlet opening 82 defined by the intake tube 68 and an outlet opening 84 defined by the resilient member 72 . Fluid is prevented from flowing along the dispensing path 80 when the valve assembly 24 is in the closed configuration as defined above. Fluid may flow along the dispensing path 80 when the valve assembly 24 is in the open configuration. The spray pattern of liquid flowing out of the main chamber 28 through the outlet opening 84 may be varied by deforming the resilient member 72 as described above.
More specifically, the valve spring 66 normally biases the valve member 64 against the valve seat 62 to close the dispensing path 80 . When the actuator member 70 is displaced towards the container assembly 22 , the valve member 64 is displaced away from the valve seat 62 against the force of the valve spring 66 to place the valve assembly 24 in its open configuration. In this open configuration, the example dispensing path 80 extends through a first passageway 90 defined by the intake tube 68 , a valve chamber 92 defined by the valve housing 60 , a gap 94 between valve member 64 and the valve seat 62 , a second passageway 96 defined by the actuator member 70 , and a fourth passageway 98 defined by the resilient member 72 .
Turning now to FIGS. 2A-2B of the drawing, depicted therein is an example of use of the example dispensing system 20 described above. The example dispensing system 20 is used to apply texture material to a wall member 120 defining a target surface portion 122 . In the case of a repair to the wall member 120 , existing spray texture material 124 typically surrounds the target surface portion 122 .
Initially, the dispensing system 20 is arranged such that the outlet opening 84 faces the target surface portion 122 . The actuator member 70 is then displaced to place the valve assembly 24 in its open configuration. The pressurized propellant material causes a portion of the contained material 34 to be dispensed from the container assembly 22 through the dispensing path 80 .
Because of the formulation of the contained material 34 and the geometry of the resilient member 72 , the contained material exits the container assembly 22 in a spray 130 comprising discrete droplets 132 . The droplets 132 are deposited onto the target surface 122 to form a texture coating 134 in an applied texture pattern. The texture coating 134 is initially wet but dries when exposed to air. In the case of a knockdown texture pattern, the texture coating 134 is worked to flatten the high points of the texture pattern when still wet. In the case of a color changing texture material, the texture coating 134 will be one color when wet and another color when dry.
By appropriately selecting the cross-sectional area of the outlet opening 84 , the applied texture pattern of the texture coating 134 can be formed such that the applied texture pattern substantially matches the existing pattern of the existing texture material 124 .
The popcorn or acoustic texture material described above is best dispensed using a second example dispensing system 220 as depicted in FIG. 3 . The aerosol dispensing system 220 comprises a container assembly 222 , a valve assembly 224 , and an outlet assembly 226 . The container assembly 222 and valve assembly 224 define a main chamber 228 .
The main chamber 228 contains a liquid material 230 and a vapor material 232 . The liquid material 230 comprises texture material and propellant material in liquid form. The vapor material 232 comprises propellant material in vapor form. The liquid material 230 comprises propellant material in liquid form and a texture material concentrate. The combination of the liquid material 230 and the vapor material 232 in the container assembly 222 will be referred to as the contained material 234 . FIG. 3 further illustrates that the contained material 234 comprises particulate material 238 as identified in the table above describing the example popcorn or acoustic texture material concentrate.
When the valve assembly 224 is in a closed configuration, the flow of fluid out of the main chamber 228 is substantially prevented. However, the vapor material 232 pressurizes the liquid material 230 within the main chamber 228 such that, when the valve assembly 224 is in an open configuration, the vapor material 232 forces the liquid material 230 out of the main chamber 228 .
As perhaps best shown in FIG. 3 , the example container assembly 222 comprises a main member 240 , a bottom cap 242 , and an end cap 244 formed of tin-plated steel. The tin-plated steel used to form the main member 240 , bottom cap 242 , and end cap 244 comprises a thin sheet of steel coated on one side by an even thinner layer (approximately 0.5 microns) of tin.
The main member 240 is a rectangular sheet that is rolled into a cylinder and welded along a seam 250 to define first and second end openings 252 and 254 . The bottom cap 242 is a shaped tin-plated steel member that is crimped onto the cylindrical main member 240 to seal the first end opening 252 . The end cap 244 is also a shaped tin-plated steel member defining a mounting opening 256 ; the end cap 244 is crimped onto the main member 240 such that fluid may not flow through the second opening 254 between the end cap 244 and the main member 240 . The main member 240 , bottom cap 242 , and end cap 244 define an interior metal surface 258 of the container assembly 222 .
With the bottom cap 242 covering the first opening 252 , the end cap 244 covering the second opening 254 , and the valve assembly 224 supported by the end cap 244 , the aerosol dispensing system 220 defines the main chamber 228 .
The bottom cap 242 is crimped onto the main member 240 to form a container subassembly 222 a . The valve assembly 224 is combined with the end cap 244 to form a cap subassembly 222 b . The texture material concentrate is placed within the container subassembly 222 a . The cap subassembly 222 b is crimped onto the container subassembly 222 a to form the container assembly 222 . The propellant material is then introduced into the container assembly 222 through the valve assembly 224 . The outlet assembly 226 is then engaged with the valve assembly to form the aerosol dispensing system 220 .
The example valve assembly 224 comprises a valve housing 260 , a valve seat 262 , and a stem member 264 . The valve seat 262 defines a deformable portion 266 . The end cap 244 supports the valve housing 260 and the valve seat 262 adjacent to the mounting opening 256 . The valve housing 260 supports the deformable portion 266 such that the deformable portion 266 biases the stem member 264 against the valve seat 262 in a normally closed position. An intake tube 268 extends from the valve housing 260 to the end of the main member 240 closed by the bottom cap 242 .
The outlet assembly 226 comprises an actuator member 270 . The actuator member 270 is threaded onto a connecting portion 272 of the stem member 264 . The stem member 264 further defines a valve portion 274 and a valve opening 276 . The stem member 264 extends through the valve seat 262 such that the valve seat 262 supports the stem member 264 within the mounting opening 256 . In particular, the stem member 264 extends through the mounting opening 256 such that the valve portion 274 is in contact with the valve seat 262 when the valve assembly 224 is in its closed configuration and not in contact with the valve seat 262 when the valve assembly 224 is in its opening configuration.
A dispensing path 280 extends between an inlet opening 282 defined by the intake tube 268 and an outlet opening 284 in the actuator 270 . Fluid is prevented from flowing along the dispensing path 280 when the valve assembly 224 is in the closed configuration as defined above. Fluid may flow along the dispensing path 280 when the valve assembly 224 is in the open configuration. The outlet member 270 is configured to define the outlet opening 284 such that the spray pattern of liquid flowing out of the main chamber 228 through the outlet opening 282 is substantially fan-shaped.
More specifically, the deformable portion 266 of the valve seat 262 frictionally engages the stem member 264 such that the deformable portion 266 normally biases the stem member 264 to cause the valve portion 274 to engage the valve seat 262 , thereby closing the dispensing path 280 . When the actuator member 270 is displaced towards the container assembly 222 , the stem member 264 is displaced, deforming the deformable portion 266 , such that the valve portion 274 disengages from the valve seat 262 against the force of the deformable portion 266 to place the valve assembly 224 in its open configuration. The deformable portion 266 may be replaced with an external or internal spring member that similarly biases the valve assembly 224 into the closed configuration.
In the open configuration, the example dispensing path 280 extends through a first passageway 290 defined by the intake tube 268 , a valve chamber 292 defined by the valve housing 260 , a gap 294 between stem member 264 and the valve seat 262 , the valve opening 276 , and an outlet passageway 296 defined by the actuator member 270 .
The actuator member 270 is configured to define a fan shaped outlet portion 298 of the outlet passageway 296 that forms a spray pattern appropriate for depositing the popcorn or acoustic texture material on the target surface in a desired texture pattern.
FIGS. 4A and 4B illustrate that the actuator member 270 is also configured such that the spray pattern may be directed upwards because popcorn or acoustic texture material is typically applied only to ceiling surfaces. In particular, FIG. 4A illustrates a wall member 320 defining a target surface portion 322 . In the case of a repair to the wall member 320 , existing spray texture material 324 typically surrounds the target surface portion 322 .
Initially, the dispensing system 20 is arranged such that the outlet portion 298 of the outlet passageway 296 faces the target surface portion 322 . The actuator member 270 is then displaced to place the valve assembly 224 in its open configuration. The pressurized propellant material causes a portion of the contained material 234 to be dispensed from the container assembly 222 through the dispensing path 280 .
The contained material exits the container assembly 22 in a spray 330 comprising discrete droplets 332 and the particulate material 238 . The droplets 332 are deposited onto the target surface 322 to form a texture coating 334 in an applied texture pattern. The particulate material 238 is bonded by the texture coating 234 to the target surface 322 . The texture coating 334 is initially wet but dries when exposed to air. The applied texture pattern of the texture coating 334 can be formed such that the applied texture pattern substantially matches the existing pattern of the existing texture material 324 .
The scope of the present invention should be determined by the claims appended hereto and not the foregoing detailed discussion of several examples of the present invention.
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A system for dispensing texture material in a desired spray pattern that substantially matches an existing texture pattern on a target surface comprises an aerosol dispenser, concentrate, and propellant material. The aerosol dispenser has an inner surface comprised at least in part of tin-plated steel. The concentrate comprises a solvent/carrier comprising water, a resin/binder, filler material, a first anti-corrosion material, and a second anti-corrosion material. The first anti-corrosion material is a phosphate ester and comprises approximately 0.5-2.0% by weight of the concentrate. The second anti-corrosion material is sodium nitrite and comprises approximately 0.05-1.00% by weight of the concentrate.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. provisional application No. 61/366,369 filed 21 Jul. 2010; entitled “Multi-configuration plant handle and holder”. The entire contents being hereby incorporated by reference and for which benefit of the priority date is claimed.
FIELD OF THE INVENTION
[0002] The present invention relates to a tool comprising a holder and handle for transporting plants in plastic pots and the like and, more particularly, to a multi configuration plant holder with means to multiple planters or porting such as at a nursery or loading a truck for easier transport.
BACKGROUND OF THE INVENTION
[0003] Plastic containers, also known as planters, in which ornamental plants are grown in a greenhouse have been known for some time in the prior art. These are also referred to as plant pots and are typically formed of stamped or molded plastic. Typically, the design of the container which holds the plant includes a rim being defined as a projection, folding, or jutting at or near the top of the container intended structurally as a stiffener to keep the container from collapsing or the container wall from ripping apart. The rim can be formed to project or extend outward from the container wall, or inward from the container wall.
[0004] When moving a multiple of such containers, such as loading a landscaping truck, transport truck such as a semi truck trailer, or at a nursery, typically each container has to be grabbed and moved individually, which is labor intensive and time consuming.
SUMMARY OF THE INVENTION
[0005] In accordance with the present invention, there is provided a tool for transporting potted plants with multiple ledges and having capability to interface with a pot having an inwardly directed rim, or a pot having an outwardly directed rim to pick up the plant and transport it from one location to another.
[0006] It is therefore an object of the invention to provide a tool for transporting potted plants having a face to stabilize the pots.
[0007] It is therefore an object of the invention to allow the transport of multiple pots associated with one handle.
[0008] It is another object of the invention to provide an active latch mechanism for holding multiple pots of either inwardly or outwardly directed rim orientations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent, detailed description, in which:
[0010] FIG. 1 depicts a front perspective view of a plant handle of one embodiment of the present invention;
[0011] FIGS. 2A , 2 B, depict perspective views showing part of a plant pot holder engaging with an outwardly directed plant container rim;
[0012] FIG. 2C , depicts a perspective view showing part of a plant pot holder engaging with an inwardly directed plant container rim;
[0013] FIG. 3 depicts a side view an alternate embodiment of a plant pot holder having two container holders being on opposite ends of an extension member;
[0014] FIGS. 4A and 4B depict a partial through section view of a third alternate embodiment of a plant container holder having two plant container holders hanging from each of two bifurcated extension members;
[0015] FIG. 5 depicts a front view of a handle and vertical member with a holding apparatus;
[0016] FIG. 6 depicts a rear view of a handle and vertical member with a holding apparatus;
[0017] FIG. 7 depicts a front perspective view of a forth alternate embodiment of a plant container holder comprising an active latch mechanism;
[0018] FIG. 8 depicts a rear perspective view of the embodiment of FIG. 7 ;
[0019] FIGS. 9A and 9B depict detail views of the pinching mechanism of the embodiment of FIG. 7 in release and gripping configurations respectively;
[0020] FIGS. 10 depicts rear perspective view of the embodiment of FIG. 7 holding a container having an inwardly directed pot rim and an outwardly directed pot rim.
DETAILED DESCRIPTION
[0021] A first embodiment, as shown in FIGS. 1-2 , show a tool and an example of use for the present invention for picking up a potted plant container or planter ( 22 ) by means of the planter rim ( 26 ). The apparatus, generally formed of light grade stamped steel and anodized or painted, comprising a handle member ( 10 ) being connected with a vertical extender ( 12 ), the vertical extender ( 12 ) can be adapted with a telescoping mechanism such as is common in the art and not shown, and having a holding apparatus ( 15 ) located distally from the handle ( 10 ).
[0022] The holding apparatus further comprising at least one ledge ( 16 ) for supporting an outwardly directed container rim ( 26 a ). The ledge can also be in connection with a face ( 14 ), with the face ( 14 ) being brought into contact with planter side wall ( 24 ) for stabilization of the planter ( 22 ). A typical operation comprising hooking the shelf ( 16 ) under the planter rim ( 26 ) and lifting.
[0023] A holding apparatus ( 15 ) further comprises a second ledge ( 18 ) or shoulder which in this case is a formed be bending or re-curving the bottom portion of the face ( 14 ). In this case the second ledge ( 18 ) forms a cleat or projection serving as a support or check to help keep the container ( 22 ) from sliding off the ledge ( 18 ).
[0024] As an alternate embodiment, the handle ( 12 ) as shown in FIG. 3 , multiple ledges ( 16 ) ( 18 ) can be formed from the same vertical extension ( 12 ) thus increasing carrying capacity.
[0025] In FIGS. 4A the vertical extension can be split, branched, or bifurcated into alternate extensions ( 12 a ) ( 12 b ) each associated with a separate holding apparatus ( 15 ) for holding multiple containers ( 22 ). In the current instance of FIG. 4 , the bifurcations are situated to allow multiple pots having either an inwardly directed rim ( 26 b ) extending into a planter wall ( 24 ) with an overhang ( 28 ) suited to receive a shoulder or ledge ( 18 ). In this instance the planter side wall ( 24 ) is allowed to hang below the holding apparatus ( 15 ) which can correct to a stable position via gravity.
[0026] A further configuration using the embodiment of FIG. 4 shown in 4 B is also suited to carrying a multiple of planters ( 22 ) having an outwardly directed rim ( 26 a ). In this example, the outwardly directed rim ( 26 a ) with an overhang ( 28 ) is better directed toward resting on ledge ( 16 ) with the planter side wall ( 24 ) resting on the face ( 14 ) of the multiple holding apparatus' ( 15 ).
[0027] FIGS. 5 and 6 illustrate an embodiment of the invention shown in FIG. 1 which is currently preferred for manufacturing purposes being able to be cut and stamped out of a single piece of sheet metal. As those skilled in the art will appreciate, the elements and functions previously described can be transferred applied to the embodiments shown therein.
[0028] In an alternate use of the embodiments of FIGS. 5 and 6 , two carriers can be used in parallel, preferably with the ledges ( 18 ) directed toward lifting a particularly large container (not shown) having a rim.
[0029] In yet another embodiment shown in FIGS. 7-10 , and active latch mechanism is provided for bringing a multiple of separate first ledge(s) ( 36 ) for supporting an outwardly directed container rim ( 26 a ) into proximity with a multiple of separate second ledge(s) ( 38 ) for supporting an inwardly directed container rim ( 26 b ). As can be seen from FIG. 10 this embodiment is capable of supporting multiple configurations simultaneously, supporting an outwardly directed rim ( 26 a ) and in inwardly directed rim ( 26 b ) planter ( 22 ) at the same time.
[0030] The mechanism comprises a latch handle ( 40 ) disposed near the handle ( 10 ), optionally with a spring ( 42 ) for retracting the mechanism to the open position. A shaft ( 46 ) is disposed to the interior of the vertical extender ( 12 ) with series of guide bushings ( 48 ) for guiding and centering. Near the bottom of the vertical extender ( 12 ) at least one, and preferably two beams ( 50 ) are rigidly attached. The beams ( 50 ) interface with at least one pivot ( 52 ) and pivot pin ( 62 ) having a face ( 56 ) extending downwardly and in connection with at least one inwardly directed ledge ( 38 ). The face ( 56 ) also in operational connection with a coupling member directed to a connection with the shaft ( 46 ) such that when the latch handle ( 40 ) is pulled toward the handle ( 10 ) the inward ledges are rotated inwardly toward at least one outwardly directed ledge ( 36 ). A spacer ( 60 ) is provided to hold a shelf ( 37 ) having at least one ledge ( 36 ) associated therewith.
CONCLUSION, RAMIFICATIONS, AND SCOPE
[0031] Although the present invention has been described in detail, those skilled in the art will understand that various changes, substitutions, and alterations herein may be made without departing from the spirit and scope of the invention in its broadest form. The invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.
[0032] Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequent appended claims.
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The present invention directed to an apparatus for holding at least one plant, and preferably multiple pots having plants, typically 5 to 8 inches in diameter, which may need to be transported such as at a nursery, or loaded onto a semitrailer for transport. The apparatus allows a user to easily pick up and hold the pots with little strain on the hands and wrists, and without needing to bend over to pick them up off the ground.
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FIELD OF THE INVENTION
[0001] The present invention generally relates to an apparatus and process for selective manufacturing of high aspect emitters and more particularly to an apparatus and process for manufacturing carbon nanotubes over a large surface area.
BACKGROUND OF THE INVENTION
[0002] Carbon is one of the most important known elements and can be combined with oxygen, hydrogen, nitrogen and the like. Carbon has four known unique crystalline structures including diamond, graphite, fullerene and carbon nanotubes. In particular, carbon nanotubes refer to a helical tubular structure grown with a single wall or multi-wall, and commonly referred to as single-walled nanotubes (SWNTs), or multi-walled nanotubes (MWNTs), respectively. These types of structures are obtained by rolling a sheet formed of a plurality of hexagons. The sheet is formed by combining each carbon atom thereof with three neighboring carbon atoms to form a helical tube. Carbon nanotubes typically have a diameter in the order of a fraction of a nanometer to a few hundred nanometers.
[0003] Existing methods for the production of carbon nanotubes, include arc-discharge and laser ablation techniques. Unfortunately, these methods typically yield bulk materials with tangled nanotubes. Recently, reported by J. Kong, A. M. Cassell, and H Dai, in Chem. Phys. Lett. 292, 567 (1988) and J. Hafner, M. Bronikowski, B. Azamian, P. Nikoleav, D. Colbert, K. Smith, and R. Smalley, in Chem. Phys Lett. 296, 195 (1998) was the formation of high quality individual single-walled carbon nanotubes (SWNTs) demonstrated via thermal chemical vapor deposition (CVD) approach, using Fe/Mo or Fe nanoparticles as a catalyst. The CVD process has allowed selective growth of individual SWNTs, and simplified the process for making SWNT based devices. The selection of the desired production process should consider carbon nanotube purity, growth uniformity, and structural control. Arc-discharge and laser techniques do not provide the high purity and limited defectivity that may be obtained by the CVD process. The arc-discharge and laser ablation techniques are not direct growth methods, but require purification, placement and post treatment of the grown carbon nanotube. In contrast to the conventional plasma-enhanced CVD (PECVD) methode, a known hot filament chemical vapor deposition (HF-CVD) technique allows one to prepare high quality carbon nanotubes without damage to the carbon nanotubes structure. Because of the lack of a need for plasma generation, a HF-CVD system apparatus is usually of simple design and low cost. As compared to thermal CVD, HF-CVD demonstrates high carbon nanotube growth rate, high gas utilization efficiency and good process stabilization over large area substrate at relatively low temperature suitable with the glass substrate transformation point (typically between 480° C. to 620° C.).
[0004] The hot filaments array is the thermal activation source of the HF-CVD apparatus. Its main functions are to heat the process gas, to dissociate the hydrocarbon precursors into reactive species and fragment molecular hydrogen into active atomic Hydrogen. These active species then diffuse to the heated substrate (typically a glass panel) where catalytic carbon nanotube growth takes place. In prior art HF-CVD systems, the heated surface of thin metal filaments are converted info carbide, or carburizes, in the presence of hydrocarbon gases. The formation of carbides is known to promote filament fragility and consequently filament lifetime issues. Furthermore, the filament brittleness outcome is intensified by the hydrogen that is present in the process gas mixture. Generally the diameter of hot filaments used in conventional HF-CVD processes is small (i.e. on the order of few hundred micro meters to about 1 milimeter) and the filaments are physically supported at their extremities by a rigid grid frame, so that the filaments are stretched in a horizontal direction. During filament resistive heating, due to thermal re-crystallization, these small diameter filaments tend to expand in the linear direction. As a result, the hot and thin filaments tend to physically sag toward the substrate due to gravity; thereby producing deformed filaments and uneven filament grid gap over the planar substrate surface. As the substrate to filament distance is thus distorted by this filament sagging, the non regular shape of the hot filament grid promotes localized temperature variation and consequently growth non uniformity over large substrate area.
[0005] Field emission devices that generate electron beams from electron emitters such as carbon nanotubes at an anode plate for creating an image or text on a display screen are well known in the art. The use of a carbon nanotube as an electron emitter has reduced the cost of vacuum devices, including the cost of a field emission display. The reduction in cost of the field emission display has been obtained with the carbon nanotube replacing other electron emitters (e.g., a Spindt tip), which generally have higher fabrication costs as compared to a carbon nanotube based electron emitter. Each of the electron beams are received at a spot on the anode plate, referred to as a pixel on the display screen. The display screen may be small, or very large such as for computers, big screen televisions, or larger devices. However, integration of carbon nanotube field emitters over very large display requires one to address many fabrication and process quality issues that have proven difficult to overcome. These issues include uneven heating of the substrate, limited temperature range of the glass substrate during carbon nanotube growth, poor control of thermal gas dissociation, contamination of the carbon nanotube, and inconsistent process reliability due to the drift of the filament resistivity at process temperature.
[0006] As mentioned above, known manufacturing methods of carbon nanotube display devices require a high temperature. These methods typically require a substrate heater and a gas dissociation source made of an array that encompasses a plurality of resistively heated metallic filaments overlying the nanotube growth region. However, for the HF-CVD of carbon nanotubes over larger display panels, equal distribution of heat required for uniform carbon nanotube growth has not been obtained due to the metallic heater filament bending, or sagging, towards the substrate due to gravity. This creates hotter localized areas where the metallic heater filament sags. The resistively heated metallic filament also provides for thermal dissociation of the process gases; however, the variation of the electrical properties of the metallic filament due to resistance drift leads to variation in the gas dissociation, radical species, and consequently in non uniformity and non reproducibility of the carbon nanotube growth process.
[0007] Accordingly, it is desirable to provide an apparatus for manufacturing large scale carbon nanotube display devices. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
BRIEF SUMMARY OF THE INVENTION
[0008] An apparatus is provided for growing high aspect ratio emitters on a substrate. The apparatus comprises a housing defining a chamber, and a substrate holder attached to the housing and positioned within the chamber for holding a substrate having a surface for growing the high aspect ratio emitters thereon. A heating element is positioned near the substrate and being at least one material selected from the group consisting of carbon, conductive cermets, and conductive ceramics. The housing defines an opening into the chamber for receiving a gas into the chamber for forming the high aspect ratio emitters.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
[0010] FIG. 1 is an isometric schematic of a growth chamber in accordance with an embodiment of the present invention;
[0011] FIG. 2 is a side schematic view of the growth chamber of FIG. 1 ;
[0012] FIG. 3 is an isometric view of a heater element shown in FIG. 1 ;
[0013] FIG. 4 is a schematic showing the spacing of the heater element shown in FIG. 3 ;
[0014] FIG. 5 is an isometric view of another embodiment of the heater element;
[0015] FIG. 6 is an isometric view of yet another embodiment of the heater element;
[0016] FIG. 7 is a schematic side view of the substrate and heater element showing direct radiation from the heater element;
[0017] FIG. 8 is a schematic side view of another embodiment of the substrate and heater element showing direct radiation from the heater element.
[0018] FIG. 9 is a schematic side view of the substrate showing electron movement during growth;
[0019] FIG. 10 is a schematic side view of a first biasing scheme in accordance with an embodiment of the present invention;
[0020] FIG. 11 is a schematic side view of a second biasing scheme in accordance with an embodiment of the present invention; and
[0021] FIG. 12 is a schematic side view of a third biasing scheme in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.
[0023] A hot filament chemical vapor deposition apparatus is described in detail below that comprises a plurality of heated filaments having a high melting temperature, a non-metal, electric conductiveness, chemical and thermal inertness, and stability to the process gas (e.g., hydrogen and a hydrocarbon gas mixture, or other reactive gases such as O 2 , N 2 , and NH 3 ) used for carbon nanotube growth.
[0024] Referring to FIGS. 1 and 2 , a simplified schematic view of a growth chamber includes a substrate holder 11 attached to a housing 10 . The growth chamber 20 may be used to grow high aspect ratio emitters 26 , e.g., carbon nanotubes, on the substrate. A substrate heater 12 is generally positioned below the substrate holder 11 for heating a substrate 13 which is positioned on the substrate holder 11 during growth. Although the substrate heater 12 is typical in most applications (such as the fabrication of integrated circuits), applications are envisioned where it is not required and can be replaced by a water cooled substrate holder (e.g., growth of carbon nanotubes on a low melting point substrate of less than 150° C. such as polymer or plastic). An optional gas showerhead 14 receives reactive feed gas via the gas inlet 15 and is positioned above the hot filament array 17 for distributing gas evenly over the substrate 13 . The shower head 14 may not be necessary if the gas transmitted into the chamber 20 is sufficiently pressurized. A substrate for a large glass display is heated by placing it above a substrate heater 12 , which typically comprises electrical resistance wire embedded in and electrically insulated from the substrate holder 11 which provides radiative and conductive heat to the substrate holder 11 (a graphite material is the preferred embodiment use for substrate heater to minimize the reactive interaction of the substrate heater element with the reactive gases process). Because the substrate holder 11 has a large thermal mass (compared to the substrate 13 ), its temperature varies very slowly. This permits better temperature control and uniformity for a large area substrate. The substrate 13 (e.g., glass panels) is placed on the substrate holder 12 , and is heated by radiation, conduction, and/or convection. As compared to direct heating by the hot filaments, one of the key advantages of heating with the use of an additional substrate heater is that narrow glass temperature uniformity of the glass panel can be achieved while the water-cooled HF-CVD reactor walls are kept at room temperature. The substrate heater 12 allows better control for adjusting the substrate 13 temperature with the glass substrate in close contact to the substrate heater 12 , the temperatures of the two elements are quite close at all times. This offers a practical way to monitor the glass panel average temperature using thermocouples (not shown) embedded in the substrate holder.
[0025] In the growth of nanotubes 26 , a catalyst (not shown) typically is deposited on the substrate 13 prior to growing the nanotubes 26 . The catalyst may comprise Nickel, or any other catalyst made of transition metal known in the industry. Finally to cool the glass panel at the end of the CNT growth process, the glass panel can be removed from the substrate heater and transferred to another load lock chamber (not shown) to speed up the reduction of temperature.
[0026] In accordance with the preferred embodiment of the present invention (also referring to FIG. 3 ), the heating element 16 is a gas dissociation source comprising a plurality of equidistant filaments 17 positioned parallel above the substrate 13 . The heating element 16 is coupled between two parallel supports 18 made of conductive material (i.e. metal, graphite, conductive ceramic) and electrically insulated from each other. Each support 18 is connected to a DC voltage source or a low frequency AC voltage source 21 which supply current to resistively heat the filaments 17 . When the filaments 17 are heated, the substrate 13 temperature starts to increase up to a certain temperature. This upper limit temperature reached by the substrate 13 is the result of both the amount of heat transfer from the filament 17 and the substrate heater 12 , and the heat conductance between the substrate 13 and the substrate holder 11 . Therefore, to improve the controllability of the substrate temperature, both the reduction of the heat transfer from the filaments 17 and the increase of the heat conductance are required. A solution to improve the controllability of substrate temperature is to use a carbon mesh-shaped array 41 ( FIG. 4 ) instead of the filaments array 17 ( FIG. 3 ). This mesh shaped array permits a reduction in the amount of heat transfer from the filament and to reduce the difference in temperature between the substrate temperature and the temperature of the substrate holder 11 . A bias is provided between the substrate holder 11 and the heating element 16 . The parallel filament array 17 is the preferred embodiment for uniform carbon nanotube 26 growth on large substrate area. For a given substrate 13 area and optimized substrate-filament distance, the filament diameter, the minimum filament length, the number of parallel filaments, and the separation between them are considered when designing for efficiency.
[0027] The heating element 16 comprises an electrically conducting, high melting temperature material consisting of at least one of carbon (including graphite), conductive cermet, and a conductive ceramics (e.g., B, Si, Ta, Hf, Zr, that form a carbide and/or nitride). According to the preferred embodiment, the filaments 17 are made of straight graphite wires 0.25 mm to 0.5 mm or larger in diameter, and heated by a DC or low frequency AC current. The filaments 17 are arranged to form an array of parallel linear filaments 17 that are parallel to the plane of the substrate 13 . They are electrically connected in parallel, each having a length varying from few cm to over 50 cm. must be positioned close enough to the substrate 13 wherein the radiation pattern 61 of each overlap to provide a uniform distribution of heat to the substrate 13 . For a given filament diameter, the number of filaments 17 and the distance D between the filaments 17 is determined with respect to an optimum distance H between the filaments 17 and the substrate 13 (see FIG. 4 ). Generally, to obtain carbon nanotube 26 growth, uniformity apart from ensuring uniform substrate temperature, the filament array 17 is designed in such a way that the distance between the filaments 17 is less than half the distance between the filaments 17 and the substrate 13 .
[0028] Referring again to FIG. 1 , a DC or low frequency AC current source 21 supplies current through connectors 22 and 23 to the supports 18 and thus to the heating element 16 for generating a radiant heat. A resistor 24 is coupled between the gas distribution element 14 and the connector 23 for biasing the gas distribution element 14 so electrons from the heating element 16 are directed away from the gas distribution element 14 . A DC voltage source 25 is coupled between the substrate holder 11 and the low frequency AC current source 21 , preferably at the center point as shown, for attracting electrons from the heating element 16 towards the substrate 13 .
[0029] Referring to FIG. 5 , a second embodiment of the graphite heating element 16 comprises a mesh 41 , positioned between the supports 18 . And a third embodiment of the heating element 16 , as shown in FIG. 6 , comprises a hollow rod acting both as an heating source and a gas distributor 51 . The hollow rod 51 comprises an input 52 for receiving process gas and a plurality of orifices 53 for distributing the gas over the substrate 13 as indicated by the arrows 54 . As with the first embodiment, the mesh 41 and hollow rod 51 comprise an electrically conducting, high melting temperature material consisting of at least one of carbon (including graphite), conductive cermet, and a conductive ceramics (e.g., B, Si, Ta, Hf, Zr, that form a carbide and/or nitride).
[0030] Referring to FIGS. 7 and 8 , the filaments 17 radiation is exemplified as two components: one for the direct radiation from the filament 17 and another component for the indirect reflected radiation from the filament, respectively. As expected, approximately half of the radiation power is from direct radiation. The other half is from indirect radiation which is either partially reflected or absorbed by the gas distributor 14 located above the filaments 17 . The purpose of the reflector-like gas distributor 14 shape, represented in FIG. 8 , is to reflect the radiation from the filament as much as possible downwards towards the substrate 13 and improved radiation uniformity distribution by the showerhead 14 surface facing each filament being shaped more of less like an ellipse. The filament 17 is perfectly centered with respect to this elliptic shape and this elliptic surface is very smooth and preferably coated with highly reflective material.
[0031] The substrate 13 is heated by radiation from the heating element 16 and by hydrogen atom recombination. In known CVD processes, a mixture of CH 4 in H 2 flows through the chamber, and a hot filament or plasma is used to dissociate the gas precursors into CH y and H radicals, where y=4, 3, 2, 1, 0. In the HF-CVD method of the preferred embodiment, CH y and H are mainly generated at the surface of the hot filament 17 . These species are then transported by diffusion and convection to the substrate. Depending on the catalyst, the carbon nanotube 26 formation consumes the CH y radicals causing their concentrations to decline to the level at which catalytic particle activation and consequently the carbon nanotube growth is reduced or stopped.
[0032] One of the primary functions of the heating element 16 temperature is to set the upper limit of the gas process temperature. The heating element 16 temperature is large enough it produces a thermionic electron emission current whose intensity can be controlled by a positive bias voltage applied to the substrate 13 . The electrons interact with the process gases, because there are high densities at the surface of the heated heating element 16 . The reaction with CH 4 is well known i.e. e-+CH 4 ->CH+3+H+2e. even without any acceleration voltage the electrons have an energy of 5 eV. Hence applying a bias increase or decrease the electron energy as shown in FIG. 9 . In the absence of a substrate 13 bias, carbon nanotube 26 growth rates are slow. Thus, this thermionic electrons emission enhances the gas molecular fragmentation reactions which form the precursors necessary for the carbon nanotube 26 growth.
[0033] The heating element 16 provides several advantages over known systems. First, the non-metalic material used is rigid and does not sag like known metallic filaments. During heating, the metallic filament expansion is a major cause of non-uniform carbon nanotube 26 growth. The known metallic filaments expand when heated to the operating temperatures ranging from 1500° C. to greater than 3000° C. The filament sagging induces hot spots on the glass substrate (where it sags) and relatively cold spots (where it doesn't sag). Therefore, by not sagging, the heating element 16 of the present invention provides a uniform distribution of heat over the substrate 13 . The use of carbide or nitride, which has no liquid state, avoids transformation of material characteristics due to temperature change. Secondly, during the carbon nanotube growth, the metallic filaments of the known art typically react with the hydrocarbon gases to form carbide. This carbide formation leads to more thermal-induced stress (more sagging), strong intrinsic resistivity variation and change in the work function. Therefore, one object of this invention is to provide an apparatus where the heated gas dissociation source is made of a non-metallic heating element 16 that is inert to the process reactive gases.
[0034] Another advantage of the heating element 16 is an enhanced disassociation of the gas used in the growth process. In accordance with the process of the present invention in the growth of the high aspect emitters 26 , e.g., carbon nanotubes, a gas comprising CH 4 and H is applied evenly across the heating element 16 at a temperature preferrably of 1500° C. to greater than 3000° C. and a pressure in the range of 10-100 Torr, cracking the gas, thereby forming various hydrocarbon radicals and hydrogen suitable for the growth process. Referring to FIG. 9 , electrons coming out of the hot filaments 17 pass through the vacuum region between the heating element 16 and substrate 13 and hit the substrate, causing a current flow to ground. The heating element 16 , being negatively biased to the substrate 13 , causes the electrons to accelerate and reach the substrate 13 .
[0035] One of the key parameters in a HFCVD process is the production rate of atomic hydrogen at the heating element 16 . Atomic hydrogen plays a key role in the growth of carbon nanotubes 26 for two reasons: it is crucial in the generation of the hydrocarbon radicals, and it plays an important role in the fragmentation and oxide reduction of catalyst particle as well as in the growth of carbon nanotubes 26 . The difference in the characteristics of the synthesized carbon nanotubes 26 in accordance with the present invention is caused by the difference in radical species desorbed from hot surfaces at different heating element 16 temperatures. Radicals generated by the thermal decomposition of hydrocarbon gases (i.e. CH 4 ) at the hot surface react with gas phase species to produce the precursor molecules for carbon nanotube 26 growth. Control of the gas species desorbed from the heating element 16 is essential for managing of chemical kinetics for the catalytic carbon nanotube 26 growth by HF-CVD processes.
[0036] Referring to FIG. 9 , electrons are also responsible for the generation of the reactive species which will form the carbon nanotubes 26 upon impact dissociation of the gas molecules, a relevant parameter in the deposition process is the electron current flowing to the substrate 13 in the region between the heating element 16 and the substrate holder 11 . If the electric field in this region is sufficient to accelerate the heating element 16 free electrons to energies large enough to produce ionization of the gas molecules, the current collected by the substrate 13 is composed of electrons thermionically generated by the heating element 16 and electrons detached from the gas molecules due to ionization.
[0037] As compared to previous art HF-CVD techniques utilizing a metal filament, the electrical resistivity of carbon, a conductive cermet, and conductive ceramics, e.g., B, Si, Ta, Hf, Zr, that form a carbide and/or nitride is greater than the resistivity of pure metal. Thus, the heated heating element 16 can be constructed with a larger diameter. This favors the mechanical strength and rigidity of the heating element 16 . It minimizes even more the sagging effect, and improves the lifetime of the heating element 16 .
[0038] Because graphite heating element 16 do not form carbide (do not carburize), do not melt, and have an extremely high solid to gas phase transition temperature (about 4000° C. for graphite), a broader range of temperatures can be used during the carbon nanotube 26 growth process and contamination of the substrate and subsequently of the carbon nanotubes 26 is less likely to occur. The non-carburization of the heating element 16 is an advantage leading to a reproducible, controllable and uniform carbon nanotube 26 HF-CVD process.
[0039] All processes for the carbon nanotube 26 growth by conventional chemical vapor deposition involve the generation of the active species, the transport of the active species to catalyst, and activation of the growth species at the catalyst surface. However, to achieve a high growth rate, more power into the growth system is required to generate more active radicals and deliver them to the surface as fast as possible. A hot heating element 16 is known to be a perfect radiation heat source and a saturated source of electrons as seen in FIG. 9 . Thus, the adjunction of negative bias voltage applied to the hot heating element 16 permits the extraction and acceleration of these saturated hot electrons. At a given heating element 16 temperature, electron flow is extracted and controlled by a positive bias 25 applied to the substrate 13 . At given pressure, the biased substrate 13 is sufficient to accelerate electrons to energies suitable for fragmentation and excitation of the process gas. Therefore, collision with accelerated electron becomes mainly responsible for gas dissociation and excitation, and permits to operate at lower heating element 16 temperature. This combination of electrical potential and HF-CVD favors a better thermal management between the substrate heater and the heating element 16 . It improves the temperature control and permits carbon nanotube 26 growth at lower temperatures. With respect to the heating element 16 temperature and the system pressure (mean free path of the electron) the extraction voltage can be tuned for optimizing the gas phase reaction and the carbon nanotube 26 growth rate. The reason HF-CVD methods can lead to high growth rates are its high working pressure as compared to plasma enhanced CVD (PECVD). In high pressure biased HFCVD, the mean free path for collisions between electrons and molecules is small and thus any excess energy absorbed by the electrons from the applied electric field is quickly redistributed to the larger gas molecules by electron and molecular collisions. Consequently the spacing between the hot heating element 16 and the substrate can be increased for better thermal management and better distribution uniformity of the carbon nanotubes 26 . The experimental results show that this combination has advantages in terms of growth rate of carbon nanotube 26 quality for field emission application, over conventional HF-CVD. Therefore, the temperature of the gas molecules and electrons equilibrate at a relatively high temperature. Generation of atomic hydrogen and molecular hydrocarbon radicals occur as the result of both high energy molecular and electron collisions. In addition, the convection and diffusion velocities are increased in this high gas temperature gradient region. Thus, the absolute concentration of atomic hydrogen and molecular radicals is increased in high pressure biased HF-CVD. This contributes to a high carbon nanotube 26 growth rate. In summary, the non-metallic material used for heating element 16 in the HF-CVD process in accordance with the present invention leads to filament 17 extended life time, reduced filament 17 evaporation, and reduced nanotube 26 and substrate 13 contamination, controlled stabilized carbon flux to the substrate 13 during carbon nanotube 26 growth, and reliable and reproducible process from run to run.
[0040] Referring to FIG. 10 , an intermediate electrode 81 having an alternating current or radio frequency signal 82 applied provides a means for imparting additional energy to the process to create additional disassociation of the gas with the subsequent creation of additional species. During the catalyst induction/or carbon nanotube 26 growth step, the HF CVD reactor could run in this hybrid configuration. First, an additional AC or RF bias voltage 82 is applied between the hot heating element 16 and a plasma-grid placed underneath in the space between the heating element 16 and the substrate 13 . Second, a DC or low frequency RF substrate bias 25 could be applied to the substrate 13 to impact its surface with electrons. The function of the AC or RF bias 82 is to generate conventional plasma between the heating element 16 and the intermediate grid 81 leading to gas process dissociation and activation enhancement in this filament-grid confined region. The function of the grid 81 and the DC bias 25 is to shield the effect of ion bombardment at the substrate 13 and to accelerate only the electrons and the reactive hydrocarbon radicals towards the substrate 13 . Independent control of the different voltages with respect to the heating element 16 temperature, permits a fine tuning of the gas dissociation and electrons flowing to the substrate 13 . In this hybrid mode arrangement, the HF-CVD reactor exhibits higher process flexibility and capability.
[0041] Referring to FIG. 11 , an alternating current or radio frequency signal is applied to the heating element 16 and gas showerhead 14 , or in absence of showerhead to a thermal shield located over the heating element 16 . This arrangement results in additional energy imparted to the precursor gas, causing more efficient disassociation of the gas species. A DC substrate bias is applied to the substrate 13 to extract the saturated electron from the heating element 16 and increase the electron impact of its surface. Both hybrid configuration of HF-CVD allow for independently control of the catalyst induction and carbon nanotube growth stages, to carry out homogenous and uniform carbon nonotube 26 growth, to enhance the substrate 13 bombardment by electrons and shift down the temperature to the range where only selective carbon nanotube 26 growth is still the dominant process. These hybrid HF CVD techniques in comparison to the standard HF CVD technique show significant advantage to control the carbon nanotube 26 growth kinetics over a broader range of substrate 13 materials.
[0042] Referring to FIG. 12 , yet another embodiment comprises the gas distribution element 14 including openings 101 formed as slits parallel and below the filaments 17 that are positioned within the gas distribution element 14 for distributing the gas as indicated by the arrows 104 . The slits ( 101 ) are biased with an additional power supply 102 which allows the element to act as a control grid. The addition of this control grid allows the control of the electron flux from the aperture of the slit, while at the same time the material of the gas distributor 14 surrounding the filament 17 rods reduces infrared radiation from the filaments 17 , and serves as a gas concentrator to allow more efficient disassociation of the gas species. Controlling the electron flux can be important in the growth and nucleation of certain types of nanotubes and nanowires and can also assist in the nucleation of the nanoparticle.
[0043] The heating element 16 consisting of at least one of carbon (including graphite), conductive cermet, and a conductive ceramics (e.g., B, Si, Ta, Hf. Zr, that form a carbide and/or nitride), provides a more uniform distance to substrate 13 with an homogeneous radiation heating of the substrate 13 , and a controlled electro-thermal dissociation of the gases which leads to uniform growth of the high aspect ratio emitters 26 over a large area. The high melting temperature of these materials results in a broader range of temperature during emitter growth, a substantial increase in the electron current density flowing out of the heating element 16 , and consequently an increase of thermal gas dissociation and the formation of atomic hydrogen. Furthermore, the use of these materials for the heating element 16 eliminates the risk of catalyst and emitter contamination due to evaporation of heating element 16 material (hydrogen embrittlement), provides a constant resistance value of the heating element 16 due to chemical inertness and absence of carbide formation with the heating element 16 , and consequently a stable emission current for better gas dissociation reaction from one growth to the next, and longer heating element lifetime. An important consequence of the use of these materials for the heating element 16 is the increase of atomic hydrogen production rate at the heating element 16 . The generation of larger flux of electron modulated by an electric field permits more controlled gas dissociation and temperature uniformity, as well as a more mechanically robust and stable thermionic source. These improvements result in a practical reproducible production process and equipment for low temperature growth on a large area substrate.
Process Example
[0044] During a batch HF-CVD process, the HF-CVD reactor is evacuated at a base vacuum pressure in the low 10E-6 Torr by using primary and a turbo-molecular pump package. Once the base pressure in the reactor is reached, the heating element 16 , comprising filaments 17 for example, is heated at a temperature preferrably greater than 1500 degree C. The substrate heater 12 is also switched on and allows the substrate 13 temperature to be controlled independently from the filament 17 temperature.
[0045] When the substrate 13 reaches a temperature of 350 degree C., molecular high purity hydrogen gas is flowed through a mass flow controller (MFC—not shown) over the hot filament 17 . The pressure in the reactor 10 is controlled by adjusting the throttle valve between the deposition chamber (housing 10 ) and the vacuum pump (not shown), as well as by the MFC. The MFC provides a way to introduce fixed flow rates of process gases into the HF-CVD reactor. The first step of the carbon nanotube growth consists in the catalyst particle fragmentation and reduction in hydrogen at a partial pressure of 1E-1 Torr. The pressure in the HF CVD system is monitored by a MKS pressure manometer (not shown).
[0046] When the substrate 13 temperature reaches 500° C., a hydrocarbon gas (e.g., CH 4 ) is flowed and mixed to the hydrogen gas in very specific hydrogen to hydrocarbon gases ratio, and the power input into the filament array 17 is increased. At the same time the pressure in the reactor is also increased to 10 Torr and then the incubation phase of the catalyst particles (nucleation of carbon nanotubes) is initiated for the time necessary, typically a few minutes, to reach the carbon nanotube growth temperature of 550 degree C.
[0047] Once at temperature, the carbon nanotube 26 growth step is started by switching on the DC and/or RF power supply 21 biasing the filaments 17 and the substrate holder 11 . Depending on the previous process condition (i.e. pressure, gases ratio, bias current flowing to the substrate) and the carbon nanotubes 26 desired (e.g., length, diameter, distribution, density, etc.), the duration of the growth may vary from 2 minutes to 10 minutes.
[0048] At the end of the growth, the filament array 17 , the substrate heater 12 , as well as the bias voltage 21 are turned off, the process gas flow is switched off and the substrate 13 is cooled down to room temperature. The long cooling down step in batch HF-CVD-reactor 20 can significantly be reduced by flowing a high pressure of neutral gas (e.g., He, Ar) that increases the thermal conduction exchange with the cold wall of the reactor.
[0049] While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, 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 of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, 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 of the invention as set forth in the appended claims.
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An apparatus is provided for growing high aspect ratio emitters ( 26 ) on a substrate ( 13 ). The apparatus comprises a housing ( 10 ) defining a chamber and includes a substrate holder ( 12 ) attached to the housing and positioned within the chamber for holding a substrate having a surface for growing the high aspect ratio emitters ( 26 ) thereon. A heating element ( 17 ) is positioned near the substrate and being at least one material selected from the group consisting of carbon, conductive cermets, and conductive ceramics. The housing defines an opening ( 15 ) into the chamber for receiving a gas into the chamber for forming the high aspect ratio emitters ( 26 ).
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FIELD OF THE INVENTION
The invention relates to a dust filter bag made of a fiber layer laminated together with a paper layer. A wide variety of demands are placed on such filter bags. One goal is to obtain a high filtration effect, i.e. a high level of retention. For this, the filter pores must be sufficiently small. At the same time, however, the filter pores of the dust filter bag must not clog up, so that a high level of suction or blowing performance, for example of a vacuum cleaner, is maintained, and there is no need to replace the dust filter bag for that reason alone before a specific fill level is reached.
In addition, the dust filter bag must exhibit sufficient mechanical strength so as not to tear or burst while being installed or when full. Appropriate strength is also necessary for manufacturing the bag by way of multiple folding operations.
BACKGROUND OF THE INVENTION
Dust filter bags that are made of a porous nonwoven fabric and a filter paper are known from European Patent 0 635 297 A1, and are processed into double-layer dust filter bags. A melt-blown fine fiber batt, which covers the inner side of the dust filter bag and reinforces the dust filter bag, can be used as the nonwoven fabric. However, the reinforcing effect presented by this approach is not satisfactory.
Further dust filter bags are known from European Patent 0 338 479 B1. The dust filter bag described therein comprises a filter-paper outer ply and an internally located nonwoven fabric. The nonwoven fabric is configured as a fine-fiber nonwoven fabric and is also arranged on the inflow side. The fine fibers of the fine-fiber nonwoven fabric can be applied in the thermoplastic state directly onto the filter paper and joined to it. The fine-fiber nonwoven fabric can be joined to a support element which is also made of nonwoven fabric. To produce the semifinished bag, a tube is formed from the laminate and is closed with a longitudinal seam. Pieces of finite length are then cut off from the endless tube on a bottom-seam drum. An air pulse is used to open the tube ends on one side in order to ensure the formation of tabs which are turned over and adhesively bonded to one another. However, because the two internally located nonwoven fiber plies can easily weld to one another during the cutting process, they can no longer reliably be opened with the air pulse.
German Patent 196 06 718 A1 furthermore discloses a multiple-ply filter pouch that has a first inner ply made of a fine-fiber nonwoven fabric, a second outer ply made of a plastic matted-fiber material, and a third ply, arranged before the first ply in the flow direction, made of a paper material. This creates the filtration effectiveness of the ply made of paper material, since with an external arrangement, the actual filtering effect occurs first.
A further disadvantage of the known dust filter pouches is the fact that when water or other fluid is drawn in along with the air being cleaned, the filter paper ply softens and its strength is impaired, creating the risk of tearing and contamination of the environment during vacuum cleaning or when the dust filter bag is removed. The filtering effect in terms of ultrafine particles is less than satisfactory.
SUMMARY OF THE INVENTION
The present invention provides a bag in which the fiber layer contains melted polymer regions and, because of the polymer regions, is additionally consolidated within itself and joined to the paper layer. The polymer regions have a welded surface area of 0.5 to 10% of the surface. Consequently, loss of strength in the paper layer no longer results in damage to the dust filter bag. Even in the event of tearing in the paper layer in the interior of the dust filter bag, emergence of dust particles from the interior of the dust filter bag is prevented by the externally located fiber layer. The presence of a welded area of the polymer regions equaling 0.5 to 10% of the surface area, preferably 1 to 3%, results in sufficient laminate strength with a tolerable increase in the pressure differential.
Despite the possibility for water uptake, the use of the paper layer, which is advantageous for the creation of folds, can be retained. The reason is that only with a paper layer, as opposed to a pure fiber layer made of polymer fibers, does the dust filter bag become foldable. Foldability can be improved by way of a denser pattern of melted polymer regions in the region of the edges.
A minimum extension of the polymer regions of 1 mm in terms of length and/or width, and optionally also diameter, has proven particularly suitable for creating sufficient adhesion of the fiber structure on the paper layer.
The polymer regions can be penetrated at least partially into the paper layer, in which they bring about an additional and semi-hard consolidation of the fiber structure. The fragile structure of the paper bond is thereby changed positively. The moisture resistance and/or tear resistance of the paper layer are definitely improved by the polymer regions.
The thickness of the polymer region can be less than the thickness of the layers resting against one another in isolation, but in particular less than the thickness of the paper layer outside the polymer region. The gas permeability in the polymer region is thereby reduced to a fraction of the value outside the polymer region. In this region, the fiber layer—made of synthetic polymer fibers—is compressed into a compact material.
The fibers can be electrostatically charged in order to achieve an improvement in the filtering effect with respect to ultrafine dusts.
In addition to the fiber layer made of polymer fibers arranged on the downstream (clean-air)side, it is optionally possible to provide on the dusty-air side a further, supplementary fiber layer made of synthetic polymer fibers, and to bring about a further improvement in specific properties. This requires accepting, however, an increase in the cost of the dust filter bag. What is preferred in the context of the present invention is therefore an embodiment in which a layer of synthetic polymer fibers is provided only on the downstream side.
The fiber layer can be made of an at least inherently strong nonwoven fabric, so that even if the paper layer is completely destroyed, the dust filter bag remains sufficiently stable and effective in terms of filtration. Hygienic disposal of the dust filter bag that is at least partly filled with dust is thus possible even in such cases. The nonwoven fabric can be consolidated in moisture-stable fashion by mutual adhesive bonding and/or wrapping of the fibers and/or threads constituting it; optionally it can contain melted polymer regions and can additionally, by way of such regions, be consolidated within itself and joined to the paper layer. In this context, it has proven to be advantageous that the polymer regions be melted in window-like fashion. This results in consolidation zones that impart improved strength to the nonwoven fabric, in particular if the polymer regions are of bar-shaped configuration.
The polymer regions can be divided in the manner of a honeycomb or waffle pattern in order to form dust chambers. While the paper, because of its paper bond, behaves in rigid and inflexible fashion with respect to the air pressure that acts on it while the dust filter bag is being used as intended, what results on the downstream side is an elastic deformation of the fiber layer in the in-between zones of the honeycomb or waffle pattern. This results in the formation of dust chambers in which ultrafine dusts can collect. An embodiment of this kind has therefore proven to be excellent especially in terms of the retention of allergens.
The bars forming the polymer regions need not be configured in linked fashion, but rather can also be offset from one another, i.e. can be arranged without contact.
According to a further aspect of the invention, the dust filter bag is configured so that the fiber layer comprises at least two sublayers. This is particularly advantageous if the sublayers are to perform different functions.
In particular, the sublayer facing away from the paper layer of the dust filter bag can be made of a spun nonwoven fabric. This spun nonwoven fabric generally exhibits a high level of resistance to abrasion. This is important if the dust filter bag comes into contact with rough surfaces during manufacture, installation, or operation.
In addition, at least one sublayer adjoining the paper layer and made of microfibers can be present. In this layer, which can comprise a melt-blown nonwoven fabric, improved filtration properties are achieved, in particular in terms of ultrafine dusts, thus extending the field of application of the dust filter bag.
A particularly good cleaning effect with sufficient mechanical strength for the dust filter bag is obtained if the fiber layer made of microfibers has a weight per unit area of 5 g/m 2 to 40 g/m 2 (ISO 536), with a total weight of 5 to 50 g/m 2 for the fiber layer. The paper layer advantageously has a weight per unit area of 20 g/m 2 to 100 g/m 2 (ISO 536). The air permeability of the ready-to-use product is from 100 to 300 l/m 2 s at a differential pressure of 200 Pa (DIN 53887).
In order to ensure optimum processability in the production of the semifinished bags, the dust filter bag must exhibit properties similar to those of paper. This is ensured by the fact that the nonwoven fiber layers are joined in sufficiently permanent fashion to the paper. To achieve sufficient strength in the region of the longitudinal seam of the semifinished bag, the edge region is preferably particularly reinforced; this can be accomplished by way of a welding and/or adhesive bonding apparatus.
Because the nonwoven fabric layer is arranged on the downstream side, no welding of the nonwoven fabric plies occurs when the tube is cut to length, so that the tube ends can be reliably opened with an air pulse.
BRIEF DESCRIPTION OF THE DRAWINGS
An exemplary embodiment of the invention is depicted in the drawings, in which:
FIG. 1 shows a section taken through a three-ply dust filter bag constructed according to the principles of the invention;
FIG. 2 shows a plan view of the outer side, formed by the fiber layer, of the dust filter bag, with the melted polymer regions;
FIG. 3 a shows a section taken through the three-ply dust filter bag of FIG. 2 in the region of the melted polymer regions;
FIG. 3 b shows a scanning electron microscope image of the section of FIG. 3 a; and
FIG. 4 shows a cut-open folded vacuum cleaner bag.
DETAILED DESCRIPTION
FIG. 1 depicts a dust filter bag according to the invention. It comprises a paper layer 2 facing toward the dusty-gas side or intake side 1 . Facing toward the downstream, or clean-air side 3 is a fiber layer made of polymer material that is constituted from a spun nonwoven fabric 4 comprising thermoplastic fibers. Located between paper layer 2 and spun nonwoven fabric 4 is a further fiber layer made of polymer material, comprising a melt-blown nonwoven fabric 5 made of thermoplastic fibers.
In FIG. 1, paper layer 2 and melt-blow nonwoven fabric 5 rest substantially freely (i.e., without constraint) on one another, so that a cavity 6 is present. Spun nonwoven fabric 4 also rests unconstrainedly on melt-blown nonwoven fabric 5 , so that a cavity 7 is enclosed in some regions.
To enhance the strength of spun nonwoven fabric 4 , it can be consolidated at physically spaced-apart points by spot welding, as a result of which surface structures 8 are present.
FIG. 2 shows the downstream side surface of the dust filter bag. The melted polymer regions 9 , which are present in the form of bars 10 , are evident. Bars 10 are arranged at an offset from one another, and do not touch one another. They can be arranged in any desired pattern with respect to one another and can form, for example, a waffle or honeycomb pattern. Advantageously, the individual chambers 11 , 11 ′ bounded by the bars are configured continuously with one another via transverse connections, so as optimally to use the total filter area available and to prevent pressure peaks in individual chambers. For this purpose, the overall bar structures can also be constituted by a succession of individual welding zones which are at a distance from one another.
Bars 10 thus enclose dust pockets 11 , 11 ′ which, because of the noncontinuous structure of polymer regions 9 or bars 10 , are connected to and continuous with one another.
Since dust pockets 11 are not sealed off from one another, an exchange of material from one dust pocket 11 into an adjacent dust pocket 11 ′ is also possible, for example after clogging of the pores of one chamber has occurred, if those of an adjacent chamber are still available.
A wide variety of forms of the arrangement of the bars or other polymer regions is conceivable from this standpoint, in order to enhance the strength and at the same time allow dust pockets to be delimited from one another.
A bar-shaped pattern is shown, with inner bars 15 arranged about a center 14 and outer bars 15 arranged circumferentially with respect to them, each offset by 90 degrees, outer circle 17 around inner bars 15 being coincident with the inner circle of outer bars 16 . Bars 15 , 16 each extend out from center 14 at an angle of 45 degrees from the direction of travel.
Centers 14 , 14 ′, and 14 ″ are offset 9 degrees clockwise with respect to the direction of travel, and 39 degrees clockwise with respect to a line perpendicular to the direction of travel, so that they form an equilateral triangle.
In principle, it is also possible to use, instead of bars 15 , 16 arranged around centers 14 , 14 ′, and 14 ′, dot-shaped polymer regions arranged in centers 14 , 14 ′, 14 ″ themselves. In this case, however, the stability of the join decreases even though the joining surface remains the same, since no further structures are present between these centers. Material exchange from one dust pocket into the other is promoted, however, thus preventing premature clogging of subregions.
FIG. 3 a shows a section in the region of polymer regions 9 or bars 10 (FIG. 2 ). Polymer regions 9 can be produced by ultrasonic calendering. In this, the thermoplastic material of spun nonwoven fabric 4 and of melt-blown nonwoven fabric 5 is caused to melt at predetermined points, and is joined at high pressure to paper layer 2 . The type of paper is immaterial per se, provided it affords adequate filter properties.
In this process, the melted thermoplastic material of spun nonwoven fabric 4 and melt-blown nonwoven fabric 5 penetrates at least partially into paper layer 2 . In polymer regions 9 , the properties of spun nonwoven fabric 4 and melt-blown nonwoven fabric 5 are no longer retained because of the calendering; in particular, those regions are no longer active, or only insignificantly active, in terms of filtration.
The thickness of polymer region 9 is less than the thickness of paper layer 2 , so that polymer region 9 is particularly compact.
Between polymer regions 9 , cavities 6 form dust pockets 11 which receive the ultrafine dust, if the latter is not directly stored in the paper or in melt-blown nonwoven fabric 5 . Spun nonwoven fabric 4 , with higher strength values and hence relatively lower filter effectiveness, serves to protect melt-blown nonwoven fabric 5 , which is sensitive to abrasion. Its task is essentially to protect melt-blown nonwoven fabric 5 from abrasion and to impart to dust filter bag 12 a substantially improved tear resistance while preventing any appreciable impairment of the filtering effect, especially if wetting occurs. In particular, it prevents paper layer 2 of dust filter bag 12 from tearing and completely losing its filtering effect. It is even possible for paper layer 2 , once wetting has occurred, to dry out again during use as intended with no appreciable impairment of the filtering effect.
FIG. 3 b depicts a scanning electron microscope image of the nonwoven fabric configuration shown schematically in FIG. 3 a.
FIG. 4 depicts a three-ply dust filter bag 12 with multiple folds 13 . Paper layer 2 , spun nonwoven fabric 4 , and melt-blown nonwoven fabric 5 are not inserted into one another but rather, proceeding from a flat material, reshaped into dust filter bag 12 by being folded together.
Paper layer 2 , spun nonwoven fabric 4 , and melt-blown nonwoven fabric 5 are joined by way of polymer regions 9 . If liquid gets into the interior space delimited by paper layer 2 that faces toward the dusty-air side, and if paper layer 2 softens as a consequence thereof, spun nonwoven fabric 4 thus reliably holds dust filter bag 12 together.
In principle, a single nonwoven fabric made of polymer fibers can substitute for spun nonwoven fabric 4 and melt-blown nonwoven fabric 5 if the filter properties and strength properties are sufficient.
Lamination of paper layer 2 to fiber layer 4 , 5 can be accomplished with any usual method, for example hot melt laminating, application of adhesive compounds, etc., but is preferably performed by thermal welding.
An increased number of polymer regions can be provided in the edge region in order to enhance strength in the region of the longitudinal seam of the semifinished bag.
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A dust filter bag made of a fiber layer laminated together with a paper layer. The fiber layer is made of synthetic polymer fibers and is arranged on the downstream side of the paper layer. To increase the strength of the dust filter bag, the fiber layer contains melted polymer regions and by way of the polymer regions the fiber layer is additionally consolidated within itself and joined to the paper layer. The polymer regions have a welded area of 0.5 to 10% of the surface area, preferably 1 to 3%, thus resulting in sufficient laminate strength with a low pressure drop.
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BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to liquid containers used for storing cleaning liquid so as to be available in the cleaning process, specifically mopping buckets having divided liquid container sections for clean and dirty water.
2. Description of Prior Art
Prior art devices of this type have relied on a variety of bucket configurations associated with floor mopping use criteria, see for example U.S. Pat. Nos. 3,829,926, 4,319,761, 4,798,307, 5,918,343, 6,098,805 and 6,260,230.
In U.S. Pat. No. 3,829,926 a paint bucket is disclosed having four sides with integrated spout and roller engagement sides within.
U.S. Pat. No. 4,319,761 is directed to a mop bucket in which a clip configuration registerably engaged within a pair of buckets, securing them together.
U.S. Pat. No. 4,798,307 claims a compartmentalized cleaning buckets having a pair of reservoirs within for separation of clean water from dirty water during use.
A combination bucket and ringer is shown in U.S. Pat. No. 5,918,343 in which a bucket has an integrated mop/ringer therewith.
U.S. Pat. No. 6,098,805 is on a dual bucket assembly in which a bucket has two liquid retaining chambers therewithin that are nestable with a second identical dual bucket to be positioned within during storage or shipping configurations.
Finally, U.S. Pat. No. 6,260,230 is directed towards a floor washing and drying method using combination apparatus which has a first and second liquid reservoir within. A mop can be used with the first reservoir having a ringer associated therewith.
SUMMARY OF THE INVENTION
A cleaning bucket system for use in janitorial floor cleaning applications in which two reservoirs for water are required. The bucket system combines a mobile holding enclosure in which a pair of independent buckets are removably positioned therewithin. Each independent bucket can be used separated or as an integrated pair for clean and dirty water containment utilized in commercial cleaning applications.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front, side, top perspective view of the bucket system of the invention;
FIG. 2 is an exploded side elevational view illustrating removable interior buckets;
FIG. 3 is a top plan view; and
FIG. 4 is an end elevational view on lines 4 - 4 of FIG. 3 .
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 of the drawings, a cleaning system container assembly 10 of the invention can be seen having a main enclosure 11 . The enclosure 11 has oppositely disposed spaced parallel sidewalls 12 and 13 , interconnecting end walls 14 and 15 and an integral bottom 16 therebetween.
Pairs of wheel assemblies 17 are secured to the opposing enlarged bottom corner intersections extending from the respective wall corners thereof. The end wall 14 has a pour spout extension 14 A formed within upper perimeter edge. The end wall 15 extends angularly beyond respective upper perimeter wall edges 12 A and 13 A to accommodate mounting of an associated mop ringer assembly (not shown) as will be well understood by those skilled in the art.
The hereinbefore described side and end walls 12 , 13 and 13 , 14 , 15 and integral bottom 16 define a area 19 which could act as a holding tank for liquid, if required. The dimensional characteristics of the enclosure 11 are such that its longitudinal length is greater than its transverse dimension defining the respective end walls 14 and 15 . A pair of independent bucket inserts 20 and 21 , best seen in FIGS. 1 and 2 of the drawings, each defined by multiple wall pairs 20 A, 20 B, and 21 A, 21 B, respectively with interconnecting bottoms 20 C and 21 C adapted for holding a liquid as will be understood by those skilled in the art. The bucket's respective walls have corresponding upper lip edges 22 and 23 thereabout and each have an integrated pour spout 24 and 25 formed in one of the wall pairs 20 A and 21 A respectively.
In this preferred embodiment of the invention, indexing ribs 26 may extend vertically on inner sidewall surfaces thereof midway of the longitudinal length of the enclosure 11 thereof in oppositely disposed aligned orientation to one another. The indexing ribs 26 act as positioning guides for insertion of the respective buckets 20 and 21 which are oriented for the clearance of their respective molded pour spouts 24 and 25 , as best seen in FIG. 2 of the drawings and in dotted lines in FIG. 4 of the drawings.
Each of the hereinbefore described bucket inserts 20 and 21 registerably engage the corresponding sidewalls 12 and 13 and respective end walls 14 and 15 and extend marginally thereabove.
Bucket handles 29 and 30 are pivotally secured to the appropriate oppositely disposed walls 20 B of the bucket inserts 20 and 21 for ease of positioning and removal as will be evident to one skilled in the art.
The dual bucket inserts 20 and 21 provide for independent removable liquid reservoirs (for clean and dirty water) within the integrated movable cleaning container assembly 10 of the invention. Since the bucket inserts 20 and 21 can be selectively removed via their handles 29 and 30 for filling and dumping an improved and efficient working environment can be achieved.
It will also be evident from the above description that by the corresponding shape of the bucket inserts 20 and 21 that they will registerably engage and be properly positioned within the end source 11 for ease of access during use and afford convenient and simple filling and emptying which is not evident in prior art integrated divided multiple enclosure configurations which are fixed therewithin.
It will thus be seen that a new and novel cleaning container assembly has been illustrated and described and it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.
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A janitorial bucket conveyance system that combines a mobile container receiving containment enclosure with multiple insertable independent identical buckets for use in commercial cleaning environments. The independent identical buckets are positioned for use and transportation within the enlarged mobile containment enclosure onto which cleaning associated accessory can be selectively mounted related to floor washing requirements.
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CROSS-REFERENCE TO RELATED APPLICATION
This is a divisional application of Petitioner's earlier application Ser. No. 08/921,157 filed Aug. 29, 1997, now U.S. Pat. No. 5,934,030, and entitled A DOOR FRAME.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a door frame and more particularly to a door frame comprised of two unitary door frame members.
2. Description of the Related Art
Door frames traditionally include a pair of vertically disposed side jambs and a head jamb extending across the upper ends of the side jambs. One of the side jambs is usually termed a hinge jamb while the other side jamb is usually termed a latch jamb. The door frame is normally positioned in a door opening formed in a wall surface. Vertical and horizontal trim members are then positioned at the opposite sides of the door frame to cover the gap between the door frame and the door opening. Traditionally, these door frame members are made of wood, aluminum, steel, plastic and/or fiberglass. The members are normally fabricated/manufactured from boards, bent steel plates, extruded aluminum, extruded plastic and/or pultruded fiberglass. All of these methods of manufacture produce straight structural members which must be joined at their junctures. Necessarily, because of the above-described construction of the door frame, joints are present between the side jambs and head jamb, as well as miter joints being present between the vertical and horizontal trim members. Additionally, joints are formed at the juncture of the trim members and the jambs. A wood door is normally hingedly secured to the hinge jamb. The door frame may be sold as a pre-hung door assembly or the door may be installed in the door frame after the door frame has been installed in the door opening.
If the door frame described above is used in a food or meat processing plant, the joints therein present a space in which bacteria may grow and which makes cleaning thereof difficult. Inasmuch as food and meat processing plants are frequently washed or cleaned with corrosive chemicals, the steel door frames and doors secured thereto rapidly deteriorate. However, even stainless steel side jambs and head jambs still have joints therebetween unless the joints are welded and ground smooth. Usually, these joints are the weakest points in the frame and can separate or cause difficulty during installation and, in some cases, open or separate after installation. Further, if separate steel trim members are used, miter joints exist between the vertical and horizontal trim members. Additionally, since wall thicknesses vary, it is necessary to fabricate door frames of varying sizes to accommodate the same.
SUMMARY OF THE INVENTION
A door frame comprised of first and second door frame members constructed of a fiberglass material. The first door frame member includes a first side jamb, a second side jamb, and a first head jamb extending between the upper ends of the first and second side jambs. The first door frame member includes a trim section for overlying a first wall surface adjacent a door opening in a wall and further includes an inside section which extends substantially perpendicularly from the trim section for extending into the door opening. The second door frame member includes a first side jamb, a second side jamb, and a first head jamb extending between the upper ends of the first and second side jambs of the second door frame member. The second door frame member includes a trim section for overlying a second wall surface adjacent the door opening and further includes an inside section extending substantially perpendicularly from the trim section for extending into the doorway opening. Each of the first and second door frame members are of unitary construction. When the first and second door frame members are installed in the door opening, one of the door frame members is received by a recessed portion in the other door frame member. The two frame members are then connected together by mounting screws and/or adhesive to form a unitary frame. A fiberglass door is hingedly secured to one of the side jambs of one of the door frame members. The door frame member upon which the door is hingedly mounted is provided with an integrally formed door stop member. The hinge edge of the door is provided with vertically spaced-apart metal strengthening plates embedded therein. The side jamb having the door hingedly secured thereto is also provided with a plurality of vertically spaced metal strengthening plates embedded therein. The strengthening plates are drilled and tapped to serve as a nut to receive machine screws securing the hinges which hingedly secure the door to the side jamb.
It is therefore a principal object of the invention to provide a unitary door frame.
Still another object of the invention is to provide a door frame comprised of first and second door frame members of unitary construction.
Still another object of the invention is to provide a door frame comprised of a fiberglass material and which does not have joints at the juncture between the side and head jambs therein which could harbor bacteria.
Still another object of the invention is to provide a door frame which may accommodate various wall thicknesses.
Still another object of the invention is to provide a door frame which is economical of manufacture, durable in use and refined in appearance.
Still another object of the invention is to provide a door frame which is comprised of strong side jambs, head jamb and connecting corners to facilitate the installation thereof and produce a strong and durable door frame.
Still another object of the invention is to provide a door frame in which the glass fiber reinforcement is continuous through the juncture of the head and side jambs, producing a door frame that is strong and dimensionally correct for receipt of the door and greatly ease the installation process.
Still another object of the invention is to provide a door frame including strengthening plates for securing hinges and other hardwares provided and which are totally enclosed in the reinforced fiberglass laminate during the molding process.
These and other objects will be apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the door frame of this invention having a door hung therein;
FIG. 2 is an exploded perspective view of the door frame of FIG. 1 with portions thereof cut away to more fully illustrate the invention;
FIG. 3 is a partial sectional view of the door frame of this invention installed in a door opening;
FIG. 4 is a partial sectional view of a modified form of the invention; and
FIG. 5 is a partial sectional view illustrating how the door frame of this invention may accommodate walls having various thicknesses.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The door frame assembly of this invention is referred to by the reference numeral 10 and is designed to have a door 12 pre-hung therein. Door frame assembly 10 includes door frame members 14 and 16.
Door frame member 14 is of unitary construction and includes side jambs 18 and 20 having a head jamb 22 extending between the upper ends thereof. Side jamb 18 is normally referred to as a latch jamb while side jamb 20 is normally referred to as a hinge jamb.
Side jambs 18 and 20 and the head jamb 22 are provided with an inwardly extending lip 24 which is designed to engage the wall surface 26 of wall 27 which surrounds the door opening 30 created in the wall 27. The side jambs 18 and 20 and the head jamb 22 also include a trim section 28 which is positioned adjacent wall surface 26 to cover any gap between the door opening and the door frame. Each of the side jambs 18 and 20 and the head jamb 22 are also provided with an inside section 32 which extends substantially perpendicularly from trim section 28 and which extends into the door opening, as seen in FIG. 3. Inside section 32 is provided with a recessed area referred to generally by the reference numeral 34 which is positioned adjacent wall 26, as seen in FIG. 3. Inside section 32 is provided with a plurality of vertically spaced-apart reinforcing or support plates 35 embedded therein. Side jamb 20 is provided with a plurality of vertically spaced-apart metal reinforcing or support plates 36 encased therein for supporting the hinges 38 operatively secured thereto by machine screws 40. The plates 36 are tapped and drilled to enable the machine screws 40 to be threadably secured thereto.
Door frame member 16 is of unitary construction and includes side jambs 42 and 44 and head jamb 46 extending therebetween. As seen in the drawings, the side jambs 42 and 44 and the head jamb 46 are of unitary fiberglass construction. Door frame member 16 includes a trim section 46, inside section 48 and lip 50, as seen in the drawings. As seen in the drawings, lip 50 engages wall surface 52 of wall 28 and trim section 46 extends substantially parallel to the surface 52 of wall 28. Inside section 48 extends substantially perpendicularly from trim section 46 and is received in the recessed portion 34 of the door frame member 14. The door frame members 14 and 16 are secured together by means of adhesive applied in the recess 34 and the screws 54 extending through inside sections 32 and 48, as best illustrated in FIG. 3. It should be noted that if the door opening is larger than that required by the door, inside section 48 and inside section 32 may be spaced inwardly from wall 27 by inserting a spacer or spacers between section 32, 48 and the wall 27 with structural foam being injected into the remaining cavity. As also best illustrated in FIG. 3, inside section 32 of door frame member 14 is thickened to provide a door stop member referred to generally by the reference numeral 56.
FIG. 5 illustrates the manner in which door frame member 16 may be trimmed so that the door frame 10 can be fitted to walls having various thicknesses. As seen, the installer determines the distance "d" from the inner end of recess 34 to the exterior surface of wall 52. The installer then measures that distance "d" from the inner end of lip 50 inwardly along trim section 48. The remaining portion of trim section 48 is then removed with the trimmed portion then being received within the recess 34 to provide the fit illustrated in FIG. 3.
FIG. 4 illustrates the manner in which the door frame 10 may be installed in an opening 58 formed in a concrete wall 60. A plurality of L-shaped plates 62 are installed in the concrete wall in the manner illustrated in FIG. 4. The lips 24 and 50 on the door frame members 14 and 16 are then positioned with respect to the plate 62, as illustrated in FIG. 4, so that the door frame will be positioned in the opening. Heavy gage wire clips could also be used in place of plates 62. T-shaped metal plates could also be partially embedded in the wall 60 if desired. In the embodiment of FIG. 4, door frame members 14 and 16 are joined together at the factory with epoxy adhesive to form a single unitary door frame prior to shipment.
The door frame members 14 and 16 are preferably constructed of a fiber reinforced plastic. Preferably, the fibers are glass fibers. Door frame member 14 is formed by providing a closed mold having the glass fibers and the steel plates 36 placed therein and then injecting the resin into the mold to form a unitary fiber reinforced door frame member. Door frame member 16 is formed in the same manner except for the lack of steel reinforcing plates.
Door 12 is provided with an outer skin or shell 64 of fiberglass construction. A U-shaped channel 66 of fiberglass construction is positioned in the door around the periphery thereof, as illustrated in FIGS. 2-4. A plurality of vertically spaced-apart metal plates 68 are positioned in the channel 66 as seen in the drawings. The numeral 70 refers to glass reinforcement fibers which are injected with the resin at the same time as the skin to integrally encase the metal backing plates 68 in the fiberglass laminate for additional strength. The area inside channel 66 is filled with a high density foam 72 while the remaining interior of the door 12 is filled with a low density foam material 74. The door 12 is secured to the hinges 38 by screws 76 extending through the hinge side of the door 12, through the metal reinforcing plates 68 and through the fiberglass reinforcement 70 encasing the metal plates 68.
Thus it can be seen that a novel door frame of fiber reinforced plastic (fiberglass) construction has been provided wherein there are no joints which could harbor bacteria or the like. It can also be seen that the door frame of this invention permits the door frame to accommodate various wall thicknesses by simply trimming the inside section of door frame member 16. The door frame of this invention is durable as well as refined in appearance.
It is believed that the door itself is also unique in its construction. The two densities of foam core provide an exceptionally strong door in areas where hardware and other items can be attached and where the door edge itself is likely to experience abuse. The center core, which is also strong, is of lower density to reduce the overall weight of the door. One method of making the core is to form a large block of low density foam and then place the low density block in a mold which is larger than the low density block and inject high density foam in the cavity around the low density foam. The resultant structure may then be sliced much like bread or a jelly roll with a filled center, with the slice being used as the core material.
Another way to fabricate the door is to put separate sections in the mold of the right thicknesses, which allows the fabricator to vary the thicknesses of the reinforcement at the edges or add additional reinforcement at the joint between the two types of foam. When the door is completed, it is a single one-piece seamless unit with exceptional strength that can be made with fire-resistant and ballistic-resistant materials as well as standard resin and glass reinforcement fibers.
Thus it can be seen that the invention accomplishes at least all of its stated objectives.
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A door of fiberglass construction is described and which comprises an outer fiberglass skin having an interior compartment filled with a foam material with the skin enclosing the foam material and being of seamless construction. The foam material includes a high density foam material along at least portions of the periphery of the interior compartment and an inner member comprised of a low density foam material.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a technical field of aluminum electrolysis, and more particularly to an aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations.
[0003] 2. The Prior Arts
[0004] At present, the industrial pure aluminum is manufactured through the electrolysis in molten cryolite-alumina system. The specially used equipment is an electrolytic cell having a cell lining containing carbon material. The materials installed between a steel-made cell shell and the carbon lining are refractory materials and heat insulating bricks. The carbon lining of electrolytic cell is generally composed through laying carbon bricks (or blocks). The carbon brick (or block) is anthracite coal or graphite material which has better corrosion resistances for sodium and electrolyte, or is a mixture of the above two. Connecting locations of the mentioned material or components are tamped with carbon paste made of the mentioned carbon material. Steel bars are installed at the bottoms of carbon blocks provided at the bottom of the electrolytic cell and the steel bars protrude to the exterior of the cell shell. The steel bars are often named as the cathode steel bars of electrolytic cell. A carbon anode made of petroleum coke is hanged above the electrolytic cell, and a metal-made anode rod is installed on top of the anode of electrolytic cell. The electric current can be introduced through the anode rod. The molten cryolite and molten metallic aluminum with the temperature of 940˜970° C. are provided between the carbon cathode and the carbon anode in electrolytic cell. The aluminum fluid does not dissolve with the molten electrolyte, and the density of aluminum is larger than that of molten electrolyte, so aluminum is under the molten electrolyte and in contact with the carbon cathode. When Direct current (DC) is introduced through the carbon anode in electrolytic cell and is guided out from the carbon cathode, because the molten electrolyte is an ionic conductor, the molten electrolyte containing alumina generates an electrochemical reaction at the two electrodes. The result of this reaction is that oxygen generated through ion containing oxygen discharging electricity at the anode reacts with the carbon at the carbon anode. The electrolytic product in a form of CO 2 is discharged from the surface of the anode. The ion containing aluminum discharges electricity at the cathode, and obtains three electrons at the cathode so as to form metallic aluminum. The cathode reaction is processed at the surface of the metallic aluminum fluid in the electrolytic cell. The distance between the surface of the cathode and the bottom surface of the carbon anode is defined as an anode-cathode distance (ACD) in electrolytic cell. In an industrial aluminum electrolytic cell, the ACD is 4˜5 cm. The ACD is a very important parameter. An overly high or an overly low ACD would affect the aluminum electrolytic production, the reason is: an overly low ACD would increase the reaction between the metallic aluminum dissolved from the cathode surface into the molten electrolyte, and the anode gas; the current efficiency (CE) is thereof lowered. An overly high ACD would increase the cell voltage, and the DC power consumption for the aluminum production is therefore increased.
[0005] For the aluminum electrolytic production, the highest current efficiency and the lowest power consumption of electrolytic cell are desired. The DC power consumption can be obtained by the following formula:
[0000] W (KWH/per ton of aluminum)=2980× Va/ CE (1)
[0000] Wherein Va is the average cell voltage (V), and CE is the current efficiency (%).
[0006] From the mentioned formula, it is known that lowering the power consumption of the aluminum electrolytic production can be achieved by increasing the current efficiency and lowering the average cell voltage.
[0007] If the cell voltage decreases 0.1 V, the DC power consumption of electrolytic cell can reduce about 320 (KWH/per ton of aluminum). If the current efficiency of electrolytic cell increases 1%, the DC power consumption can reduce about 150 (KWH/per ton of aluminum). As a result, without any influencing the current efficiency, lowering the cell voltage plays a very important role at the aluminum electrolytic production. If lowering the cell voltage and increasing the current efficiency can be achieved at the same time, then the DC power consumption of aluminum electrolytic production can be greatly affected.
[0008] The ACD is a major parameter for determining the value of cell voltage, for a general industrial electrolytic cell, if the ACD reduces 1 mm, the cell voltage can be decreased 35 mV. From the mention formula (1), it is known that in a stat of not reducing the current efficiency, the DC power consumption of aluminum electrolytic production can decrease 100 (KWH/per ton of aluminum). As such, in the state of not reducing the current efficiency of electrolytic cell, lowering the ACD means a lot to the power consumption of aluminum electrolytic production. Generally, the ACD for an industrial aluminum electrolytic cell is 4.5˜5.0 cm, and a cold steel fiber, with a diameter of 15 mm and formed with a hook, is uprightly inserted in the molten electrolyte in electrolytic cell and is vertically hooked on an anode surface for about one minute, then is removed from the electrolytic cell. Through utilizing the boundary surface between aluminum and electrolyte, the distance between the molten aluminum surface and the anode bottom surface can be observed. As such, the distance value obtained through the mentioned method is not the real ACD of electrolytic cell. This is because when the metallic aluminum surface is affected by fluctuations of metallic aluminum surface caused by the electromagnetic field force and the anode gas discharged from the anode in the electrolytic cell. With references of other technical papers, the fluctuation peak of the cathode molten aluminum surface of electrolytic cell is about 2.0 cm. With no molten aluminum fluctuation, the electrolytic production can be processed with the ACD of 2.0˜3.0 cm in the electrolytic cell. The cell voltage can lower 0.7˜1.0 V, so an object of saving 2000˜3000 (KWH/per ton of aluminum) can be achieved.
[0009] Based on the mentioned arts and theories, Mr. Nai-Xiang Feng has invented a cathode carbon block having convex wall members along the longitudinal direction of the carbon block, which is the same direction of potline, and an aluminum electrolytic cell having said cathode carbon block structures. Said electrolytic cell has been tested in a large-scale electrolytic cell at the Tian-Tai Aluminum Co., based in Chong Qing, China, the test is to lower the cell voltage from 4.1 V to 3.8 V, and an obvious power saving effect is obtained. But the test results have also found: (1) the cathode structure of the mentioned electrolytic cell has a function of weakening molten aluminum fluctuations from the longitudinal direction of the electrolytic cell, which is perpendicular to direction of the potline, but can not weaken the molten aluminum fluctuations from the transversal direction of the electrolytic cell; and (2) stress differentiations at the connecting locations of the wall protruding from the cathode carbon blocks and the cathode carbon block base are high, thus the protrusions at the connecting locations are fragile and easy to be broken. The broken protrusions may impact the production operation and shorten the cell life.
SUMMARY OF THE INVENTION
[0010] In view of the disadvantages and problems of the mentioned aluminum electrolytic cell with cathode carbon block structures, the present invention provides an aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations.
[0011] The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations provided by the present invention includes an electrolytic cell shell, heat insulating materials, bottom refractory bricks and heat insulating bricks, cathode carbon blocks, lined carbon bricks, carbon ramming paste, refractory concrete and cathode steel bars. The top surface of the cathode carbon block is installed with at least one convex structure, each convex structure integrates with the cathode carbon block. The convex structures are arrayed to be parallel or vertical with the axis of the cathode carbon blocks or to be mixed with the above two; wherein the convex structure vertical to the axis of the cathode carbon blocks is defined as a horizontal convex structure, the convex structure parallel to the axis of the cathode carbon blocks is defined as a vertical convex structure.
[0012] The material of which the cathode carbon blocks with convex structures are made is the same as the material of which a conventional cathode carbon block of electrolytic cell is made, which is a anthracite coal, artificial graphite debris, or a mixture of anthracite coal and artificial graphite debris, or is a graphitized or semi-graphitized cathode carbon block.
[0013] The cross section of the convex structure is in a rectangular or trapezoidal shape or in a mixed shape of rectangle and trapezoid, wherein when the cross section is in a mixed shape of rectangle and trapezoid, the rectangle is above the trapezoid.
[0014] The width of the cross section of the convex structures on the cathode carbon block is set with respect to the width of the cathode carbon block base. In a state that the width of the cathode carbon block base is 400 mm, the width of the upper portion of the cross section of the horizontal convex structure is 150˜250 mm, the width of the lower portion thereof is 200˜300 mm. The vertical convex structures are arranged as a single-row or a dual-row arrangement, when being arranged as the single-row arrangement, the width of the upper portion of the cross section of the vertical convex structure is 150˜250 mm, the width of the lower portion thereof is 200˜300 mm; when being arranged as the dual-row arrangement, the width of the upper portion of the cross section of the vertical convex structure is 80˜120 mm, the height of the cross section of the vertical convex structure is 80˜160 mm. If the width of the cathode carbon block base is increased, the size of the cross section of the convex structure is proportionally increased.
[0015] When the convex structures on the cathode carbon block are all horizontal convex structures, each horizontal convex structure on two adjacent cathode carbon blocks are staggered with each other. The length of the horizontal convex structure is the same or 40˜60 mm smaller than the width of the cathode carbon block base; the minimum distance between the adjacent horizontal convex structures on a same cathode carbon block is 300·500 mm. The center location of the cathode carbon block, which is closest to the aluminum outlet, is a gap defined by two horizontal convex structures.
[0016] When the convex structures on the cathode carbon block are all vertical convex structures, the axis of each vertical convex structure is parallel to the axis of the cathode carbon block base, the length thereof is defined with respect to at least two vertical convex structures aligned on each cathode carbon block. The distance between two ends of the cathode carbon block and the bottoms of the vertical convex structures arranged at the two ends is 30˜50 mm. The vertical convex structures are arranged at two ends with respect to the center of the cathode carbon block base, the gap defined by two vertical convex structures arranged at the middle directly faces the aluminum outlet. The minimum distance between the adjacent vertical convex structures on a same cathode carbon block is 100˜200 mm.
[0017] When the convex structures of the cathode carbon block are mixedly arranged, the heights of the horizontal convex structures and the vertical convex structures are the same, the distance between the horizontal convex structure and the vertical convex structure is 30˜100 mm. The convex structure at the center of the cathode carbon block base is the horizontal convex structure. On the cathode carbon block closest to the aluminum outlet, the minimum distance between the horizontal convex structure near the aluminum outlet and the outer lateral surface of the cathode carbon block base is 30˜300 mm. The outer lateral surface of the cathode carbon block base is defined as the lateral surface of the cathode carbon block that faces the cell lining of the aluminum outlet. The mixed arrangements of the horizontal convex structures and the vertical convex structures are categorized to a discontinuous arrangement and a continuous arrangement, when being arranged as the discontinuous arrangement, the distance between the horizontal convex structure and the vertical convex structure is 30˜100 mm; when being arranged as the continuous arrangement, the horizontal convex structure is connected with the vertical convex structure.
[0018] When the convex structures of the cathode carbon block are mixedly arranged, the arrangements of the vertical convex structures can be categorized to a single-row arrangement and a dual-row arrangement, when being arranged as the single-row arrangement, the vertical convex structures and the horizontal convex structures on each cathode carbon block are staggered with each other; when being arranged as the dual-row arrangement, every two vertical convex structures aligned as two rows on each cathode carbon block is defined as one set, each set of vertical convex structure is staggered with each horizontal convex structure. The minimum distance between a set of vertical convex structure is 30˜100 mm. The mixed arrangements of the horizontal convex structures and the vertical structures are categorized to a discontinuous arrangement and a continuous arrangement, when being arranged as the discontinuous arrangement, the distance between the horizontal convex structure and the vertical convex structure is 30˜100 mm; when being arranged with as the continuous arrangement, the horizontal convex structure is connected with the vertical convex structure.
[0019] The installation of cathode carbon block near the aluminum outlet can ensure a convenient operation of the aluminum outlet.
[0020] In the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the present invention, the manufacturing method of cathode carbon block having convex structures is: the conventional material for manufacturing cathode carbon block is adopted, and a blank material is formed with a means of vibration molding, then is baked; or an elongated blank material is firstly manufactured with the means of vibration molding then is baked, and the required shape is formed through mechanical processing.
[0021] The structure of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the present invention is: the lateral sides of the interior of the electrolytic cell shell are installed with lined carbon bricks, the cathode at the cell bottom is configured by at least eight cathode carbon blocks having convex structures. A 20˜40 mm gap is formed between the adjacent cathode carbon blocks, and the gap is tamped with carbon ramming paste. Refractory concrete is used for tamping under the lined carbon bricks and above the bottom refractor bricks and heat insulating bricks. The carbon ramming paste is used between the lined carbon bricks and the cathode carbon blocks. The bottoms of the cathode carbon blocks are connected with cathode steel bars, and two ends of each cathode steel bar are protruded outside the electrolytic cell serving as the cathode of the electrolytic cell.
[0022] The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the present invention is installed with cathode carbon blocks having convex structures on the cell lining at the cell bottom. The width of the carbon block base, which is a non-convex structure at the lower portion of the cathode carbon block, is wider than the width of the convex structures installed at the upper portion, and the carbon ramming paste is only used to tamp the space between the non-convex structures of the cathode carbon blocks. So the bottom of the electrolytic cell is formed with rows of convex structures configured by the convex structures of the cathode carbon blocks having protrusions on the top surface. The convex structures are the compositions of the cathode carbon blocks of the electrolytic cell.
[0023] The material of which the lined carbon bricks are made is anthracite coal or artificial graphite debris or a mixture of anthracite coal and artificial graphite debris, or silicon carbide.
[0024] In the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the present invention, a groove is formed between two adjacent cathode carbon blocks, the installation method of groove is: two lateral sides of the top surface of the cathode carbon block base are installed with angular concave corners, and the groove is defined between two opposite angular concave corner respectively on two adjacent cathode carbon blocks and the top surface of carbon ramming paste; during production, the groove is filled with sludge made of cryolite and alumina for preventing the cathode steel bars from being molten by the molten aluminum; the depth of the angular concave corner is 20˜50 mm with respect to the top surface of the cathode carbon block base, the width thereof is 20˜50 mm, the length thereof is the same as the length of the cathode carbon block; so the depth of the groove is 20˜50 mm, and the width thereof is 80˜140 mm.
[0025] The structure of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the present invention is similar to the conventional industrial aluminum electrolytic cell, the obvious difference is that the shape and structure of the cathode carbon blocks at the bottom of the electrolytic cell are different from those in the conventional electrolytic cell. Moreover, the lateral sides and bottom side of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations are quipped with a better design for heat insulation.
[0026] The manufacturing method of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the present invention is as follows:
1. An aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations is provided; 2. The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of this invention is processed with a baking operation of baking with flames or firstly baking with flames then baking aluminum fluid, after the baking operation, the electrolytic cell is started-up with a conventional means of electrolytic cell start-up; 3. In the normal production technology management after the electrolytic cell is started, the aluminum level in the electrolytic cell is 10˜50 mm after the aluminum is outputted and calculated from the top surface of convex structure. In the normal production, the ACD of the electrolytic cell is 25˜40 mm, the cell voltage is 3.3˜3.9 V. 4. In the electrolytic process, an alumina electrolyte sludge groove installed above the carbon ramming paste and between the cathode carbon block bases is filled with sludge made of cryolite and alumina, at the electrolysis temperature, the sludge is molten for sealing cracks generated after the carbon ramming paste is sintered. As such, the cathode steel bars are protected from being molten by the molten aluminum and the electrolytic cell is protected from being damaged Beside the abovementioned disclosures, in the normal production, arts adopted in the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of this invention are the same as the arts adopted in conventional aluminum electrolytic cell with cathode structures. The technical working conditions of the arts are as follows. The electrolyte level is 15˜25 cm, the molar ratio of electrolyte is 2.0˜2.8, the concentration of alumina is 1.5˜5%, and the electrolysis temperature is 935˜975° C.
[0031] In the state of the mentioned arts, the electrolytic reaction at the cathode of the electrolytic cell is:
[0000] Al 3+ (compound)+3 e =Al
[0032] The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations provided by the present invention is able to reduce the flow rate of molten aluminum and shortening the vertical and horizontal fluctuations of the molten aluminum, so the stability of the metallic aluminum is improved, and the aluminum dissolved loss is reduced, the current efficiency is increased and the ACD can be decreased, such that the cell voltage and the power consumption for aluminum electrolytic production are lowered, and the strengths at the connecting locations of the protruded wall members and the bases are enhanced so as to lower the damage and prolong the service life. The installation of convex structures in a trapezoidal shape or a mixed shape of rectangle and trapezoid can ensure the convex structures have sufficient strengths.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The present invention will be apparent to those skilled in the art by reading the following detailed description of a preferred embodiment thereof, with reference to the attached drawings, in which:
[0034] FIG. 1 is a schematic view of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the first embodiment of the present invention;
[0035] FIG. 2 is a schematic cross sectional view of FIG. 1 along a B-B plane;
[0036] FIG. 3 is a schematic view of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the second embodiment of the present invention;
[0037] FIG. 4 is a schematic cross sectional view of FIG. 3 along a B-B plane;
[0038] FIG. 5 is a schematic view of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the third embodiment of the present invention;
[0039] FIG. 6 is a schematic cross sectional view of FIG. 5 along a B-B plane;
[0040] FIG. 7 . is a schematic view of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the fourth embodiment of the present invention;
[0041] FIG. 8 is a schematic cross sectional view of FIG. 7 along a B-B plane;
[0042] FIG. 9 is a schematic view of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the fifth embodiment of the present invention;
[0043] FIG. 10 is a schematic cross sectional view of FIG. 9 along a B-B plane;
[0044] FIG. 11 is a schematic cross sectional view of the trapezoidal horizontal convex structure of the embodiments of the present invention;
[0045] FIG. 12 is a schematic cross sectional view of the horizontal convex structure with a mixed shape of rectangle and trapezoid of the embodiments of the present invention;
[0046] FIG. 13 is a schematic cross sectional view of the single-row trapezoidal vertical convex structure of the embodiments of the present invention;
[0047] FIG. 14 is a schematic cross sectional view of the single-row vertical convex structure with a mixed shape of rectangle and trapezoid of the embodiments of the present invention;
[0048] FIG. 15 is a schematic cross sectional view of the dual-row trapezoidal vertical convex structure of the embodiments of the present invention; and
[0049] FIG. 16 is a schematic cross sectional view of the dual-row vertical convex structure with a mixed shape of rectangle and trapezoid of the embodiments of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0050] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
First Embodiment
[0051] As shown in FIG. 1 and FIG. 2 , the present invention provides an aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations. The exterior of the aluminum electrolytic cell is installed with a steel-made electrolytic cell shell 1 , heat insulating material 2 equipped to the electrolytic cell shell 1 are asbestos plates, bottom refractor bricks and heat insulating bricks 3 are installed on the bottom asbestos plate of the heat insulating material 2 , cathode carbon blocks 4 having convex structures and cathode steel bars 8 are installed on the top surface of the bottom refractory bricks and heat insulating bricks 3 .
[0052] The inner lateral sides of the electrolytic cell are provided with lined carbon bricks 5 . The cathode at the cell bottom of the electrolytic cell is configured by at least eight cathode carbon blocks 4 having convex structures and being installed cathode steel bars 8 at the bottoms. Each cathode carbon block 4 is horizontally disposed in the electrolytic cell, in other words the length direction of the cathode carbon block 4 is perpendicular to the length direction of the electrolytic cell. A 2040 mm gap is formed between the adjacent cathode carbon blocks 4 , and the gap is tamped with carbon ramming paste 6 . Refractory concrete 7 is used for tamping under the lined carbon bricks 5 and above the bottom refractor bricks and heat insulating bricks 3 . The carbon ramming paste 6 is used for tamping between the lined carbon bricks 5 and the cathode carbon blocks 4 . The bottoms of the cathode carbon blocks 4 are respectively installed with cells for accommodating the cathode steel bars 8 , and two ends of each cathode steel bar 8 are protruded outside the cell shell 1 for serving as the cathode of the electrolytic cell.
[0053] The convex structures of each cathode carbon block in the aluminum electrolytic cell with convex structures are horizontal convex structures. The distance between the adjacent horizontal convex structures on a same cathode carbon block is 300˜500 mm; the horizontal convex structures on two adjacent cathode blocks are staggered with each other.
[0054] FIG. 11 shows the cross sectional view of the horizontal convex structure of the cathode carbon block 4 . The cross section of the horizontal convex structure is in a trapezoidal shape, the width of the top surface is 150˜250 mm, the width of the lower portion connected to the carbon block base is 200˜300 mm, and the length is the same as the width of the cathode carbon block base.
[0055] Wherein on the cathode carbon block closest to an aluminum outlet, the aluminum outlet directly faces the gap defined by two horizontal convex structures.
[0056] The manufacturing method of cathode carbon block having convex structures is: the conventional material for manufacturing cathode carbon block is adopted, and a blank material is formed with a means of vibration molding, then is baked; or an elongated blank material is firstly manufactured with the means of vibration molding then is baked, and the required shape is formed through mechanical processing.
[0057] The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of this invention is processed with a baking operation of baking with flames or firstly baking with flames then baking aluminum fluid. After the baking operation, the electrolytic cell is started-up with a conventional means of electrolytic cell start-up.
[0058] In the normal production technology management after the electrolytic cell is started-up, the aluminum level in the electrolytic cell is 10˜50 mm after the aluminum is outputted and calculated from the top surface of convex structure. In the normal production, the ACD is 25˜40 mm, the cell voltage is 3.3˜3.9 V.
[0059] An alumina electrolyte sludge groove disposed on top of the carbon ramming paste and between two cathode carbon block bases at the bottom of the aluminum electrolytic cell is filled with alumina, in which a part thereof is powder, and cryolite powder. At the electrolysis temperature, the cryolite is molten so as to seal cracks or slits of the paste disposed at the cell bottom, such that the molten aluminum is prevented from leaking from the cracks and slits and from penetrating to the cell bottom. As such, the cathode steel bars are protected from being molten and the electrolytic cell is protected from being damaged. Beside the mentioned two points, in the normal production, arts adopted in the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of this invention are the same as the arts adopted in conventional aluminum electrolytic cell with cathode structures. The technical working conditions of the arts are as follows. The electrolyte level is 15˜25 cm, the molar ratio of electrolyte is 2.0˜2.8, the concentration of alumina is 1.5˜5%, and the electrolyte temperature is 935˜975° C.
[0060] After being tested, when the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of the present invention is operated, the aluminum level surface is stable, the power consumption is low, and the service life is obviously prolonged.
Second Embodiment
[0061] The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of this invention is shown in FIG. 3 and FIG. 4 . The whole structure of the electrolytic cell is the same as the electrolytic cell disclosed in the first embodiment; the difference is that convex structures on the cathode carbon blocks are mixedly arranged with horizontal convex structures and vertical convex structures. The horizontal convex structure and vertical convex structures on each cathode carbon block base are staggered with each other. The quantity of horizontal convex structure is one, the length of the horizontal convex structure is the same as the width of the cathode carbon block base. The length of vertical convex structure is defined with respect to two vertical convex structures aligned on each cathode carbon block base. On a cathode carbon block, the distance between two ends of the cathode carbon block and the bottoms of the vertical convex structures arranged at the two ends is 30˜50 m. On the same cathode carbon block, the distance between the adjacent horizontal convex structure and the vertical convex structure is 30˜100 mm.
[0062] FIG. 12 shows the cross sectional view of the horizontal convex structure of the cathode carbon block 4 . FIG. 14 shows the cross sectional view of the vertical convex structure. The cross section of the convex structure is in a mixed shape of rectangle and trapezoid, the width of the top surface of each convex structure is 150˜250 mm, the width of the lower portion connected to the cathode carbon block base is 200˜300 mm, the height of the convex structure is 80˜160 mm, the height of the trapezoid at the lower portion is at least one third of the total height of the convex structure.
[0063] On the cathode carbon block closest to the aluminum outlet, the minimum distance between the horizontal convex structure, near the aluminum outlet and disposed in the center of the cathode carbon block, and the outer lateral surface of the cathode carbon block base is 200˜300 mm; wherein the outer lateral surface of the cathode carbon block base is defined as the lateral surface of the cathode carbon block that faces the cell lining of the aluminum outlet.
[0064] An alumina electrolyte sludge groove is installed on top of carbon ramming paste 6 installed between the adjacent cathode carbon block bases, the depth of the sludge groove is 30˜60 mm, the width thereof is 80˜120 mm, the length thereof penetrates through the gap defined between the adjacent cathode carbon blocks. During the electrolytic production, the alumina electrolyte is filled in the sludge groove.
[0065] The operation method of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations is the same as the operation method disclosed in the first embodiment.
Third Embodiment
[0066] The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of this invention is shown in FIG. 5 and FIG. 6 . The whole structure of the electrolytic cell is the same as the electrolytic cell disclosed in the first embodiment, the difference is that convex structures are mixedly arranged. Horizontal convex structures and vertical convex structures are staggered on each cathode carbon block base. The quantity of horizontal convex structure is three, the length thereof is the same as the width of the cathode carbon block base. The length of vertical convex structure is defined with respect to four vertical convex structures aligned on each cathode carbon block base. On a cathode carbon block, the distance between two ends of the cathode carbon block and the bottoms of the vertical convex structures arranged at the two ends is 30˜50 mm. Wherein on the same cathode carbon block, the distance between the adjacent convex structures is 30˜400 mm.
[0067] FIG. 13 shows the cross sectional view of the vertical convex structure of the cathode carbon block 4 . FIG. 11 shows the cross sectional view of the horizontal convex structure. The cross section of the convex structure is in a trapezoidal shape, the width of top surface of each convex structure is 150˜250 mm, the width of the lower portion connected to the cathode carbon block base is 200˜300 mm, the height of the convex structure is 80˜160 mm. The width of the top surface of the horizontal convex structure disposed at the center of the cathode carbon block is 150˜200 mm.
[0068] On the cathode carbon block closest to the aluminum outlet, the minimum distance between the horizontal convex structure, near the aluminum outlet and disposed in the center of the cathode carbon block, and the outer lateral surface of the cathode carbon block base is 200˜300 mm; wherein the outer lateral surface of the cathode carbon block base is defined as the lateral surface of the cathode carbon block that faces the cell lining of the aluminum outlet.
[0069] An alumina electrolyte sludge groove is installed on top of carbon ramming paste 6 installed between the adjacent cathode carbon block bases, the depth of the sludge groove is 30˜60 mm, the width thereof is 80˜120 mm, the length thereof penetrates through the gap defined between the adjacent cathode carbon blocks. During the electrolytic production, the alumina electrolyte is filled in the sludge groove.
[0070] The operation method of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations is the same as the operation method disclosed in the first embodiment.
Fourth Embodiment
[0071] The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of this invention is shown in FIG. 7 and FIG. 8 . The whole structure of the electrolytic cell is the same as the electrolytic cell disclosed in the first embodiment, the difference is that convex structures are vertical convex structures, and the vertical convex structures are installed at the center of the top surface of the cathode carbon block base. The quantity of vertical convex structures is two. The distance between two ends of the cathode carbon block and the bottoms of the vertical convex structures arranged at the two ends is 30˜50m. On the same cathode carbon block, the distance between the adjacent vertical convex structures is 100˜200 mm.
[0072] FIG. 14 shows the cross sectional view of the vertical convex structure. The cross section of the convex structure is in a mixed shape of rectangle and trapezoid, the width of the top surface of convex structure is 150˜250 mm, the width of the lower portion connected to the cathode carbon block base is 200˜300 mm, the height of the convex structure is 80˜160 mm, the height of the trapezoid at the lower portion is at least one third of the total height of the convex structure.
[0073] The vertical convex structures are disposed at two ends with respect to the center of the cathode carbon block base. The gap defined between the two vertical convex structures directly faces the aluminum outlet.
[0074] An alumina electrolyte sludge groove is installed on top of carbon ramming paste 6 installed between the adjacent cathode carbon block bases, the depth of the sludge groove is 30˜60 mm, the width thereof is 80˜120 mm, the length thereof penetrates through the gap defined between the adjacent cathode carbon blocks. During the electrolytic production, the alumina electrolyte is filled in the sludge groove.
[0075] The operation method of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations is the same as the operation method disclosed in the first embodiment.
Fifth Embodiment
[0076] The aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations of this invention is shown in FIG. 9 and FIG. 10 . The whole structure of the electrolytic cell is the same as the electrolytic cell disclosed in the first embodiment, the difference is that convex structures are mixedly arranged, wherein the quantity of horizontal convex structure is one, the length thereof is the same as the width of the cathode carbon block base. The length of vertical convex structure is defined with respect to four vertical convex structures arranged as two rows on each cathode carbon block. Every two vertical convex structures arranged at the same row is defined as one set, thus there are two defined sets of vertical convex structure, and each set of vertical convex structure is staggered with one horizontal convex structure.
[0077] There are five convex structures installed on each cathode carbon block base. The distance between two ends of the cathode carbon blocks and the bottoms of the vertical convex structures arranged at the two ends is 30˜50 mm. The distance between the horizontal convex structure and each set of vertical convex structure is 30˜100 mm.
[0078] The convex structure at the center of the cathode carbon block is the horizontal convex structure. The minimum distance between the horizontal convex structure, near the aluminum outlet and disposed in the center of the cathode carbon block, and the outer lateral surface of the cathode carbon block base is 200˜300 mm; wherein the outer lateral surface of the cathode carbon block base is defined as the lateral surface of the cathode carbon block that faces the cell lining of the aluminum outlet.
[0079] FIG. 16 shows the cross sectional view of the vertical convex structure of the cathode carbon block. FIG. 12 shows the cross sectional view of the horizontal convex structure. The cross section of the convex structure is in a mixed shape of rectangle and trapezoid, the width of top surface of the vertical convex structure is 80˜120 mm, the width of top surface of the horizontal convex structure is 150˜200 mm, the height of the vertical and horizontal convex structures is 80˜160 mm, the distance between each set of vertical convex structure is 30˜100 mm, the height of the trapezoidal at the lower portion is at least one third of the total height of the convex structure.
[0080] The operation method of the aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations is the same as the operation method disclosed in the first embodiment.
[0081] Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.
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An aluminum electrolytic cell with a new type of cathode structure for shortening vertical fluctuations and horizontal fluctuations includes an electrolytic cell shell, cell lining, refractory material, cathode carbon blocks, lined carbon bricks, carbon ramming paste, refractory concrete and cathode steel bars. More than one convex structure protrudes from the top surface of the cathode carbon blocks and integrates with the cathode carbon blocks. The convex structure are arrayed to be parallel or vertical with the axis of the cathode carbon blocks or to be mixed with the above two.
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RELATED APPLICATION
This application claims priority from co-pending provisional applications Ser. Nos. 60/405,040 and 60/405,041, which were filed on Aug. 21, 2002, and which are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to the field of tissue engineering and, more particularly, to a modular bioreactor system which integrates cell seeding and cell culture, and associated methods.
BACKGROUND OF THE INVENTION
Engineered tissues, especially human tissues, offer great hope for treatment of a variety of diseases and for repair of damage to natural tissues due to trauma. Adults produce about 400 billion cycling cells daily, and loss of production of these cells is life threatening. In treating cancer patients, chemotherapy and radiation are commonly used; however, high-dose toxic drugs and irradiation not only kill cancer cells but also healthy hematopoietic cells produced by human bone marrow. Red blood cell and platelet transfusion and hematopoietic stem cell and progenitor cell (HSC/HPC) infusion are two commonly used clinical methods to replace mature blood cells and to reconstitute the blood-producing capacity of the patient. However, allogeneic matched donors are difficult to find and autologous HSC/HPC may be contraindicated or limited. Cord blood (CB) cells are obtained from umbilical cord of newborn babies and are rich in CD34+ cells and easy to procure. The challenge is to expand CB cells to large enough quantities for adult patients or for repeated transplant. Attempted improvements to ex vivo expansion methodologies have included the use of exogenous cytokines or growth factors or altering culture parameters such as culture duration and feeding schedules, which influence the differentiation and self-renewal of HSC/HPC. The ideas of these studies were to mimic the key elements of in vivo hematopoiesis environment, including soluble factors (e.g., cytokines), support cells and adhesion molecules, and physiochemical parameters.
However, to date, the field of hematotherapy has not extensively examined the effects of three-dimensional (3-D) geometry of the in vivo HSC/HPC environment and has failed to replicate the 3-D geometry in the ex vivo expansion systems. It is well established that cellular activities, including migration, proliferation, differentiation, and tissue functions, are significantly affected by cellular organization and structural cues both in vivo and in ex vivo cultures. Based on this knowledge, we have developed a 3-D small-scale culture system for ex vivo growth of HSC/HPC using a polyethylene terephthalate (PET) non-woven matrix. Our preliminary data show a substantial advantage for growth of CD34+ positive cells and committed colony forming units (CFU) in this 3-D matrix compared to standard two-dimensional control cultures. To successfully apply the 3-D culture system for clinical use, a perfusion bioreactor system is critically needed. The perfusion bioreactor system provides an environment for continuous nutrient delivery and waste removal, and thus sustains a high cell density in a 3-D matrix over an extended culture period. In addition, the perfusion bioreactor system can be automatically controlled and is less demanding for operation and culture handling, an important requirement for clinical use.
Also of interest are the cells in human bone marrow, as bone marrow contains hematopoietic tissue and the associated supporting stroma. While the hematopoietic stem cells produce mature blood cells, marrow stromal or stem cells (MSC) are the progenitor cells of skeletal tissue components and have the ability to differentiate into cell types phenotypically unrelated such as osteocytes, chondrocytes, muscle cells, adipocytes, and cardiomyocytes. Propelled by an increasing knowledge of human mesenchymal stromal cells (hMSC) biology, clinical evidence is emerging in the literature suggesting the tantalizing potential of hMSC for treating a wide range of diseases including osteogenesis imperfecta, tendon repair, stroke, and heart failure (8-11). For example, hMSC can be converted into myogenic progenitors in response to physiological stimuli, thus providing an alternative strategy for treatment of muscle dystrophies (3). In a recent study, researchers showed that injected bone marrow cells can form myocardial tissue and partially restored lost heart function in mice (24). To utilize hMSCs in clinical practice, a major obstacle, however, is to expand them to large quantity and yet retain their differentiation potential during the expansion.
The multi-potential properties of hMSC were first observed in the mid-1970s when whole bone marrow was grown in plastic culture dishes (18; 19). A small fraction of cells can be easily isolated by their adherence to the plastic surface after non-adherent blood cells were poured off. These adherent cells exhibited heterogeneous appearance and possessed striking features of self-renewal and differentiation even after 20 to 30 cell doublings (20). Recently, a more homogeneous (98% at passage 2) population of human MSC was obtained from bone marrow by using a density gradient to eliminate unwanted cell types (2). The cell population was expanded extensively on plastic culture dish and it maintained the ability to differentiate into multiple cell types in vitro, including adipogenic, chondrogenic, and osteogenic lineages (2). In a detailed study on purified hMSC growth kinetics, selfrenewal, and the osteogenic differentiation, hMSC was expanded for over 1.2×109 folds for 10 passages and maintained osteogenic differentiation capacity (4). However, a gradual increasing replicative senescence determined by the loss of population doubling potential after the first passage was observed. A recent study also reported a diminishing proliferation rate and a gradual loss of hMSC's differentiation capacity. The average doubling time increased from 1.3 for fresh bone marrow to 7.7 at passage 1 and up to 15.8 at passage 5, whereas adipogenesis started fading by 18 doublings and is totally lost by 22 passages (13). Studies have found that seeding density has profound effects on the growth rate of plastic-adherent cells from human bone marrow (12; 23). When the purified hMSCs were plated at low densities of 1.5 to 3.0 cells/cm2, they generated single-cell derived colonies and amplified about 109-fold in 6 wk (12). These single-cell-derived colonies contained three morphologically distinct cell types: spindle-shaped cells, large flat cells, and very small round cells, suggesting a heterogeneous cell population (12; 23). Compared to large cells, small round cells have greater rate of replication and enhanced potential for multi-lineage differentiation (23). The heterogeneous cell population and sensitivity to plating density were also observed for rat marrow stromal cells (14). Cell growth sensitivity to plating density may be explained by cell—cell contact and low seeding density appears to greatly enhance hMSC self-renewal and retain differentiation potential.
However, prior protocols used in obtaining and expanding hMSC require frequent cell passages and very large surface area for cells to grow. They are not designed for ex vivo expanding a large quantity of hMSC for clinical use. The 3-D feature, which is characteristic for hMSC in vivo environment, is also missing in the preparation. Many clinical cases require the reconstruction of a functional tissue in vitro before being transplanted to replace the damaged one. This becomes especially critical when the defect is larger than those that would spontaneously heal such as a large area of skin and a large bone defect, or when the immediumte replacement of tissue function is needed such as the replacement of cardiac muscle function. In these cases, a large number of cells alone are not sufficient; the cell must also exhibit desired functions or can be induced into a functional state once placed in the injury site. To achieve this, 3-D culture systems offer many advantages over conventional 2-D culture systems. A 3-D matrix offers a high surface area per unit volume and captures the 3-D feature of the in vivo tissue. Matrices that offer a 3-D structure have been widely used for tissue engineering a wide variety of tissues and for ex vivo expanding human hematopoietic progenitors (25-36). Among the materials used in these studies, non-woven fibrous matrix offers unique advantages. The non-woven fibrous matrix has isotropic structure, e.g., it has the same properties at three coordinates. In these matrices, regardless of where a cell lands, there will be the same amount of surface area available to it and it would have the same opportunity to interact with other cells. It also provides an environment where cells will have intimate interactions with neighboring cells and ECM network, which is a defining feature of in vivo tissue.
Three-dimensional matrices such as collagen gels, porous gelatin sponges, porous hydroxyapatite ceramic carrier, and a composite of hydroxyaptite/tricalcium phosphate (HA/TCP) particles have been previously investigated for cartilage and bone regeneration from hMSC (37-40). Particle size and shape, seeding density, and contraction kinetics influenced the growth and secretion of ECM proteins by hMSC. In these studies, hMSCs were first expanded in culture and then loaded onto the matrices. The end results were evaluated based on the performance after implantation. Despite the successes, a number of questions remain to be answered. The ex vivo expansion of hMSC is not carried out on these matrices. It also lacks the detailed information on how hMSCs adhere to the surfaces of the scaffolds and how the structures of the scaffolds affect their proliferation. A single device combining hMSC isolation, adhesion, expansion, and modularity will be of great advantage in simplifying the operation, especially in clinical use. In addition, hMSC grown at high density in a 3-D matrix may be directly induced to differentiate into desired functional tissues and be used in repairing large wounds. The critical requirements for the 3-D expansion system are high yield for hMSC isolation, high expansion rate, maintenance of primitiveness, and formation of desired tissue structure. For clinical use, the system should meet these requirements in one single unit.
SUMMARY OF THE INVENTION
With the foregoing in mind, the present invention advantageously provides a modular cell culture bioreactor apparatus for ex vivo expansion of HSC/HPC from cord blood and bone marrow samples. A three-dimensional (3-D) perfusion bioreactor system having a plurality of cell culture chambers comrprising nonwoven PET matrices is described for ex vivo HSC/HPC expansion. Operational parameters of the 3-D perfusion bioreactor system for dynamic cell seeding and harvesting have been determined. Preferred conditions are indicated for operation of the apparatus for ex vivo HSC/HPC expansion.
Accordingly, the invention includes a modular cell culture bioreactor apparatus. The apparatus comprises a plurality of chambers for cell culture; at least one reservoir containing a cell support medium; a plurality of conduits fluidly connecting the at least one reservoir with the plurality of chambers; and at least one pump fluidly connected through the plurality of conduits with the at least one reservoir and with the plurality of chambers to pump cell support medium therethrough. Each individual chamber of the plurality of chambers includes at least one three-dimensional matrix comprising polyethylene terephthalate, a plurality of channels carrying the cell support medium and having the matrix positioned in fluid communication therebetween, and at least two openings into each the channel, wherein a first the opening is in fluid connection with the pump and a second the opening is in fluid connection with the reservoir. The bioreactor apparatus is termed modular since the cell culture chambers are connected therein in parallel and each individual cell culture chamber may be independently disconnected from the apparatus while the apparatus continues to run with the remaining chambers in place.
In a preferred apparatus, the bioreactor matrix further comprises a nonwoven fibrous matrix of polyethylene terephthalate having a random microscopic structure. The matrix may have a thickness ranging from approximately 0.5 mm to 2.0 mm, and a a void to total volume ratio greater than approximately 0.8.
In use, the bioreactor apparatus includes cell support medium having an oxygen tension ranging approximately from 1% up to 20%. At least one pump generates a cell support medium flow rate of at least approximately 0.4 ml per minute through the bioreactor, the cell medium having a pH ranging approximately from 7.0 to 7.4.
Additionally, each individual chamber of the plurality of chambers comprises a valve positioned to control fluid flow through each the opening into each channel. More specifically, each individual chamber of the plurality of chambers comprises a valve positioned to shut off fluid flow to each the opening into each channel so as to permit each individual chamber to be disconnected and removed from the bioreactor apparatus. It should also be understood that the bioreactor apparatus further comprises means for maintaining a temperature effective for cell culture. The temperature maintaining means includes an incubator in which the entire apparatus is situated, or a temperature-controlled room, for example. Also, to maintain proper incubation temperature, each individual chamber of the plurality of chambers further comprises a water jacket along an outer periphery of the chamber, the water jacket in fluid connection with a water reservoir having a heater associated therewith for maintaining the water at a temperature effective for cell culture. In the apparatus, each individual chamber of the plurality of chambers may also further comprise a jacket along an outer periphery of the chamber, the jacket circulating a heat transfer fluid around the chamber.
A method aspect of the invention includesfiltering a medium carrying an inoculum containing cells through a three-dimensional matrix containing polyethylene terephthalate, wherein filtering is accomplished at a flow rate effective for permitting adherence to the matrix by predetermined cells; and diverting the course of the flow after filtering so that the medium flows essentially along peripheries of the three-dimensional matrix. In the method, the inoculum may consist of a sample of human bone marrow, or may contain human mesenchymal stromal cells, or human hematopoietic stem cells. In the method filtering and diverting are carried out within a single cell culture chamber, may be carried out substantially simultaneously in a plurality of cell culture chambers, and may be carried out without handling the matrix.
The method may additionally comprise monitoring cell count in the filtered medium as an indicator of cell adherence to the matrix and continuing filtration until a predetermined proportion of cells has adhered, and diverting the course of the flow after filtering so that the medium flows essentially along peripheries of the three-dimensional matrix.
BRIEF DESCRIPTION OF THE DRAWINGS
Some of the features, advantages, and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, presented for solely for exemplary purposes and not with intent to limit the invention thereto, and in which:
FIGS. 1 (A) and (B) show culture output in two-dimensional and three-dimensional cord blood cultures in presense or absence of serum;
FIG. 2 illustrates a bioreactor apparatus according to an embodiment of the present invention;
FIG. 3 also shows another embodiment of a bioreactor apparatus according to an embodiment of the present invention;
FIG. 4 shows a comparison of cell growth on a three-dimensional matrix following cell seeding by static and dynamic methods;
FIG. 5 shows (A) PI staining of the 6th slice of a total 10 slices; (B) p27-FITC staining of the same image; (C) PI staining of the 6th slice of a total of 9 slices; and (D) BrdU-FITC staining of the same image;
FIG. 6 shows stimulation of high estradiol secretion, p27 expression, and reduced cyclin B1 by human trophoblasts grown in the bioreactor with O 2 increased from 2% to 20% at day 3;
FIG. 7 is a flow diagram of a bioreactor apparatus according to the present invention, showing the valves and ports employed in the apparatus;
FIG. 8 shows a graph illustrating removal of seeded cells by the bioreactor matrix during consecutive passes through the matrix;
FIG. 9 is a bar graph showing the distribution of cells seeded into a bioreactor chamber in the apparatus of FIG. 6 , wherein each bioreactor has three matrices, as shown;
FIG. 10 shows a bar graph depicting distribution of seeded cells onto matrices 1, 2 and 3 during four consecutive passes of a seed cell inoculum in the apparatus of FIG. 6 ;
FIG. 11 is a line graph showing typical oxygen consumption of human mesenchymal stromal cells in a bioreactor at ambient O 2 tension;
FIG. 12 is a line graph showing glucose and lactate levels at bioreactor chamber inlet and outlet as measures of cell metabolism in the apparatus of FIG. 6 ; and
FIG. 13 shows bioreactor chamber inlet and outlet levels of lactic acid dehydrogenase (LDH) during cell culture in the apparatus of FIG. 6 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
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. Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including any definitions, will control. In addition, the materials, methods and examples given are illustrative in nature only and not intended to be limiting. Accordingly, this invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein. Rather, these illustrated embodiments are provided solely for exemplary purposes so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.
Ex Vivo Expansion of Human Hematopoietic Cells from Cord Blood.
A non-woven matrix of polyethylene terephthalate (PET) for tissue engineering differs from other porous medium in that a fibrous PET matrix has a high porosity (void to total volume ratio), usually larger than 85%, and high surface area per unit volume. These structural features provide a matrix having a large surface area for cell adherence and yet porous enough to facilitate nutrient transport to the cells grown in the matrix. PET, also known as Dacron, has been approved for medical use and has been commonly used in vascular surgery. It shows good biocompatability when used in culturing hematopoietic cells. PET matrices for use herein were prepared according to our previously developed thermal compression technique and modification of the spatial structure, e.g., porosity and pore size, of the non-woven matrices (Li Y, Ma T, Yang ST, Kniss DA. Modification and characterization of PET non-woven fibrous matrix as cell culture scaffold. Biomaterials 2001; 22:609-18). We have also quantified the matrix structure using a liquid extrusion method, as known in the art, which gives precise information on the effective pore radius and pore size distribution in the matrix. Using these techniques, PET fibrous matrices have been formed having porosities of 0.849, 0.895, and 0.926. The thickness of these matrices is also controlled, ranging from 0.5 mm to 2.0 mm.
It is known that there is a close correlation between the matrix structure and tissue development pattern. Using a dual-wave length staining technique and confocal microscopy, we have been able to quantify the 3-D structure of cell growth and to localize the cells at different cell cycle stages. Utilizing different cellular markers, we have analyzed the cell micro environment and established the correlation between the spatial position of an individual cell and its cell cycle phase. Using these techniques, we have been able to improve the structure of the 3-D scaffold according to the specific needs of a culture system. The hematopoietic microenvironment composed of nonwoven matrix and human cord blood (CB) cells is thought to mimic the marrow microenvironment and to help expand cord hematopoietic stem cells and prgenitor cells (HSC/HPC). The nonwoven PET fabric used herein has a relatively defined microstructure as the 3-D scaffold and was treated by hydrolysis so that its surface improved in cell adhesion. Different cell organizations formed in 3-D matrix in a developmental manner, from individual cells and cells bridging between fibers to large cell aggregates. Both stromal and hematopoietic cells were spatially distributed within the scaffold. Culture in this 3-D nonwoven matrix enhanced intimate cell—cell and cell-matrix interactions and allowed 3-D distribution of stromal and hematopoietic cells.
The formation of cell aggregates and higher progenitor content indicated that the spatial microenvironment in the 3-D culture played an important role in promoting hematopoiesis. Compared to two-dimensional CD34+ cell culture, 3-D culture produced 30-100% higher total cells and progenitors without added cytokines in a serum-containing system (FIG. 1 ). With thrombopoietin and fit-3/flk-2 ligand, it supported 2-3 fold higher total cell number (62.1 vs. 24.6 fold), CD34+ cell number (6.8 vs. 2.8 fold) and CFU number for 7-9 weeks (N=6), indicating a hematopoiesis pathway that promoted progenitor production (FIG. 1 ). These early static culture studies suggest that 3-D culture system can be used as an in vitro model to study stem cell or progenitor behavior, and to achieve sustained HSC/HPC expansion.
Perfusion Bioreactor Apparatus for Tissue Engineering
The bioreactor apparatus supports long-term 3-D tissue development because it ensures the nutrient delivery to and waste removal from the neotissue grown at high cell density in the 3-D matrix. We have successfully grown trophoblast cells in the 3-D perfusion bioreactor apparatus for up to one month with periodic medium changes and sampling. Collateral techniques facilitating reactor assembly and sterilization, control, and sampling are known in the art.
FIG. 2 shows an embodiment of the present bioreactor apparatus for human tissue engineering. A nonwoven PET matrix with cells was placed in a glass cyclinder and perfused by medium. (B). Two bioreactor chambers were connected in parallel to provide multiple data points. Another embodiment of the present bioreactor apparatus is shown in FIG. 3 , including a medium container, a medium reservoir, and a medium-circulating pump. The PET matrix is preferably fixed in a Teflon ring having, for example, a diameter of 3 cm, and a thickness of 1.0 mm, and placed in the middle of a cone-shaped glass vessel. The cone shaped vessel used herein has a bottom diameter of 2 cm, a top diameter of 4 cm, and a height of 6 cm. A reservoir holds the medium and gravitational force will cause the medium to flow through and perfuse the matrix. Non-adherent cells settle at the bottom of the bioreactor vessel and are collected. Spent medium will be transported to a medium container. A pump may be used to transfer medium from the medium container to the medium reservoir. In the medium reservoir, filter-sterilized air and CO2 gas will flow through the reservoir to provide O2 and to control pH in the range of 7.0 to 7.4. A magnetic stirrer and stirring bar may be employed to agitate the medium and to ensure a sufficient oxygenation.
Both of these embodiments integrate dynamic seeding and culturing of cells in the same device. It is important to note that the bioreactor apparatus of the present invention includes two or more cell culture chambers connected in parallel, so that each individual chamber may be disconnected from the bioreactor apparatus as necessary, while the bioreactor continues to operate with its remaining chambers.
The present bioreactor apparatus, a perfusion device, may be fabricated based on previously known bioreactors but with some improvements, for example, as shown in FIG. 4 . The PET matrix may be sandwiched between two surgical stainless steel plates (W=2.0 cm; L=8 cm) and placed it in the middle of a class cylinder (D=2.3 cm and L=8.5 cm). The matrix will separate the glass cylinder into two compartments with approximately equal volumes. A reservoir holds a cell support medium, and gravitational force may drive the medium flow through the cylinder and perfuse the matrix; alternatively, a pump may be employed for generating a flow of medium. Spent medium will be collected in a cell-liquid separator and non-adherent cells will also be collected. A pump may then transfer medium from the cell-liquid separator to the medium reservoir. In the medium reservoir, filter-sterilized air and CO2 gas preferably flow through the reservoir to provide oxygen and to control pH in the range of 7.0 to 7.4. A magnetic stirrer may be employed to agitate the medium and to ensure a sufficient oxygenation.
Preferred nonwoven PET matrices are used as the 3-D cell culture scaffold, and have the physical parameters of the matrices shown in Table 1. The PET matrices are washed with a scouring solution (1% Na2CO3, 1% v/v Tween.20) and are then treated by boiling in a 1% NaOH solution for one hour. This hydrolysis step reduces surface hydrophobicity, creating carboxyl and hydroxyl groups on fiber surfaces to enhance cell adhesion. The treated matrices are then compressed at approximately 4.5 psi at 121° C. for about 90 min to permanently reduce them to a desired thickness and to reduce the porosity and pore sizes. The compressed matrices are then cut into small portions of approximately 2.0 cm wide by 8.0 cm long, and sandwiched between two surgical stainless steel plates. The skilled will readily understand that these dimensions are provided as one example of preferred embodiments of the invention but may be varied to suit the specific application. Before being used for cell culture, the materials are washed extensively with tap water, deionized water and ultra-purified deionized water. Prior to addition of medium, the bioreactor apparatus is assembled and sterilized by appropriate autoclaving.
Given the number of cells available from cord blood (CB) units, the cell number available for expansion may be as low as 75×10 6 cells, and as high as 600×10 6 . We have examined inoculation densities ranging from 0.5 to 4×10 5 cells per cm 2 in two-dimensional systems. Optimal cell expansion was observed at concentrations between 2 and 4×10 5 cells per cm 2 in a 6-well plate without 3-D matrices. Based on its physical parameters, the addition of a 3-D matrix increases the available surface area by approximately 20-fold. The total matrix volume is about 1.5 cm 3 and the corresponding surface area is about 450 cm 2 , so that inoculation densities in the range of 2.0-4.0×10 5 cells/cm 2 were used in this study.
TABLE I Physical parameters of 3-D nonwoven matrices Property 3-D matrix Property 3-D matrix Fiber diameter 20 pm Porosity 0.849 ± 0.004 Fiber density 1.35 glcm 3 Pore size range 10_60 lm Specific surface area 278 ± 8 cm/cm 2 Average pore 30 gm diameter
Dynamic Cell Seeding and Harvesting in the Bioreactor Apparatus.
Cell seeding is the first step of operation and plays an important role in dictating initial seeded cell number, initial cell spatial distribution, and subsequent cellular processes for cell expansion. Efficient cell seeding will greatly reduce the time required for system operation and an even cell distribution in the matrix will greatly enhance the use of the 3-D matrix and improve the growth conditions. High seeding numbers can improve cell growth, and lower numbers often lead to a lower cell proliferation rate.
The present invention provides a dynamic seeding process to improve cellularity and cell distribution in the 3-D fibrous matrices. First, the wettability of the fibrous matrix is improved by hydrolyzation, as noted above. Additionally, hydrolyzation, matrix porosity, and precoating with serum-containing medium are used to improve medium penetration into the matrix.
In static seeding, a cord blood cell suspension may be used as the seeding inoculum. The inoculum is added by injecting the cell suspension into the medium, wherefrom cells will gradually settle onto the matrix by gravity. Dynamic seeding, however, employs a flow of medium to carry the suspended cells into the matrix, conditions for dynamic seeding being determined for each bioreactor apparatus by changing the concentration of cell suspension, medium flow rate, and duration of the injection. Initially, a concentration of cells in suspension is used in approximately the range of 1.0×10 5 -5.0×10 6 cells/ml. The desired seeding concentration is then determined based on achieved seeding efficiency and cell expansion.
From previous studies, FIG. 4 shows that dynamic depth filtration seeding produces a high density and fairly uniform cell distribution pattern in both the central region (A) and near the perimeter (C) of the matrix. Static seeding, on the other hand, produced a non-uniform cell distribution with a low cell density in the central region (B), but more cells in the perimeter area of the matrix (D).
In harvesting the expanded cell population from the bioreactor, concern for maintaining cell surface markers has led to the use of a cell dissociation solution (CDS), which is an EDTA based non-enzymatic technique for harvesting cultures. Unlike cells grown on a 2-D plastic surface, the use of such a cell harvesting reagent alone may not be sufficient to remove cells from the 3-D PET matrix. It is important to adjust harvesting techniques to improve cell recovery. This has been explored by comparing results from experiments using 0.05% trypsin and EDTA side-by-side. After culturing, non-adherent cells are collected by perfusing the matrix with phosphate buffered saline (PBS). This non-adherent fraction is counted separately from the adherent fraction. Adherent cells are harvested either by incubating the matrices for 7 minutes at 37° C. with 0.05% trypsin, or by incubating matrices with CDS (Sigma). The removed adherent cells are then collected and rinsed once more with medium. These techniques reproducibly results high viable cell recovery. Any cells remaining in the matrix after non-adherent and adherent cell removal are visualized by staining and examined using either confocal microscopy, or paraffin embedded sections. Whether harvesting under flow conditions will enhance cell recovery from the 3-D matrix was investigated by perfusing the bioreactor with cell harvesting reagents under flow rates ranging from 0.5-3.0 ml/min. Efficiency of cell harvesting by perfusion was evaluated as noted above for the other techniques.
HSC/HPC Ex Vivo Expansion in 3-D Perfusion Bioreactor Apparatus.
Cord blood mononuclear cells were purchased from Clonetics, Walkersville, Md. The bioreactor apparatus is assembled and operated without cells for about ten to twelve hours, although the exact timing may be varied according to need. The bioreactor is then seeded according to the methods described above. Significant benefits in hematopoietic cell output are detectable after 21 days of culture. In a clinical setting, however, longer culture periods may not be suitable waiting periods for patients. Thus, we have examined culture output at days 6, 12, 18 and 24. Human long term culture medium MyeloCult® H5100 (StemCell Technologies Inc., Vancouver, Canada) is used supplemented with serum. Approximately 300 mlof medium is employed for an initial culture period. After three days, about 100 mL of medium is exchanged with new medium and the spent medium is monitored for glucose and lactate concentrations. At days 6, 12, 18, 24, the cells grown in the matrix are sacrificed to determine cell number and cell morphology. The matrices are washed twice with PBS and those cells dislodged will be considered non-adherent cells. The cell-containing matrix is cut into two pieces having approximately equal area. Cell dissociation solution (CDS, Sigma-Aldrich Co.) is then used to harvest adherent cells from the matrix and to minimize alteration of cell surface characteristics. The cellular samples are then evaluated by scanning electronic microscopy (SEM), hematoxylin and eosin (H&E) staining, and immunocytochemistry analysis using confocal laser microscopy (CLSM), flow cytometry, and colony-forming unit assay. Non-adherent and adherent cells will be mixed together for cell counting and assay of colony-forming units. Results from these assays will provide the kinetics of long-term CB expansion (cell counting and CFU assay), metabolic activities (lactate and glucose), cell morphology (Wright's stain and SEM), cell population distribution (flow cytometry), and organization of different types of cells grown in the matrix (immunocytochemistry staining using CLSM). Quantitative results are expressed as the mean±SD and statistical analysis was carried out using a commercial software package (Minitab® 11 for Windows, Minitab, Inc., State College, Pa.).
Ex Vivo Expansion Of Human Mesenchymal Stromal Cells
The isolation of hMSCs from blood cells was first conducted through adherence to the surface of plastic cultureware followed by non-adherent blood cells being poured off. To date, the strong adherence of hMSC to plastic surfaces remains one of the most effective methods for isolating hMSC from bone marrow cells. This isolation procedure, however, requires multiple washings and it takes several days to obtain a relatively pure hMSC population. Frequent handling of culture is laborious and prone to contamination.
The present invention discloses a depth-filtration method for hMSC seeding onto a 3-D PET matrix. The apparatus operates under periodic flow conditions to remove non-adherent cells and to provide nutrients needed for hMSC expansion. hMSC concentration in suspension and medium perfusion rate are controlled to allow sufficient contact time between hMSC and the PET matrices. A hydrolyzed PET surface has similar properties as plastic cultureware and facilitates hMSC adherence. The perfusion medium flow will not only carry the seed inoculum of hMSC but will also remove nonadherent cells. This depth filtration method is also effective for separating hMSC from human bone marrow mononuclear cells by applying a mixture of hMSC and mononuclear cells to the filtration device. After seeding, the subsequent culture is carried out in the same device without the need for handling the seeded matrix.
Cell Seeding by Depth Filtration.
Human mesenchymal stem cells (hMSC) were obtained from normal human bone marrow and hMSC growth medium was purchased from Clonetics, Inc. (Walkersville, Md.). The hMSC were expanded in a T-flask following the standard method provided by Clonetics, Inc. Briefly, cryovials containing hMSC are removed from liquid nitrogen storage and are thawed. The thawed hMSC are inoculated at a density of 5×10 3 cm 2 and incubated in a CO 2 incubator for three days before changing the medium. When the confluence of hMSC is about 80%, the cells are passed to four new T-flasks with approximately the same seeding density. After two passages, the cells are trypsinized and a cell suspension is prepared for seeding onto the PET matrix using the depth filtration method.
Nonwoven PET fibrous matrices are hydrolyzed using a 1 N NaOH solution and then cut into round shape patches with diameter of 3 cm and thickness in the range of 0.5 to 2.0 mm. Patches will be washed thoroughly with de-ionized water, autoclaved, and stacked up to three contiguous layers in the bioreactor. PET matrices having different porosities as shown in Table 2 were used. In previous studies, it has been shown that that the porosity of the matrix has a significant effect on cell seeding and growth.
Ave.
Specific
diam-
thick-
pore
Surface
Pore
Prop-
eter
ness
volume
poros-
diam
Area
size range
erty
(cm)
(mm)
(em 3 )
ity
(FAm)
(cm 2 /cm 3 )
(flon)
LP
3.00
1.00
0.7065
0.849
30
278
10-60
HP
3.00
1.00
0.7065
0.895
40
193
25-75
UP
3.00
1.00
0.7065
0.926
75
136
60-130
Table 2. Both LP (low porosity) and HP (high porosity) were prepared by thermally compressing low-porosity and high-porosity matrices, respectively. UP (unpressed) is the unpressed low-porosity matrix. These matrices had the same chemical properties but different porosities and pore size distributions.
Before seeding, medium is introduced into the bioreactor apparatus and is the matrix is incubated overnight, or approximately ten to twelve hours. A 20 ml aliquot of a cell suspension at a concentration of 5×10 5 cells/ml serves as seeding inoculum. A sterile syringe is used to inject and mix the cell suspension with the medium flow from the reservoir. A source of vacuum, possibly a second sterile syringe, is used to create negative pressure in the medium container. The flow rate of the cell-containing medium, the inoculum, passing through the PET matrix will be controlled at approximately 1 ml/min by adjusting the pressure difference. The cell concentration of the medium is controlled by adjusting the rate of injection of the concentrated cell suspension into the flow of medium. When hMSCs were expanded in T-flasks, a cell seeding density of 5×10 3 cells/cm 2 was recommended. For seeding, however, it is desirable to control the inoculation density in the range of 1×10 3 to 5×10 4 cells/cm 2 based on known specific surface area and volume of the PET patches (Table 2). The number of cells in the filtration effluent is counted to determine the efficiency of cell retention. Cells retained in the matrix are perfused using fresh medium for 30 minutes every 3 hours to remove non-adherent cells and to provide fresh medium for adherent cells. The system was operated for two days in this manner and the cells were counted in the medium washed out to determine if all the cells are firmly adhered to the surfaces of the matrix. The matrices were then removed from the bioreactor to determine cell morphology and cell organization therein. Cell number was determined using a DNA assay. Cells grown in the matrix were fixed and a scanning electron microscope (SEM) was employed to determine general cell morphology. The matrix with cells was also fixed with 70% ethanol and embedded in paraffin for histologic analysis.
HMSC Isolation from Bone Marrow.
The efficiency of depth filtration method to isolate hMSC directly from human bone marrow was tested. In a simulation, human bone marrow mononuclear cells were mixed with hMSCs in different. The same seeding procedure as described above was followed and non-adherent cells were collected when washed out by perfusion medium flow. Non-adherent cells were counted to determine the retention efficiency. After twenty four hours, the matrix was removed and a determination was made of the epitope profile of the adherent cells using the methods previously described.
Effects of Seeding Conditions and Matrix Porosity on hMSC Expansion.
In two-dimensional culture, it is known that hMSC tend to exhibit higher growth rates when plated under very low density, thus indicating that a large surface area is required to obtain a large quantity of cells. In addition, a gradually increasing loss in the doubling potential of the cell population after a first passage has been observed, suggesting that the multiple passages required in conventional culture in plastic cultureware may exert adverse effects on hMSC's expansion and multi-lineage potentials.
More importantly, successful closure of large wounds such as bone defects requires a large cellular replacement with desired functions. Thus, cultivation of hMSC in 3-D matrix is not only a novel approach for ex vivo hMSC expansion but also an effective means to produce functional tissue for transplantation. A nonwoven fibrous matrix has high specific surface area and is uniquely adapted to serve as a scaffold for hMSC expansion. In addition, it is possible to control the pore diameter of a non-woven PET matrix, ranging from 10-150 μm.
hMSCs were seeded into the bioreactor using the depth filtration method described above. The oxygen tension of the medium in the medium container was controlled at about 20% at a pH of 7.2 by adjusting the ratio of air to CO2. The periodic medium flow was induced for a half hour every 3 hours at about 1 ml/min. This periodic medium flow will not only deliver nutrients and remove the metabolites but will also remove non-adherent cells. Two bioreactor cell culture chambers were connected in the apparatus in parallel so that one may be removed for sampling without interrupting the operation of the entire apparatus.
Cell Number and Cell Cycle Analysis.
A DNA assay was used to determine total cell number for the cells grown in the matrix. After inoculation using the depth filtration method, the cells were cultured in the matrix for up to 30 days. Samples of matrices were taken using sterile technique at days 3, 5, 8, 12, 15, 30 and analyzed for DNA contents to determine cell number. Six matrices were employed for each data point. MSC cell cycle analysis was conducted by measuring DNA content by flow cytometry.
Human MSCs grown in the matrices with different inoculation densities were trypsinized, permeabilized with 70% ethanol (10 min at 4° C.), and labeled with 10 mg/ml PI (Sigma), followed by treatment with 0.1 mg/ml RNAse A. A FACScan flow cytometer is used to analyze DNA content and distribution in different cell cycle stages. This assay was performed at days 3, 8, 15, and 30, the results from this assay, cell proliferation kinetics, and cell spatial growth pattern providing detailed information on how different seeding conditions, matrix porosity, and cell organization affect hMSC growth.
Morphologv and Histological Analysis.
Scanning electron microscopy (SEM) was used to examine the morphology of the cells grown in the matrices at days 5, 12, and 30. The specimens were fixed with 1.6% glutaraldehyde in 0.1 mole/L cacodylate buffer for 24 hr immediumtely after removal of PBS solution and dehydrated in graded ethanol solution, followed by drying in a critical point dryer. After sputter coating with gold/palladium, the samples were examined in a JEOL JSM 840 SEM. The cells grown in the matrices were also fixed, embedded in paraffin, and observed in cross sections after H&E staining. Histological studies aid in determining cell distribution in the matrix.
Spatial Growth Pattern.
Spatial growth pattern of the cultured cells was determined by the distribution of cells at different cell cycle stages. This is important in elucidating the relationship between the cell cycle stage and its local environment. Immunocytochemical staining and confocal microscopy were employed to obtain images of the distribution of specific cell cycle markers. At days 3, 8, 15, and 30, the cell-containing matrices were incubated with 5-bromo-deoxyuridine (BrdU) containing medium (0.5 mM) for 4 hrs. As known by the skilled, BrdU is a thymidine analogue that can only be incorporated into the proliferating cells undergoing DNA synthesis (cells in S phase). Cells containing BrdU were then detected by a published immunocytochemistry method (Ma T, Li Y, Yang ST, Kniss DA Tissue engineering human placenta trophoblast cells in 3-D fibrous matrix: spatial effects on cell proliferation and function. Biotechnology Progress. Biotechnol Prog 1999; 15:715-24; and Ma T, Li Y, Yang ST, Kniss DA Effects of trophoblast cell organization in fibrous matrix on long-term tissue development and cell cycle. Biotech Biotechnol 2000; 70:606-18).
To determine the fractions of proliferating cells in the matrix, the entire cell-containing matrix was also counter-stained by propidium iodide (PI) after incubation with FITC-conjugated secondary antibody. PI is a nucleic acid dye that would stain all the cell nuclei regardless of the cell cycle stage (Id.). The cell images of the same sample obtained at these two different wavelengths allow one to identify proliferating and nonproliferating cells in the matrix. Negative controls were prepared for cultures grown without BrdU, following the same fixation procedures and stained with the secondary antibody only. Negative controls were also be prepared for cells only stained by PI, following the same fixation procedures. Also detected were the expression of p21°1P″, p27k1PI, cyclin B and cyclin D and determine the spatial SMC growth patterns following the above method without pre-incubation with BrdU. Propidium iodide counterstaining was performed when necessary.
FIG. 5 shows (A) PI staining of the 6th slice of a total 10 slices; (B) p27-FITC staining of the same image; (C) PI staining of the 6th slice of a total of 9 slices; and (D) BrdU-FITC staining of the same image. Note that most of the cells in the center of the aggregates are p27 positive, whereas BrdU incorporated cells are at the rim of the aggregate.
Epitope Profile.
The expression of specific cell surface markers for phenotypic characterization of MSC was also detected. Cells were detached with 0.07% EDTA, washed with PBS containing 2% FBS, and incubated with specific antibody at the concentration 1:100 to 1:1000, determined by titration. After incubation, cells were washed with blocking buffer and incubated with secondary antibody (FITC-conjugated mouse IgG). The antibodies used included CD34, CD45, CK18, CK19, VCAM-1, vWF, SH2, SH3, and SH4. CD34 and CD45 are hematopoietic cell markers and hMSCs are CD34 and CD45 negative. Previous studies have found that hMSC are positive for CK18, CK19, VCAM-1, vWF, SH2, SH3, and SH4 and these antibodies were used to determine the expressions of these markers by hMSC grown in the matrices on days 3, 8, 15, and 30.
Alkaline Phosphata e and Calcium Assay.
Detection of alkaline phosphatase activity on days 8, 15, and 30 was carried out. Briefly, triplicate cultures from each experiment were collected and 1 ml, of a 1 mg/ml solution of alkaline phosphatase substrate (p-nitrophenyl phosphate) in a buffer containing 50 mM glycine and 1 mM MgCl 2 ·6H2O will be added. After 10 minutes the solution is removed and mixed with 1 M NaOH solution. The solution is diluted, transferred to a 96-well plate and read at 405 nm using a microplate reader (Bio-Rad Laboratories, Hercules, Calif.). Calcium assay was performed on day 8, 15, and 30.
Cells grown in the matrices were rinsed with Tyrode salt buffer solution and fixed with 1% (v/v) glutaraldehyde in Tyrode's for 30 min. Samples are then rinsed with dionized water and allowed to dry. Calcium is extracted with 3 ml of 0.6 M HCl by immersing the matrix in the solution overnight while rocking. Periodic pipetting was applied when necessary. Aliquots were diluted and a commercial calcium assay kit was employed with the samples. The absorbance was read at 575 nm with a microplate reader (Bio-Rad Laboratories, Hercules, Calif.). The total amount of alkaline phosphatase and calcium was normalized by DNA content determined by DNA assay.
Effects of Oxygen Tension on hMSC Expansion in the Apparatus.
In vivo, oxygen tension of bone marrow is in the 27-49 mmHg range, corresponding to an O 2 concentration of approximately 4-7%. This value is significantly lower than what is used in standard CO 2 incubator where most previous hMSC experiments have been conducted. The perfusion bioreactor apparatus herein described was used to examine hMSC growth and differentiation under 1%, 2%, 5%, 10%, and 20% oxygen tension.
The same procedure described above was used to operate the bioreactor apparatus. After seeding, the O 2 tension of the medium was controlled by adjusting the ratio of O 2 N 2 , and air circulating in the medium container. The O 2 tension is detected by a dissolved oxygen (DO) probe, and controlled at the desired levels of 1%, 2%, 5%, 10%, and 20%. This is achieved by adjusting the flow rates of CO 2 , N 2 , and air, which are automatically controlled by the DO controller connected to the air, N 2 , and CO 2 pumps. The cellular and medium samples were collected at different time points to determine hMSC growth and differentiation under different O 2 tensions. Assays were conducted following the same procedures outlined above. As an example of the effect of O 2 on cell growth and differentiation, FIG. 6 shows stimulation of high estradiol secretion, p27 expression, and reduced cyclin B1 by human trophoblasts grown in the bioreactor with O 2 increased from 2% to 20% at day 3.
A DNA assay was used to determine total cell number for the cells grown in the matrix under 1%, 2%, 5%, 10%, and 20% O 2 . After inoculation using the depth filtration method, cell samples were collected on days 3, 5, 8, 12, 15, 30 and analyzed for DNA contents of the matrices to determine cell number. Three matrices were used for each data point. MSC cell cycle analysis was conducted by measuring DNA content by flow cytometry for each condition. Morphologv and histological analyses were conducted using scanning electron microscopy (SEM) to examine the morphology of the cells grown in the matrices at days 5, 12, and 30 under 1%, 2%, 5%, 10%, and 20% O 2 .
The same procedure outline above was used to determine spatial growth pattern by examining the distribution of cells grown under 1%, 2%, 5%, 10%, and 20% O 2 at different cell cycle stage.
Expression of specific cell surface makers was detected for phenotypic characterization of hMSCs grown under 1%, 2%, 5%, 10%, and 20% O 2 . Finally, alkaline phosphatase and calcium assays were conducted on days 8, 15, and 30 for hMSCs grown under 1%, 2%, 5%, 10%, and 20% O 2 .
Example of the Modular Cell Culture Bioreactor in Operation
FIGS. 7-13 illustrate a typical modular bioreactor apparatus according to the present invention, and various cell activity parameters associated therewith. FIG. 7 shows a flow diagram of a bioreactor apparatus according to the present invention, showing the valves and ports employed in the apparatus. It should be noted that each bioreactor cell culture chamber has three matrices therein. During dynamic seeding by depth filtration, only one inlet port is open, and only one outlet port is open but on an opposite side of the matrices from the open inlet port. This arrangement creates a flow of medium carrying cells from the open inlet port, through the matrices, and out the open outlet port. This dynamic cell seeding cycle may be repeated a number of times in order to allow a high proportion of the cells to adhere to a matrix. FIG. 8 , for example, shows a graph illustrating removal of seeded cells by a bioreactor matrix during consecutive passes through the matrix. FIG. 9 is a bar graph showing the distribution of cells seeded into a bioreactor chamber in the apparatus of FIG. 7 , wherein each bioreactor has three matrices, as shown. As the medium flow during seeding is essentially parallel through the three matrices, it appears that the matrices retain an approximately equal number of adhering cells regardless of whether the matrix is in position one, two or three in the bioreactor chamber. FIG. 10 shows a bar graph depicting distribution of seeded cells onto matrices 1, 2 and 3 during four consecutive passes of a seed cell inoculum in the apparatus of FIG. 7 , indicating the approximately equal distribution of cells.
Cell growth parameters in the apparatus of FIG. 7 are shown in FIGS. 11-13 . For example, FIG. 11 is a line graph showing typical oxygen consumption of human mesenchymal stromal cells in a bioreactor at ambient O 2 tension. FIG. 12 is a line graph showing glucose and lactate levels at bioreactor chamber inlet and outlet as measures of cell metabolism in the apparatus of FIG. 7 . Finally, FIG. 13 shows bioreactor chamber inlet and outlet levels of lactic acid dehydrogenase (LDH) during cell culture in the apparatus of FIG. 6 . These indicators point to healthy cell growth during operation of the modular apparatus described herein.
In the drawings and specification, there have been disclosed a typical preferred embodiment of the invention, and although specific terms are employed, the terms are used in a descriptive sense only and not for purposes of limitation. The invention has been described in considerable detail with specific reference to these illustrated embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification and as defined in the appended claims.
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An apparatus and method for a modular cell culture bioreactor comprises a plurality of chambers for cell culture; at least one reservoir containing a cell support medium; a plurality of conduits fluidly connecting the at least one reservoir with the plurality of chambers; and at least one pump fluidly connected through the plurality of conduits with the at least one reservoir and with the plurality of chambers to pump cell support medium therethrough; wherein each individual chamber of the plurality of chambers includes at least one three-dimensional matrix comprising polyethylene terephthalate, a plurality of channels carrying the cell support medium and having the matrix positioned in fluid communication therebetween, and at least two openings into each the channel, wherein a first the opening is in fluid connection with the pump and a second the opening is in fluid connection with the reservoir.
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BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to governors and more particularly to pneumatic speed regulators for variable speed engines.
(2) Description of the Prior Art
Adjustable flyweight governors for regulating the speed of large internal combustion engines or turbines are well known and have reached a high stage of development. A typical example of such would be a governor as manufactured for many years by Woodward Governor Company of Ft. Collins, Colorado. Basically, these governors rotate the flyweight from a drive shaft which is driven from the engine. (As used herein the term "engine" is meant to also include a variable speed turbine.) The position of a speeder plug against a speeder spring which bears against a thrust bearing on the toe of the flyweight will determine the speed of the engine. In operation, the thrust bearing will normally have a fixed position. Upward movement of the thrust bearing will indicate the speed of the engine is too fast and this upward movement will be translated to a valve which, through a hydraulic system, will decrease the fuel to the engine. A speed above the set speed will result in an opposite reaction.
The governors also have many additional adjustments and refinements not important here.
Therefore, the speed of the engine is actually controlled by the position of the speeder plug.
In many installations, satisfactory operation is obtained by manually setting the speeder plug for the desired speed.
However, in certain installations it is desired to automatically set the speed in the engine. E.g., in the operation of a compressor station, it is desirable to have the compressor and, thus, the engine operate at a speed responsive to the pressure of the incoming gas. I.e., the lower the gas pressure coming into this station, the slower the speed of the engine.
Before my invention, workers in the art would make the speed responsive to the external conditions (e.g., the pressure of the incoming gas at a pressure station) by attaching a pneumatic actuator externally of the governor by attaching the output of a pneumatic diaphragm to the arm on the speed adjustment shaft, which was linked to the speeder plug.
SUMMARY OF THE INVENTION
(1) New and Different Function
I have invented a more compact and responsive actuator for the governor. The diaphragm is directly connected to the speeder plug. By eliminating the speed adjust shaft with its seal problems and friction, the governor is made much more responsive to the incoming air signal which is used to regulate it. So the problems with friction and seals to keep dust and dirt out of the governor mechanism is eliminated. Furthermore, hysterisis and repeatability are greatly improved.
In addition to this, I have developed integrally with the diaphragm a two-spring system with a lost motion mechanism. By this arrangement, selective responses are made much better.
Thus, it may be seen that the function of the total arrangement far exceeds the sum of the functions of the individual elements of the springs, diaphragms, etc.
(2) Objects of this Invention
An object of this invention is to automatically adjust the governed speed of an engine.
Further objects are to achieve the above with a device that is sturdy, long lasting, compact, durable, lightweight, simple, safe, efficient, versatile, ecologically compatible, energy conserving, and reliable, yet inexpensive and easy to manufacture, install, adjust, operate and maintain.
Other objects are to achieve the above with a method that is versatile, ecologically compatible, energy conserving, rapid, efficient, and inexpensive, and does not require highly skilled people to install, adjust, operate, and maintain.
The specific nature of the invention, as well as other objects, uses, and advantages thereof, will clearly appear from the following description and from the accompanying drawing, the different views of which are not scale drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematical representation of the use of a governor having a novel speed adjust according to this invention in the environment of its use.
FIG. 2 is a sectional view of my invention attached to the ballhead assembly of the governor.
FIG. 3 is a chart showing the relationship between the speeder plug travel and the signal air pressure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there may be seen a typical installation as this invention would be used. Compressor 10 compresses gas from inlet pipe 12 to outlet pipe 14. The compressor 10 is driven from engine 16. The speed of the engine 16 is regulated by governor 18 according to the speed as set by the speed adjust mechanism 20. The speed adjust mechanism is responsive to the signal air pressure received from pressure sensor and transmittor 22.
In the typical installation as seen in FIG. 1, the lower the pressure in the inlet pipe 12, the slower it is desired to have the engine speed and therefore, the speed adjust would so regulate. I.e., the speed requirement of the load (compressor 10) is reflected by fluid pressure related thereto produced by sensor and transmitter 22 which is operatively associated with the load.
Referring to FIG. 2, there may be seen a portion of a governor 18. The ballhead 24 would be rotated through gear 26. The gear would be driven by a train of mechanism (not shown for clarity) from drive shaft 28 from the engine 16. The speed of rotation of the ballhead 24 will be directly proportional to the speed of the engine 16. Thus, the gear 26 is part of means for rotating the ballhead at a speed directly related to the engine speed. Flyweights 30 are pivoted to the ballhead 24. The toe 32 of each flyweight bears against thrust bearing 34. The speeder rod 36 is connected to the thrust bearing 34 and, therefore, any speed changes as determined by the mechanism are signalled to the engine through the speeder rod 36. The speeder rod 36 is a part of fuel feed means for regulating the fuel fed to the engine.
The speed of the engine is determined by the position of speeder plug 38. The lower the speeder plug 38 the more pressure will be exerted through speeder spring 40 onto the thrust bearing 34. With more pressure upon the thrust bearing the flyweights 30 must rotate faster to exert the counterbalancing centrifugal force. If the speeder plug 38 is raised above a predetermined position, the speeder plug will raise or lift up the thrust bearing 34 through shut down rod 42. This predetermined position is determined by the position of the shutdown nut 44, held in position by lock nut 46.
Those skilled in the governor arts will recognize that the detailed description to this point describes parts and elements which are old, well-known and commercially available upon the market.
Spring case or housing 48 is attached to the top of the governor housing 50 which contains the governor parts described above. Inasmuch as commercially available parts are used, an adapter 52 is used in making this transition or attachment.
Actuator rod 54 is securely attached and depends from diaphragm plate 56. The speeder coupler 58 is attached by suitable means to the top of speeder plug 38. Adjusting screw 60 is a part of the coupling and extends upward from the speeder coupler. The adjusting screw is threaded into the bottom of the actuator rod 54 and is held in adjusted position by lock nut 62.
Diaphragm 64 connects the diaphragm plate 56 to the spring housing 48. Diaphragm case 66 forms a chamber 68 between the diaphragm and diaphragm plate 56 at the diaphragm case 66. Nipple 70 forms a means for connecting control air pressure from the pressure sensor and transmitter into the chamber 68.
A plurality of helical compression low speed springs 72 extend between the bottom of diaphragm plate 56 and the top of spring seat 76. The exact positioning of spring seat 76 is adjusted by spring adjuster 78 which is a tube with external threads thereon. It may be seen that relative rotation of the spring seat 76 and ajuster 78 will determine the distance between the bottom of the diaphragm plate 56 and the top of the spring seat 76. A plurality of knobs 74 on the bottom of the plate 56 and the top of the seat 76 hold the helical compression springs 72 in position.
Stud 80 extends upward from the top of diaphragm plate 56 and as such forms an extension of the actuator rod 54. A seal is formed at the top of the diaphragm case 66 by bushing 82 with its associated O-rings. The bushing is held in place by bushing retainer 84 immediately above the diaphragm case 66.
Crosshead 86 is mounted for longitudinal vertical movement, relative to the stud 80 and upon the stud 80. Range adjusting screws 88 are attached for rotation into the crosshead. They are right and left hand screws. Lever elements 90 are mounted upon the adjusting screws 88.
Normal speed bow springs 92 are attached by nuts 94 to the bushing retainer 84. The levers 90 have alignment pins 96 depending from them which straddle the bow springs to hold the parts in position. Contact pins 98 upon the top and bottom of the levers transmit the force from the springs 92 to loading washer 100. Spherical washer 102 rides above loading washer 100 and it, like the crosshead, is mounted for vertical movement on the stud. Lock nuts 104 limit the travel of the spherical washer 102. The washers 100 and 102 are considered part of the crosshead assembly.
High speed adjustment nut 106 is threaded to the stud 80 and held in position by a suitable set screw. The bottom of the high speed adjustment nut will butt against the top of the bushing retainer 84 to limit the downward travel of the stud 80 and, thus, the actuator rod 54. As may be seen, this limits the downward travel of the speeder plug 38 and, therefore, limits the maximum speed of the engine 16.
Operation
To set the speed adjust mechanism for operation the following steps are followed. The spring adjust 78 is set to give a downward travel or position of the actuator rod 54 of 0.000 with a zero psi pneumatic signal. They are also set that the actuator rod 54 has a 0.115 inch (3 mm) travel at 3 psi (155 torr). In this setting the actuator is now set to follow the curve of point A to point B upon the graph seen in FIG. 3. The specific air pressures and speeder plug movements are not shown in the graph of FIG. 3 because it will be understood that those having ordinary skill in the art can adjust the movements and the pressures for any settings they desire. Also it will be understood that when it is stated that the actuator rod 54 will have a certain movement that the speeder plug 38 will have the same movement inasmuch as they are directly connected together. The operation from A to B is low speed operation and from B to C is normal speed operation.
With the 3 psi (155 torr) pneumatic signal, the actuator rod 54 is in the 0.115 inch (3 mm) travel position. The adjusting screw 60 is adjusted so there is enough speeder spring 40 deflection to balance the centrifugal force of the flyweights 30 which are being rotated by the ballhead 24. This adjustment of the adjustment screw 60 is made so that the engine will be operating at its desired minimum operating speed with the actuator rod 54 having the 0.115 inch (3 mm) position.
Also with the actuator rod 54 in the 0.115 (3 mm) travel position, the shutdown nut 44 and its lock nut 46 are adjusted on the shutdown rod 42 so that the bottom of the shutdown nut has 0.078 inch (2 mm) clearance between the top of the speeder plug 38 and the bottom of the nut. Thus, it may be seen when the pnuematic signal is dropped to 1 psi (50 torr) the parts in the actuator have moved upward and there is no longer any clearance in the top of the speeder plug 38 and the bottom of the shutdown nut 44. As the pneumatic signal to the activator is reduced, there is a positive lift on the speeder plug 38 which in turn lifts the shutdown rod 42 which in turn lifts the speeder rod 36. The lifting of the speeder rod 36 will in effect shutdown the engine 16.
Those having skill in the operation of engines using natural gas for fuel will understand certain problems, namely:
One, when starting the engine, as the engine starts turning over the governor will open to the maximum position. The governor will open the carburetor and mixing valves to the maximum position which may flood the engine before it starts or cause it to over speed or start-up since it is receiving maximum fuel.
Two, a natural gas engine is very unstable when unloaded. E.g., a twelve cylinder engine may be running unloaded and only three or four of its cylinders are at a normal operating temperature and, therefore, producing power. The governor will decrease fuel when a strong cylinder fires and increase fuel when a weak cylinder fires. This causes the governor to over correct giving a wild swing in engine speed.
Therefore, I provide the adjustment for the shutdown rod as set out above. In normal operation, the operator will send an artifical zero psi signal to the governor on start-up. The governor stays in the minimum position which holds the carburetor and mixing valves in the minimum fuel position to eliminate over fueling and flooding. With the zero psi signal air pressure the governor is not open and not controlling, so the engine is running on a fixed amount a fuel on a locked throttle. After the engine warms up the operator simply raises the pneumatic signal air pressure to the speed adjust mechanism 20 until the engine is running at the desired speed; he loads the engine, then changes a selector valve so that the manual pneumatic signal becomes an automatic signal which varies the speed of the engine in relation to the load, i.e., the pressure upon the inlet pipe 12.
Having described the operation of the engine and the speed adjust mechanism 20 in the operating range from point A to point B on the chart of FIG. 3 further settings of the speed adjust mechanism and the operation of the engine additionally will be described.
At a 3 psi (155 torr) pneumatic signal and a 0.115 inch (3 mm) actuator rod 54 travel position, the lock nuts 104 are set to contact the spherical washer 102. Therefore, any additional deflection of the actuator rod 54 will result not only in the compression of the helical compression spring 72 but also the deflection of the bow springs 92. I.e., there is a lost motion mechanism so that below minimum speeds only one set of springs, the compression low speed springs 72, are resisting the travel of the actuator rod 54. However, in the operating range of the governor, i.e., from the minimum speed to the maximum speed which is from point B to point C on the graph of FIG. 3 that the additional bow normal speed springs 92 also resist and are also biased against further deflections of the actuator rod 54. Basically, the slope of the line from point B to C which is to say the speed response of the engine 16 to different signal air pressures to nipple 70 of the speed adjust mechanism will be determined by the character of the combined springs of the helical compression spring 72 and the bow springs 92. However, inasmuch as the helical compression low speed spring 72 determines the slope of the curve from A to B then the character of the bow normal speed springs 92 are adjusted to determine the slope during the operating range from point B to point C. The character of the springs are primarily determined by using a different bow spring 92 and, therefore, a wide variety of bow springs having different spring constants are used. However, the deflection of the bow springs 92 may be further adjusted by adjusting the range adjusting screws 88. At the point when the maximum engine speed is reached and no higher engine speed is desired, further deflection of actuator rod 54 is limited by bringing the high speed adjustment nut into contact with the top of the bushing retainer 84. It is then locked securely in place by the set screw therein. This will prevent any further actuator rod 54 movement, i.e., any further movement of the speeder plug 38.
Normally, this high speed setting is adjusted at about 15 psi (775 torr) signal air pressure. However, those with ordinary skill in the art will understand that also there is a maximum speed at which the engine is to be operated and the adjustment nut 106 is set so that this maximum engine speed is not exceeded.
An analysis of my system will indicate that the speed adjust mechanism determines whether the governor is to make a low speed response or a normal speed response. I.e., whether the inlet air pressure is under 3 psi or over 3 psi. If the determination is made that the pressure is under 3 psi, only the low speed spring 72 will be in operation which is to say that for any change in fluid pressure at nipple 70 there will produce a large movement of actuator rod 54. By large movement of the actuator rod I mean there will be more movement of the actuator rod for a change in fluid pressure more than in the normal operating range.
On the other hand, if a determination is made that the operation is in the normal speed range which is between points B and C on the graph of FIG. 3, then in that event the equipment will be in the normal speed range. Then in the normal speed range there will be a normal movement of the actuator rod 54 for a change in fluid pressure of the nipple 70 as seen in the graph between the points B and C.
Therefore, it may be seen that not only have I provided a speed adjust mechanism for the governor which is totally enclosed and free of external dust and dirt but also has the desirable feature of the different responses at low air pressure and for normal operating range.
The embodiment shown and described above is only exemplary. I do not claim to have invented all the parts, elements or steps described. Various modifications can be made in the construction, material, arrangement, and operations, and still be within the scope of my invention. The limits of the invention and the bounds of the patent protection are measured by and defined in the following claims. The restrictive description and drawing of the specific example above do not point out what an infringement of this patent would be, but are to enable the reader to make and use the invention.
As an aid to correlating the terms of the claims to the exemplary drawing, the following catalog of elements is provided:
______________________________________10 compressor 60 adjusting screw12 inlet pipe 62 lock nut14 outlet pipe 64 diaphragm16 engine 66 diaphragm case18 governor 68 chamber20 speed adjust mechanism 70 nipple22 sensor/transmittor 72 helical compression springs24 ballhead 74 knobs26 gear 76 spring seat28 drive shaft 78 spring adjuster30 flyweights 80 stud32 toe 82 bushing34 thrust bearing 84 bushing retainer36 speeder rod 86 crosshead38 speeder plug 88 range adjusting screws40 speeder spring 90 lever elements42 rod, shutdown 92 bow springs44 nut, shutdown 94 nuts46 nut, lock 96 alignment pins48 housing/spring case 98 contact pins50 housing, governor 100 loading washer52 adapter 102 spherical washer54 actuator rod 104 lock nuts56 diaphragm plate 106 high speed adjustment nut58 speeder coupler______________________________________
SUBJECT MATTER CLAIMED FOR PROTECTION
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A governor is adjusted as to speed by having a fluid diaphragm directly connected to a speeder spring which acts against a thrust bearing which bears against the flyweight toes. The fluid diaphragm is resisted by a set of low speed springs at all times. A lost motion arrangement brings a set of normal speed springs into use at larger diaphragm movement so that the response to the speed adjustment varies for different values of pressure acting upon the diaphragm.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
[0003] Not Applicable
BACKGROUND OF THE INVENTION
[0004] Periodic flooding of bodies of water has caused serious destruction and loss of life and property. In areas where flooding recurs, dams and levees have been built to contain rising waters. Sometimes theses are sufficient, but more often they are not and the water rises above the levees or is too powerful to be contained and breaks through them.
[0005] There have been many patents for portable dams developed for use in and alongside riverbeds and other waterways, but little has been done to devise portable means to stem the rise of floodwaters other than the use of sandbags. Some inventors have utilized water, sand, gravel, or earth as ballast that are essentially large bags filled with some kind of ballast material. Those include:
[0006] Serota, in U.S. Pat. No. 3,213,628 teaches the use of plastic containers in the shape of a rectangular solid which can be filled with water and lashed together to form a wall or barrier. The device of Serota is best used in a gorge or similar passageway.
[0007] Jackson, III, (U.S. Pat. No. 4,692,060) teaches an elongated water filled tube with side panels in the shape of an equilateral triangle. The tubes are surrounded by wooden frames fastened through loops in the sides of the tubes. The frames are used for support and to help in maintaining the triangular shape of the tubes when filled. A similar device was developed by Coffey (U.S. Pat. No. 4,921,373), but he emphasizes an A-frame structure which can be made from highway or construction. barriers. A flexible tube with triangular cross-section is supported by the frame and filled with water. The units can be placed end to end to extend the wall as needed. Velcro strips on the ends of the tubes facilitate fastening the units together.
[0008] Another long tubular container (can be 100 feet long) with triangular cross-section was developed by Hendrix (U.S. Pat. No. 5,040,919). The device of Hendrix is not in the form of an equilateral triangle, but one having sides of three different lengths. A skirt is attached to the container along the lower front edge to form a seal with the ground to prevent the rising waters from flowing under the unit. This device uses no outside support, but is very heavy when filled with water. Additional units can be placed end to end to provide a long wall. These units cannot be stacked.
[0009] Another approach to the portable module as a flood barrier was taken by Taylor in U.S. Pat. No. 4,981,392. Taylor's module consists of two cylindrical chambers to be filled with water. The modules can be made in varying lengths. They can be placed side-by-side and/or stacked. A staggered stacking pattern can produce a barrier of considerable height and thickness. End to end placement results in a wall of any desired length. There is no mention of a ground seal or any means to prevent the floodwater from passing beneath the modules.
[0010] Another method to the portable module as a flood barrier was taken by Hughes in U.S. Pat. No. 5,470,177. Hughes' module consists of compartmented ballast cells that are to be filled with water, sand, gravel, earth, or other such material. The modules are held in place with lightweight support struts and have a waterproof cover that can be armored to prevent penetration by debris.
[0011] Clark in U.S. Pat. No. 4,375,929 devised another method of flood protection. Clark's module is comprised of metal panels sealingly attachable to one another to form a continuous barrier around a building structure, and sealed with gaskets and attached to a concrete fixed foundation surrounding the structure, and is also abut against the building in order to spread the force of the flood water against the dam structure.
[0012] All of the aforementioned devices may be effective in varying degrees in the path of rising water if the water is not too high, is not coming in rapidly and is not moving with great force. There is still a need for a strong, flexible, portable, continuous barrier of lightweight, water resistant materials that enables its users to erect it quickly and easily using infrastructure that is already in place in both urban and rural areas, giving the user control over water containment and water movement without the hardship and cost of moving and placing vast amounts of sand, water, earth, gravel or other heavy materials that require prodigious amounts of manpower and machinery to place in the short amount of time that containment and control is needed.
DESCRIPTION
[0013] The invention relates to the use of roadway-levees that mitigate flooding, storm surges, and other times when excess water is present in urban or rural areas.
[0014] Damage from floods results from a combination of the great power of flowing water and the concentration of people and property in floodplains, along rivers, and coasts. In the United States over 3,800 towns and cities of more than 2,500 inhabitants are on floodplains. Damaging floods result when the volume of river flow exceeds levels of flood preparedness, either because flow is greater or longer than expected or because of incomplete understanding of local hazards. Roadway-levees are designed to mitigate flood damage.
[0015] The current technology for protecting cities and towns from flooding consists of massive levees and dams. That technology relies on the force of gravity on large, heavy structures made of concrete, and/or earth, and/or sand, and/or gravel. The masses of those structures prevent water from flooding the areas being protected. The roadway-levee uses the same technique in a different form by using the mass of roadways and other cemented or paved surfaces as the underlying foundation or base for holding down and sealing water-resistant barriers.
[0016] Levees are built around or adjacent to populated areas like New Orleans in order to protect them. The current designs are one-wall designs. One-wall designs are like the Titanic, which had one steel layer to hold out seawater. The flaw of one-wall designs is that when a one-wall levee is breached, the entire area behind the levee is flooded, just like the Titanic was flooded and sank. The best solution is to have back-up levees such as the roadway-levee to back-up the large massive levees. In many cases where the floodwater is shallow, only roadway levees may be needed, instead of massive one wall concrete levees and dams.
[0017] The primary locations for the roadway-levee invention are on the roadways, streets, driveways, sidewalks, and other surfaces that enable roadway levees to be sealed against water leakage. The installation of roadway-levees on dirt roadways can be made practicable with the use of the installation of lateral concrete and steel foundations surrounding the area to be protected from flooding.
[0018] Roadways can act as a base of the roadway-levee system and offer the ability to compartmentalize flooding thereby greatly mitigating flood damage. Roadway-levees reduce the spread of floodwaters because of their location and the manner and materials of which they are constructed. Each “city block” or other structures such as government buildings, office buildings, industrial plants or buildings, residential buildings, shopping centers, stadiums, retail buildings, hospitals, etc. is to be surrounded by a roadway-levee to prevent floodwater from entering the protected area. In conjunction with other roadway-levee-protected areas, floodwater damage will be mitigated.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0019] The preferred embodiment shown in FIG. 1 shows a perspective view of a deployed Roadway-levee protecting an enclosed area within and/or surrounding a city/town from flooding. The preferred embodiment shown in FIG. 1 shows a perspective of a deployed Roadway-levee with its water-resistant barrier that is sealed to the street surface, and held vertically by the trusses inhibiting water leakage on either side of the roadway-levee from leaking to the other side of the water-resistant barrier.
[0020] The preferred embodiment shown in FIG. 2 shows a vertical-look down aerial view of a deployed Roadway-levee that is protecting a large enclosed area within and/or surrounding a city/town from flooding. The roadway-levees are deployed in such a way so that water movement from any roadway-levee protected area to another is greatly reduced. Roadway-levees with pumps installed enable any water within the roadway-levee system to be pumped out, thereby mitigating flood damage.
[0021] The Roadway-levee design uses compartmentalization with multiple temporary levees to prevent water from inundating populated areas. Roadway-levees can act as backup devices to large concrete or earth base levees.
[0022] The location of the roadway-levee can be on any surface that can be sealed. By sealed, it is meant that the roadway-levee seal leaks very little. Some leakage can be expected. The surfaces can include but are not limited to streets, sidewalks, alleys, driveways, or even a roadway-levee foundation surrounding a house(s), hospital(s), government buildings, office buildings, industrial plants and/or buildings, and/or other valuable structures.
[0023] A roadway-levee foundation can be anything that allows the seal to work properly that is to prevent or reduce water leakage from one side of the device to the other.
[0024] The Roadway-levee core component is the water-resistant barrier. FIG. 3A shows a plain water barrier without internal or external supports. The top of the water-resistant barrier has holes for attaching carabineers that attach the water-resistant barrier to the rod onto which the water-resistant barrier is hung. The water-resistant barrier is made of material that can resist the weight of standing and flowing water against it. It is resistant to tearing or stretching; and is resistant to water leaking through it.
[0025] The top of the water-resistant barrier has holes for attaching carabineers that attach the water-resistant-barrier to the rod onto which the water-resistant barrier is hung. The bottom portion of the water-resistant barrier ties on top of or is inserted into the bottom or side seal. Carabineers are used in the preferred embodiment due to their ability to hold weight. Other types of hangers may be used in their place.
[0026] FIG. 3B shows a water barrier with vertical ribs inserted into it or attached to the surface of the water-resistant barrier. The top of the water-resistant barrier has holes for attaching carabineers that attach the water-resistant barrier to the rod onto which the water-resistant barrier is hung. The bottom portion of the water-resistant barrier lies on top of or is inserted into the bottom or side seal.
[0027] FIG. 3C shows the water-resistant barrier on top of a seal. It can be attached to the seal mechanically, or with water resistant glue or both. The purpose of the connection of the water-resistant barrier to the bottom and side seals is to create a water-resistant barrier from the roadway surface to several feet up in the air and many hundreds of feet long, thereby protecting an area from flooding.
[0028] FIG. 3D shows the water-resistant barrier inserted into a slot cut part way into the bottom or side seal. It can be attached to the seal mechanically, or with water-resistant glue or both. The purpose of this method is to create a connection of the water-resistant barrier to the bottom and side seals in such a way as to create a “one-piece” construction of the seal with the water-resistant barrier enhancing its ability to create a water-resistant barrier from the roadway surface to several feet up in the air and many hundreds of feet long, thereby protecting an area from flooding.
[0029] FIG. 3E is a carabineer that is used to attach the water-resistant barrier to the rod, which holds the water-resistant barrier in a vertical position giving it support in that position. In the preferred embodiment such devices are used because they are readily available and are engineered to withstand great force, and they can be installed and taken down quickly and easily due to their clip-on design. However, other types of clips may be used as well.
[0030] In the preferred embodiment, straight rods and/or curved rods may be used to hold up the water-resistant barrier between the trusses or scaffoldings. FIG. 4A and FIG. 4B show two types of rods. The rods go through holes in the adjustable truss top. The truss top holds up the rod, which holds the water-resistant barrier vertically. FIG. 4A shows a straight rod and 4 B shows a corner rod, which makes a 90-degree turn.
[0031] In the preferred embodiment, FIGS. 5A and 5B show a bottom or side seal. The purpose of the bottom seal is to prevent water from leaking underneath or around the roadway-levee. The seal is made of a rubber-like pad that, when compressed by trusses and laterals or glued to the roadway surface, conforms to the paved surface and thereby prevents water from leaking under the roadway-levee thereby creating a water-resistant seal. It is made of materials that allow it to be compressed mechanically or to be glued onto the roadway surface. It is thick enough to allow it to conform to the underlying street surface with all of its imperfections thereby creating a seal. The seal may or may not have water-resistant glue that adheres to the bottom of he seal to the paved surface. It may do this sideways or lengthways. In any case it will resist water leakage as long as the roadway is constructed to normal construction standards. It may be made out of natural materials, fibers, metal supports, such as rubber or man-made such as plastic or other man-made materials or combinations thereof. FIG. 5A shows a plain bottom or side with no slot or holes.
[0032] FIG. 5B shows a bottom or side seal with a slot. The purpose of the slot is to allow a water-resistant barrier to be inserted into it. The purpose of this method is to create a connection of the water-resistant barrier to the bottom and side seals in such a way as to create a “one-piece” construction of the seal with the water-resistant barrier enhancing its ability to create a water-resistant barrier from the roadway surface to several feet up in the air and many hundreds of feet long, thereby protecting an area from flooding.
[0033] FIG. 6 shows a cut-away view of a side seal or bottom seal, where a seal is used to connect two water-resistant barriers on either side of it has a slot cut into it, allowing the insertion of seal on both sides, thereby allowing two water-resistant barriers to be connected, thereby expanding the length of the barrier. The water-resistant barrier connected in this way may be glued or mechanically sealed to the seal so that no water leaks, in around or under the assemblage.
[0034] The Roadway-levee structure shown in FIG. 7 shows a more detailed side view of a water-resistant barrier that is held upright by trusses or scaffolding. The Roadway-levee and laterals are held down to the pavement by anchor bolts set Into the foundations and/or with water-resistant glue, which have been placed into or onto paved surface(s) before or during flooding. The combination of the trusses and laterals hold down and compress the bottom of the water-resistant barrier onto or in the seal thereby sealing the water-resistant barrier to the roadway's or foundation's surface.
[0035] The water-resistant barrier may be glued onto or into the seal making the seal and water-resistant barrier one construct thereby reducing the possibility of leaks. A preferred embodiment shown in FIG. 7 shows a side view of a deployed Roadway-levee with its water-resistant barrier that is sealed to the street surface with water-resistant glue, and held vertically by the trusses inhibiting water leakage on either side of the roadway-levee from leaking to the other side of the water-resistant barrier.
[0036] A preferred embodiment shown in FIG. 8 shows a side view of a deployed roadway-levee truss or scaffolding with its water-resistant barrier that is sealed to roadway surfaces with hold-down devices consisting of concrete and steel foundations, anchor-bolts, with or without water-resistant glue. Trusses or scaffoldings hold the water-resistant barrier up vertically, thereby inhibiting water leakage on either side of the roadway-levee from leaking to the other side of the roadway-levee.
[0037] FIG. 9A shows an adjustable truss top. The top hole is for the insertion of the rod that holds up the water-resistant barrier. The smaller holes are for the insertion of the spring pin. The spring is to push up on the adjustable truss top into which the rod is inserted. This pushes up on the rod and holds the water-resistant barrier vertically exerting constant pressure on it vertically.
[0038] FIG. 9B shows a truss top spring pin. The purpose of the pin is to serve as the pressure point for the spring. It may be inserted into the truss top at different points to allow for variations in topography of the roadway, and different heights of water-resistant barriers.
[0039] FIG. 9C shows a spring pinhole on the truss top and is also a cross section of the spring-pin that is to be inserted into it. The slots allow for the insertion of the pin through the truss top when it can be turned thereby locking into place so it won't fall out.
[0040] FIG. 10 shows a spring. The purpose of the spring is to push up on the top truss from the truss base thereby creating upward pressure on the water-resistant barrier, holding it vertically and resisting the lateral pressure of water pressing against it on one side or two sides.
[0041] FIG. 11 shows the truss bottom, the truss top inserted into the truss bottom. Pin welded onto the truss bottom acts as a base for the spring. The spring goes up to the truss top pin.
[0042] FIG. 12 shows a water-resistant barrier inserted into a seal. It also shows a nut and bolt holding a truss base lateral. In this case the seal is glued to the roadway surface. The glue is water-resistant glue that allows the system to be installed before, during, or after flooding. The strength of the glue enables the roadway levee to be attached to the roadway surface creating a water-resistant seal.
[0043] FIG. 13 shows the adjustable lateral support, which attaches the truss at the mid-level of the truss or at the top of the truss to adjacent trusses. The purpose of the lateral support is to support the trusses in a vertical position when water is on either or both sides of the roadway-levee. Water is heavy and the force of stationary or moving water will place substantial lateral force on the truss making a lateral support needed but not necessarily required, The hold-down bolts will transfer much of the lateral force of the water to the foundation of the roadway-levee.
[0044] FIG. 14 is a perspective view of a lateral support truss foot with a rubber-like sole. The adjustable lateral truss will be made of metal, plastic, or other hard material. The rubber-like 3 sole may be used to us not required. The purpose of the rubber-like sole may be used but is not required. The purpose of the rubber-like sole is to allow for compression so that the lateral support can be adjusted to the height of the street. It may or may not be glued to the roadway surface or the foundation surface when it is installed.
[0045] FIG. 15A is a vertical lookdown view of the bottom side-truss. This side truss is made out of metal, plastic, or some other hard material. The purpose of the side truss is to compress the seal onto the surface of the roadway, thereby creating a water-resistant seal.
[0046] FIG. 15B is a perspective view of the bottom-side truss. The holes at each end of the bottom-side truss are for the anchor bolts which hold down the truss and the bottom-side trusses to the foundation. Alternatively, the holes can be used to attach the bottom-side truss to the trusses. This may be used when there is no anchor bolt (mechanical fastener) holding down the roadway-levee, which is held down with glue instead.
[0047] FIG. 16A is a perspective view of the bottom side truss overlaying the water-resistant barrier.
[0048] FIG. 16B is a side view of a bottom side truss overlaying a water-resistant barrier where an anchor bolt is inserted. The anchor bolt connects the foundation to the water-resistant barrier and trusses and holds them down and helps create a water-resistant seal.
[0049] FIG. 17A is a perspective view of the mid-side trusses the purpose of which is to provide support to the water-resistant barrier to help resist bowing of the water-resistant barrier when pressure is pressing against it. The holes on the ends of the mid-side trusses are to enable the mid-side trusses to be fastened to the trusses with a truss pin. Is an end view of the mid-level lateral truss. One embodiment is to attach the mid-side trusses to the trusses using a knob or a pin that is attached to the trusses, which the mid-side trusses can fit into.
[0050] FIG. 17B is an end view of the mid-level lateral truss. One embodiment is to attach the mid-side trusses to the trusses using a knob that is welded onto the trusses, which the mid-side trusses can fit onto. The holes on the ends of the mid-side trusses are to enable the mid-side trusses to be fastened to the trusses with a truss pin.
[0051] FIG. 17C is a side view of the truss pin that attaches the mid-level truss to the truss.
[0052] FIG. 18 shows perspectives of a corner truss. Corner trusses are to be installed at the corners to support the water-resistant barrier where it is turned. Corner trusses are to also seal the corners to the roadway or paved surface.
[0053] As shown in FIG. 18A , a corner truss is needed to prevent water from leaking there and to enable the water-resistant barrier to be installed at a 90-degree turn. A corner truss seals the water-resistant barrier in a similar fashion as the bottom seal, using rubber-like seal in a vertical fashion, thereby making the corner water-resistant. Water-resistant glue may be used. The corner truss is held down to the roadway using the same type of foundation, e.g. concrete and steel and anchor bolts, and/or water-resistant glue as the linear portion of the Roadway-levee.
[0054] As shown in FIG. 18B , the corner trusses may have pumps atop them. The pumps direct floodwater out of the area surrounded by the roadway-levee. The pump may also be connected to a water level detector that is connected to a telecommunications device for monitoring water levels offsite. As shown in FIG. 18B , a telecommunications device can be used by a centrally located computer the purpose of which is to control the water level within each roadway-levee-enclosed area.
[0055] As shown in FIG. 18C , the corner trusses is a vertical view of a corner truss. Corner trusses may or may not have valves that open and close directing water in the chosen direction so that the water can be drained out of the roadway-levee.
[0056] FIG. 19 shows a vertical view of an alternative corner truss with a solid core design thereby supporting the water-resistant barrier from higher-pressure situations.
[0057] As shown in FIGS. 20A and 20B , when a mechanical foundation is used, rather than a glued seal foundation, the foundation consists of concrete and steel foundation that is installed beneath the surface of the roadway prior to flooding.
[0058] FIG. 20A is a side cut-away view of a foundation. The depth, diameter and other dimensions will vary depending on the conditions on-site.
[0059] FIG. 20B is a perspective view of the same type of foundation. The notch at the top allows for he installation of a cover, that when installed lies flush with the street. When the concrete is poured anchor bolts are set into the wet, unhardened concrete at a level under the paved surface. The concrete hardens and creates a heavy mass that serves to immobilize the roadway levee when it is attached thereto.
[0060] FIG. 21A shows an anchor bolt with an oblong-eye and FIG. 21B shows an anchor bolt with a round-eye. The purpose of this type of fastener is to allow the use of bolt-hooks that are attached to the trusses and truss laterals when flooding has occurred or is occurring when the roadway-levee is installed. That is to say, when conditions are difficult like they were when Katrina flooded New Orleans. In those conditions, where there are several feet of standing water, regular nuts may not be practicable. The round tops allow hooks to be used so that the trusses may be installed in several feet of water and allow the area within the roadway levee to be drained using pumps.
[0061] As shown in FIG. 22A , when not in use, the anchor bolts and foundation are covered with a steel cover that is strong enough to allow vehicular traffic to run over it without harming the anchor bolts or the foundation.
[0062] As shown in FIG. 22B , is a side cut-away view of the metal ring. FIG. 22C is a perspective view of the ring. The ring is installed above the foundation, and is the base for the steel cover described in FIG. 22A . The metal top, and a reflector, which covers the foundation, so that when it is not being used for the roadway-levee it, is a roadway reflector. This device serves as a location device and it serves as a street reflector.
[0063] FIG. 23A shows a side cut-away view and FIG. 23B shows a perspective cut-away view of a reflector.
[0064] As shown in FIG. 1 , laterals are held down to the pavement with anchor bolts, and may share the bolts with the trusses.
[0065] Although the description above contains many specifications, these should not be constructed as limiting the scope of the invention but merely providing illustrations of some of the presently preferred embodiments of this invention. For example, the trusses can have other shapes, such as triangular, circular, oval, square, trapezoidal, etc.; the seal can have other shapes, and materials, with or without glue, etc.; there may or may not be computer system(s), or pump(s), or water level detector(s). Thus the scope of the invention should be determined by the claims and their legal equivalents, rather than by the examples given.
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A water or flood control and containment system is provided having foundations, sealed bases, supporting structure, and pumping system that gives the user control over water containment and movement either to reduce the water hazard or to store water. The bases are secured and sealed to paved surfaces with foundations that have been preset into the street or other prepared foundation. When deployed on multiple adjacent streets, roadway levee creates a compartmented barrier containment system that mitigates flooding and storm surges. The invention is to be removed and stored off site when not in use.
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CROSS REFERENCE TO RELATED APPLICATIONS
This is continuation-in-part of the following U.S. patent applications, the disclosures of which are incorporated by reference: application Ser. No. 07/839,510, filed Feb. 21, 1992 for Needle Manipulator; application Ser. No. 07/850,674, filed Mar. 13, 1992 for Endoscopic Surgical Instrument; application Ser. No. 07/878,957, filed May 4, 1992 for Axially Extendable Endoscopic Surgical Instrument.
BACKGROUND OF THE INVENTION
The practice of endoscopic or minimally-invasive surgery is becoming more widely used because it is less traumatic than conventional open surgery, thus reducing hospitalization times and costs as well as minimizing patient discomfort. With endoscopic surgery, only a relatively tiny incision is necessary, with the instrument being passed through this incision. A tissue-protective port is sometimes used to minimize tissue trauma on the walls of the incision. Various types of endoscopic instruments are passed through the small incision and appropriate surgical procedures are carried out.
One type of endoscopic instrument is forceps having tips specially configured to grasp, manipulate or cut tissue. Conventional forceps typically use scissors type of thumb and finger rings. Such forceps, although well designed for cutting and simple grasping tasks for open surgical procedures, are unwieldy for certain minimally-invasive surgical tasks, such as placing sutures during endoscopic procedures; conventional forceps require the physician to reposition the entire instrument to adjust the radial orientation of the tip.
SUMMARY OF THE INVENTION
The present invention is directed to a minimally-invasive surgical instrument which permits the physician to axially increase or decrease the length of the instrument at any time, while retaining full function and precise control of the tip assembly. The physician can also independently actuate the tip and rotate the tip through non-rotational, planar manipulation of the handle control assembly. This is accomplished without requiring the physician to rotate his or her wrist.
The extension/retraction capability of the instrument is achieved by a combination of two extension mechanisms, each containing a rod and a tube to receive the rod, the tube and rod mated by threads so that axial extension is achieved by rotating the tube relative to the rod or the rod relative to the tube. In preferred embodiments of the invention, the two mechanisms are positioned one inside the other, so that the rod of the outer mechanism is hollow and receives the tube and rod of the inner mechanism. The two mechanisms are functionally linked together so that extension of one produces extension of the other.
Other features and advantages of the invention will be evident from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an overall perspective view of a needle manipulator type of endoscopic surgical instrument;
FIG. 2 is an exploded isometric view of the needle manipulator of FIG. 1;
FIG. 3 is a cross-sectional view of a portion of the needle manipulator of FIG. 1 with the jaws in a closed position;
FIGS. 3A-3D show portions of the needle manipulator of FIG. 3 enlarged to show detail;
FIG. 4 shows the needle manipulator of FIG. 3 with the jaws in the open position;
FIG. 5 is a cross-sectional view of a portion of the needle manipulator of FIG. 1 taken in a plane perpendicular to the plane of FIG. 3;
FIG. 6 is an enlarged view of the tip assembly of FIG. 1 shown manipulating a needle to suture tissue;
FIGS. 6A and 6B illustrate the rotary movement of the tip assembly and needle of FIG. 6 as the trigger is pulled and pushed, respectively;
FIGS. 7 and 7A are enlarged plan and side views of the needle of FIG. 6 showing the attachment of the suture material and the special shape of the needle;
FIG. 7B illustrates the progression of the needle of FIG. 6 after successive stitches caused by rotation of the tip assembly and needle;
FIGS. 8A, 8B and 8C are side views of a grasping type of endoscopic medical instrument made according to the invention shown in a closed jaw position in FIG. 8A, an open-jaw position in FIG. 8B with the tip assembly rotated 90° from the position of FIG. 8A, and a closed jaw position in FIG. 8C with the tip assembly rotated 180° from the position of FIG. 8A;
FIGS. 9A and 9B are exploded isometric views of the distal and proximal portions of the instrument of FIG. 8 shown with straight rather than doglegged jaws;
FIGS. 10A and 10B are longitudinal cross-sectional views of the distal and proximal portions of the instrument of FIGS. 9A and 9B;
FIG. 11 is an exploded view of an embodiment of the invention which shows the axial extension capability of the instrument;
FIG. 12 is an exploded isometric view, similar to FIG. 9A, of the distal portion of an alternative embodiment of the instrument of FIG. 8 in which the user can selectively lock out relative rotary motion between the tube assembly and the body, and also showing a user removable tip assembly;
FIG. 13 is an enlarged cross-sectional assembled view of the distal end of the portion of the instrument shown in FIG. 12 with the jaws partially open;
FIGS. 13A and 13B are external views of an alternative embodiment of the instrument of FIG. 8 incorporating the distal portion of FIG. 12 shown in partially open and closed positions;
FIG. 14 is an enlarged assembled view of the proximal end of the instrument portion shown in FIG. 12 shown mounted to the base; and
FIGS. 15A and 15B are enlarged cross-sectional views taken along line 15--15 of FIG. 14 showing the serrated lockout collar in its free movement position in FIG. 15A, which allows the tip assembly to rotate freely relative to the body, and the rotary motion lockout position of FIG. 15B, showing the frictional engagement of the lockout fingers, formed as part of the base extension, with the tip carrier tube thereby preventing the tip carrier tube, and the tip assembly therewith, from rotating relative to the base.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a rotational tip needle manipulator type of endoscopic surgical instrument. Needle manipulator 2 includes an elongate body 4, the body including a base 6 and an elongate tip carrier tube 8. Manipulator 2 also includes a tip assembly 10 mounted to the distal end 12 of tube 8 and a jaw driver assembly 14. Jaw driver assembly 14 is used to manipulate the jaws carried by the tip assembly as is described below through the opening and closing of jaw actuating finger and thumb loops 16, 18. Manipulator 2 further includes a jaw rotator assembly 20 used to rotate tip carrier tube 8 and tip assembly 10 therewith about the longitudinal axis 22 of the manipulator.
FIG. 2 illustrates tip assembly 10 as including a tip 24 having a fixed jaw 26 integral with tip 24 and a movable jaw 28 secured to tip 24 by a pivot pin 30. Tip assembly 10 also includes an adapter 32 sized to fit within and slide within the hollow interior of tip assembly 10. Adapter is held within the interior of tip 24 by a ring 33 press fit into the tip interior. Adapter 32 has a cam slot 34 within which a drive pin 36 extending from an end 38 of movable jaw 28 rides. Thus, axial movement, that is movement parallel to axis 22, of adapter 32 causes movable jaw 28 to move from the closed jaw position of FIG. 3 to the open jaw position of FIG. 4. This is accomplished by the manipulation of jaw driver assembly 14. (See FIG. 1.)
Jaw driver assembly 14 includes finger and thumb loops 16, 18 coupled to an axial drive rod 40 through the engagement of idler gears 42 with drive gear segments 44 formed on finger and thumb loops 16, 18 and a rotary rack 46 formed on the proximal end of 48 of drive rod 40. Rack 46 is secured to end 48 by a screw 49 to permit rack 46 to rotate freely. Adapter 32 includes a threaded tip 50 which engages a threaded hole 52 at the distal end of 54 of rod 40. Finger and thumb loops 16, 18 are pivotally mounted to base 6 through the use of pivot pins 56 passing through pivot holes 58 formed in loops 16, 18 and pivot pin bores 60 formed in base 6. Idler gears 42 are secured to base 6 by idler gear pins 62 which pass through bores in the idler gears and through idler gear pin holes 64 in base 6.
Tip carrier tube 8 has an annular shoulder 66 sized and positioned to seat against a thrust bearing 67 supported by an internal annular surface 68 formed at the distal end 70 of barrel portion 72 of base 6. See FIG. 3D. The proximal end 74 of tube 8 is maintained within base 6 by an externally threaded ring 76. Ring 76 is sized so that when the ring is secured against distal end 70 of barrel portion 72, tube 8 is securely mounted to base 6 but is free to rotate within the base. Thrust bearing 67 helps to ensure the free rotation of tube 8 during use.
Jaw rotator assembly 20 includes a rotary actuator trigger 78 having a finger loop 80 at its proximal end and a cam pin 82 at its distal end. Trigger 78 incudes elongate portion 84 having a dovetail or trapezoidal cross-sectional shape which slides within a similarly configured dovetail slot 86 formed along the length of base 6. Pin 82 passes through an axial slot 88 formed in barrel portion 72 along slot 86. Pin 82 passes through slot 88 to engage a spiral groove 90 formed in proximal end 74 of tube 8. Pin 82 includes a ring 83 which rides within slot 88 and a guide 85 which rides within spiral groove 90, both ring 83 and guide 85 preferably made of PTFE. Thus, axial movement of trigger 78 causes pin 82 to ride along spiral groove 90, thus rotating tube 8 and tip assembly 10 therewith about axis 22.
Tip assembly 10 is secured to tip carrier tube 8 using a hollow tip mounting tube 92. Tip mounting tube 92 has external threads 94 at its distal end 96 which engage internal threads 98 formed within the interior of tip 24. Tip 24 and tip carrier tube 8 have opposed, complementary tooth surfaces 100, 102 which, when engaged, keep tip assembly 10 from rotating relative to tip carrier tube 8. Tube 8, mounting tube 92 and drive rod 40 are secured to one another by a common pin 104. Pin 104 passes through a bore 106 in mounting tube 92, a short slot 108 in carrier tube 8 and a long slot 110 in drive rod 40. Common pin 104 is maintained at the proximal end 112 of slot 108, thus keeping tooth surfaces 102, 100 engaged, through the use of an internally threaded ring 114 threaded onto external threads 116 formed on the outside of tube 8 adjacent slot 108. Slot 110, being longer than slot 108, can still move axially through the manipulation of finger and thumb loops 16, 18, thus causing jaws 26, 28 to open and close.
A suture material supply spool 89 is mounted to finger loop 80 through the use of snap flanges 91 which engage the inside of the finger loop. Suture material 93 is directed from needle 118, through hole 99 in tube 8, through slots 95, 97 in rod 40 and tube 92, through the center of rod 40 and is wound about spool 89.
The operation of needle manipulator 2 will now be described. The user places his or her thumb and middle finger through thumb and finger loops 18, 16. Loops 18, 16 are separated, as suggested in FIG. 4, causing drive gear segments 44 to rotate idler gears 42 which, in turn, drive rotary rack 46 axially, that is parallel to axis 22. This causes adapter 32 to move axially so that drive pin 36 moves along cam slot 34, thus opening jaws 26, 28 through the pivotal movement of movable jaw 28. A needle 118 is placed between jaws 26, 28 and is secured in place by moving finger loops 16, 18 back towards one another to the position of FIGS. 1 and 3. Needle 118 is locked between jaws 26, 28 through the engagement of catches 120, 122 carried by loops 16, 18. The manipulation of rotary actuator trigger 78 parallel to axis 22 causes pin 82 to ride along spiral groove 90, thus rotating tip carrier tube 8 and tip assembly 10 therewith about axis 22. Tip mounting tube 92 and axial drive rod 40 are likewise rotated about axis 22 upon the actuation of trigger 78 due to the interlocking engagement of common pin 104 with all three members. With needle manipulator 2, the user's hand, wrist and arm can be generally aligned with axis 22 for enhanced control.
The reciprocal movement of trigger 78 causes tip assembly 10 and needle 93 to move in opposite rotary directions. See FIGS. 6, 6A and 6B. In the preferred embodiment this movement is through an arc of about 240°. Only when needle 93 is moved in the appropriate rotary direction, clockwise in FIG. 6, will the needle pierce tissue 128. After the piercing movement, the user releases needle 118 from between jaws 26, 28, rotates tip assembly 10 in the opposite direction, regrasps needle 118 between jaws 26, 28, pulls needle 118 completely through tissue 128, repositions needle 118 between jaws 26, 28 at a position 126 along the needle and repeats the process.
Needle 118 has a generally elliptical shape with a main portion 124 having a generally circular shape. Needle 118 can be grasped between jaws 26, 28 at a position 126 adjacent the attachment point for suture material. Point 126 is located at about the center of the generally circular arc formed by a main portion 124 so that when tip assembly 10 is rotated about axis 22, main portion 124 moves along a generally circular path. This minimizes trauma to tissue 128 and makes the procedure easier to perform.
Turning now to FIGS. 8-10B, an alternative embodiment of the endoscopic medical instrument of FIGS. 1-7B is shown. Parts of the alternative embodiment which correspond to the embodiment of FIG. 1 have like reference numerals. The alternative embodiment is an endoscopic medical instrument of the grasping type having a pair of movable jaws 28a, 28b as part of the tip assembly 10a Instrument 2a includes broadly an elongate body 4a, a tip assembly 10a removably mounted to the distal end 12a of a tip carrier tube 8a, a driver assembly 14a, which causes jaws 28a, 28b to move between their open and closed positions, and a jaw rotator assembly 20a, which causes tip assembly 10a, and jaws 28a, 28b therewith, to rotate about axis 22a.
Jaws 28a, 28b include outer portions 140 and arm portions 142 connected by hubs 144 having holes 146 formed therein. Tip assembly 10a also includes a circular, hollow tip coupler plug 148 having a through hole 150 formed perpendicular to axis 22a. Jaws 28a, 28b are mounted within tip coupler plug 148 and are pivotally secured within the plug by pivot pin 30a. The interior of tip coupler plug 148 is sized to permit jaws 28a, 28b to move between their open and closed positions of FIGS. 8A and 8B.
Tip coupler plug 148 has external threads 152 formed on one end. Threads 152 are sized to engage internal threads 154 formed at distal end 12a of tip carrier tube 8a. In this way, tip assembly 10a can be removably secured to body 4a of instrument 2a. Tip carrier tube 8a is sized so that proximal end 74a fits within the hollow interior 156 of base 6a. Base 6a, as shown in FIG. 10B, has an inner shoulder 158 which supports annular shoulder 66a of tip carrier tube 8a. A set of ball bearings 160 is positioned between shoulder 66a and shoulder 158. Another set of ball bearings 162 is situated between annular shoulder 66a and an inner shoulder 164 of a tip carrier tube retaining nut 166. Nut 166 has a threaded interior 168 which engages the threaded exterior 170 of base 6a. Shoulders 158, 164 are positioned so that tip carrier tube 8a is secured axially to base 6a but is allowed relatively free rotary movement with respect to the base by virtue of ball bearing sets 160, 162.
Finger and thumb loops 16a, 18a are pivotally mounted to lugs 172 of base 6a using pins 174 which pass through openings 176 formed in the clevis ends 178 of loops 16a, 18a and corresponding holes 180 formed in lugs 172. Manipulation of loops 16a, 18a is used to open and close jaws 28a, 28b and will be discussed below.
Base 8a has flat face 182 extending substantially along its entire length. A hollowed out cover 184 is secured to base 6a by a pair of screws 186, 188. Screw 186 threads into a hole 190 in base 6a adjacent the distal end of flat face 182. Screw 188 passes through the hollow interior 192 of a standoff 194 and engages a threaded hole 196 formed in flat face 182 at the proximal end of axial slot 88a. A roller 200 is sized to be mounted over and rotate freely about standoff 194. Roller 200 is sized to fit within a slot 202 formed in trigger 78a and helps to stabilize trigger 78a as the trigger moves parallel to axis 22a. The stability of trigger 78a is also aided by the use of a pair of rollers 204 on either side of trigger 78a at the distal end 206 of the trigger. Rollers 204 ride between surface 182 and the overlying surface 208, as seen in FIG. 10B, of cover 184. Side to side movement of distal end 206 of trigger 78a is restricted by engagement of a roller 210 mounted in a slot 212 at distal end 206 of trigger 78a by a pin 214. Roller 210 is sized to ride along the side surfaces 215 of the hollow interior of cover 184.
Trigger 78a also includes a cam pin 82a. Cam pin 82a includes a cam roller 216 secured to distal end 206 by a pin 218. Cam pin 82a is positioned to extend through axial slot 88a and engage spiral groove 90a at proximal end 74a of tip carrier tube 8a. Thus, axial movement of trigger 78a causes cam pin 82a to move along spiral groove 90a, thus rotating tip carrier tube 8a and tip assembly 10a therewith about axis 22a.
FIG. 10B shows that proximal end 74a is thicker than the remainder of base 8a. This is to provide a deeper spiral groove 90a and thus a better camming surface for cam roller 216 to ride against. This dual wall thickness is achieved by overlapping tubes having different wall thicknesses as shown at overlapping region 219.
Lateral support of proximal end 74a within base 6a is aided by the use of a set of ball bearings 220 housed within an annular cavity 222. Cavity 222 is defined between the tip 224 of end 74a and a cupped shaped region 226 formed within base 6a adjacent proximal end 198.
The remainder of jaw driver assembly 14a, in addition to finger and thumb loops 16a, 18a, will now be discussed. As shown in FIG. 9A, an axial drive tube assembly 230 includes an axial drive tube 232 having a plug 234 at a proximal end 236. Plug 234 has a transverse bore 238 through which a common pin 240 passes. Pin 240 also passes through aligned bores 242 formed in the overlapping ends 244, 246 of links 248, 250. Links 248, 250 are pivotally connected to finger and thumb loops 16a, 18a by pins 252 passing through holes 254, 256 formed in links 248, 250 and loops 16a, 18a. Thus, movement of finger and thumb loops 16a, 18a towards and away from each other causes links 248, 250 to articulate, thus driving axial drive tube 232 along axis 22a.
Axial drive tube assembly 230 also includes a flanged draw bar 258 with a flange 260 at a proximal end thereof. Flange 260 is sized to lie adjacent an internal shoulder 262 formed at the distal end 263 of tube 232 with a set of ball bearings 264 captured therebetween. A second set of ball bearings 266 is positioned on the other side of flange 260. A draw bar retaining nut 268 has a central bore 270 sized to fit over flanged draw bar 258. Nut 268 has an internal shoulder 272 which rests against the lip 274 of tube 232 to capture ball bearings 266 between nut 268, bar 258 and tube 232. Flanged draw bar 258 is thus fixed axially to axial drive tube 232 but is allowed to freely rotate within the axial drive tube.
The distal end 276 of bar 258 fits within a cut-out region 278 formed in a flattened rectangular cam block 280. Cam block 280 is secured to distal end 276 by a pin 282 passing through both. Cam block 280 has a pair of slots 284, 286 formed on either side of cam block 280 and angled in opposite directions. Arms 142 of jaws 28a, 28b each have inwardly extending pins 288 sized to engage slots 284, 286. Thus, axial movement of axial drive tube 232, which also moves flanged draw bar 258 and cam block 280 therewith, causes cam block 280 to move parallel to axis 22a thus causing pins 288 to slide along slots 284, 286; this causes jaws 28a, 28b to open and close in a grasping action.
Axial drive tube assembly 230 also includes a fork assembly 290 for stabilizing cam block 280 during use. Fork assembly 290 includes a fork 292 having a pair of arms 294 defining wider and narrower gaps 296, 298 therebetween. Wider gap 296 is sized to encompass arms 142 of movable jaws 28a, 28b while narrower gap 298 is sized to lie along either side and guide cam block 280.
Fork assembly 290 also includes a U-collar 300 having a slot 302 formed therein. Slot 302 is sized to fit loosely within an annular groove 304 formed at the proximal end 306 of fork 292. The outer circumference of U-collar 300 is sized to create a relatively tight friction fit within the interior 308 of tip carrier tube 8a. Thus, fork assembly 290 is fixed axially within tip carrier tube 8a while flanged draw bar 258 moves axially with fork 292.
Fork assembly 290 also includes a spring 310 partially housed within a fork spring slot 312 formed in fork 292 between groove 304 and narrower gap 298. Spring 310 is sized and positioned to engage a tube spring slot 314 formed in tip carrier tube 8a. In this way, fork assembly 290 is kept from rotating axially within tip carrier tube 8a. However, when first mounting tip assembly 10a to distal end 12a of tip carrier tube 8a, the user can depress spring 310 and allow fork assembly 290 to rotate along with cam block 280, tip assembly 10a and flange draw bar 258 until tip coupler plug 148 is screwed fully onto threads 154 of tip carrier tube 8a. At this point, spring 310 is allowed to freely enter slot 314 to prevent fork assembly 292 from rotating within tip carrier tube 8a. Thus, fork assembly 290 is used for two primary purposes: to guide and stabilize cam block 280 and arms 242 of jaws 28a, 28b and to keep tip assembly 10a from unscrewing from tip carrier tube 8a.
In use, assuming tip assembly 10a must be changed, spring 310 is depressed through slot 314 and tip assembly 10a is unscrewed from internal threads 154 at distal end 12a of tip carrier tube 8a. An appropriate tip assembly is then threaded onto distal end 12a. Using tip assembly 10a, pins 288 are guided into slots 284, 286 to permit both jaws 28a, 28b to move. In appropriate cases, a different cam block 280 could be used to accommodate a different type of motion; also, the tip assembly could be constructed so that only one jaw moves. Tip assembly 10a is rotated about axis 22a by the manipulation of trigger 78a. The axial movement of trigger 78a causes tip carrier tube 8a and tip assembly 10a secured thereto to rotate about axis 22a. Once properly oriented, the user opens and shuts jaws 28a, 28b by opening and closing finger and thumb loops 16a, 18a. Doing so articulates links 248, 250 which are coupled to axial drive tube 232 through common pin 240 and plug 234. Axial movement of drive tube 232 causes like axial movement of drawbar 258 which, being pinned to cam block 280 by pin 282, moves the cam block axially along axis 22a. The axial movement of cam block 280 causes transverse pivotal movement of jaws 28a, 28b as pins 288 ride along slots 284, 286 to provide the desired grasping action.
The invention has been shown in two different embodiments, one specially adapted as an endoscopic needle manipulator while the other as an endoscopic tissue grasper or manipulator. The invention can also be practiced using tips and tip assemblies configured for other uses. For example, tip assemblies adapted for dilating a region, cutting tissue, stapling tissue or knotting suture material could be used as well.
Turning now to FIG. 11, an embodiment of the invention is shown which permits the user to extend the length of the instrument and thereby advance the tip assembly without advancing the proximal end of the instrument. A tube 401 with a spiral groove 402 at the proximal end thereof serves the same function as the corresponding spiral groove 90 on he proximal end 74 of the tube 8 in the embodiment of FIG. 2. Fitting over the distal end 403 of the tube 401 in this embodiment however is a barrel 404, which is secured to the tube 401 by an adaptor nut 405. Passing through the barrel 404 is a hollow spindle 406 which exceeds the barrel in length and protrudes from the distal end 407 of the barrel. The spindle 406 contains a broad thread 408 formed on its exterior surface beginning at the proximal end and extending only a short distance along the spindle. This broad thread is mated with a corresponding thread 410 along the inner surface of the barrel 404, extending substantially the full length of the barrel. A typical pitch of the thread is five threads to the inch. The distal end 409 of the spindle 406 which protrudes from the distal end 407 of the barrel 404 may thus be turned by one's fingers, which will cause the thread 408 on the external surface of the spindle to travel along the thread along the internal surface of the barrel, and thereby cause the spindle to move axially within the barrel.
This axial movement of the spindle 406 relative to the barrel 404 is matched by a corresponding axial movement of smaller diameter elements retained inside the spindle and barrel, which in turn communicate the axial movement to the tip assembly. These inner, smaller diameter elements include a hollow draw tube 411 and a draw bar 412 which passes through the draw tube 411. The draw bar 412 has broad threads 413 formed along its outer surface, and these are mated to corresponding broad threads 414 along the inner surface of the draw tube 411. These threads are of the same pitch as the threads 408 on the spindle 406.
A pin 415 affixed to the spindle 406 and extending inward engages a slot 416 on the draw bar, and thus the turning of the spindle causes a simultaneous turning of the draw bar. Since the threads 413 on the draw bar are of the same pitch as the thread 408 on the spindle, the turning of the spindle causes the draw bar to turn at the same rate and advance relative to the draw tube 411 at the same linear rate in the axial direction as the spindle relative to the barrel 407.
At the distal end 417 of the draw bar is an extension rod 418, secured to the draw bar by a threaded nut 419. The components at the distal end of the extension bar are a fork assembly 420, a U-collar 421, a cam block assembly 422, a pin 423, jaw pivot 424, and a pair of jaws 425, 426, which are analogous to those of the embodiment shown in FIG. 9A, and operate in the same manner. A locking spring 43i extends outward from the fork assembly 420 to extend into a slot 432 in the spindle. This joins the fork assembly to the spindle.
Secured to the proximal end of the draw tube 411 are a second draw bar 433, two ball bearing races 434, 435 and a nut 436, which are analogous to and function in the same manner as the corresponding elements in the embodiment of FIG. 9A. Other elements included in the structure and associated with the tube 401 containing the spiral groove are a retaining nut 427 and three sets of ball bearings 428, 429, 430. Each of these elements is analogous to and serves the same function as the corresponding retaining nut 166 and ball bearings 162, 160, 220 of the embodiment of FIG. 9A.
A further connecting element is a pin 441 which passes through a longitudinal slot 442 in the spiral groove tube 401, as well as the proximal end of the draw tube 411 and the distal end of the second draw bar 433, keeping these three elements in rotational alignment.
The extension of the tip assembly elements is therefore achieved by manually twisting the spindle 406 at a location extending distal to the distal end 407 of the barrel 404. As the spindle and barrel combination are being elongated, the internal draw assembly consisting of the draw bar 412 and draw tube 411 are being elongated at the same rate. This maintains the jaws 425, 426 in harmony with the action of the finger handles, which although not shown in this figure are identical to those shown in FIG. 1. Once the desired extension has been achieved, the spindle 406 may be locked into position relative to the barrel 404 by a clamp nut 437, which compresses the slotted distal end 407 of the barrel down against the spindle. Since the adaptor nut 405 renders the barrel 404 and the spiral groove tube 401 immobile relative to each other, the barrel 404, spindle 406 and spiral groove tube 401 all rotate together once the clamp nut 437 is secured.
FIGS. 12-15 relate to a further embodiment of the invention in which the distal portion, shown in FIG. 9A, of instrument 2b, shown in FIGS. 13A and 13B, has been modified. The purposes for the modifications are to permit the user to selectively lockout or prevent rotary motion of the jaws relative to the base and also to permit the user to easily and quickly replace one tip assembly with another tip assembly. Many of the elements are the same as or similar to those described above; these elements will not be described in detail but will be referred to with like reference numerals.
Tip carrier tube 8b is similar to tip carrier tube 8a but lacks internal threads 154 and has a circular hole 502 instead of slot 314. The purpose of hole 502 will be described below. Base extension 504 is secured to base 6b (see FIG. 14) and acts as an extension of base 6b. Base extension 504 includes an elongate cylindrical portion 506 and a bearing end 508. Bearing end 508 has internal threads 510 which engage external threads 512 formed at the distal end of base 6b. Accordingly, base extension 504 is a one piece, rigid extension of base 6b and thus does not rotate or move axially relative to the base. Bearing end 508 also helps to capture a set of ball bearings 162 between an internal shoulder 514 formed at bearing end 508 and annular shoulder 66a formed as a part of tip carrier tube 8b.
Due to the presence of sets of ball bearings 160, 162, tip carrier tube 8b can rotate relative to base 6b and base extension 504. This relative rotary motion can be prevented through the use of a serrated lockout collar 516. Serrated lockout collar 516 has a pair of internal cam surfaces 518 which lie opposite a pair of resilient lockout fingers 520. Lockout fingers 520 have cam bumps 522 formed at their distal ends which engage internal cam surfaces 518. Collar 516 is held in a fixed position axially along base extension 504 by a retainer band 524 which is press fit over cylindrical portion 506 of base extension 504. When lockout collar 516 is at the free movement position of FIG. 15A, lockout fingers 520 are spaced apart from tip carrier tube 8b so that tip carrier tube 8b can move freely within base extension 504. However, rotating lockout collar 516 in the direction of arrows 526 to the rotary motion lockout position of FIG. 15B causes lockout fingers 520 to press tightly against tip carrier tube 8b, thus frictionally securing the tip carrier tube to base extension 504 and thus to base 6b.
Axial drive 232 has a flanged drawbar 258a mounted to its distal end 263 by capturing flange 260 between sets of ball bearings 264, 266. Drawbar retaining nut 268 passes over flanged drawbar 258a and is threadably secured to the threads at end 263.
The distal end 530 of flanged drawbar 258a has a lateral hole 532 formed therethrough. Hole 532 is sized to accept a pin 534 to permit distal end 530 to be secured to the proximal end 536 of a bayonet receptacle 538. Receptacle 538 is a generally cylindrical member having a laterally extending hole 540 at its proximal end 536 sized for receipt of pin 534. Bayonet receptacle 538 has a pair of L-shaped slots 542. These L-shaped slots are used for engaging the tip assembly 10b as is discussed below.
Tip assembly 10b includes the rest of the structure shown in FIG. 12 and not yet discussed. Tip assembly 106 includes a tip tube 544 having an internally threaded distal end 546 to which tip coupler plug 148 is threadably secured. Tip assembly 10b also includes a fork 292a which is mounted to the interior of tip tube 544 through a press fit. Fork 292s is sized so that the proximal end 548 of fork 292a extends past proximal end 550 of tip tube 544. Fork 292a includes an axially extending slot 552 sized to accept a generally Z-shaped catch spring 554. The proximal end 556 of catch spring 554 is a radially extending tip which extends out past the outside surface of tip tube 544. The proximal end 548 of fork 292a is sized to fit within tip carrier tube 8b so that proximal end 556 of catch spring 554 can engage hole 502 formed in the tip carrier tube. Doing so retains tip tube 544 and fork 292a therewith in position both axially and radially relative to tip carrier tube 8b.
As discussed above, cam block 280a is mounted within wider gap 296a of fork 292a. Cam block 280a includes a cam block extension 558 which passes through and is guided by an internal shoulder 560 (see FIG. 13) formed within fork 292a. A bayonet pin 562 passes thorough a lateral bore 564 formed in the proximal end 566 of guide block extension 558. Pin 562 engages L-shaped slots 542 to permit tip assembly 10b to mounted to and disengaged from the remainder of the instrument.
Tip assembly 10b includes broadly tip tube 544, fork 292a, Cam block 280a, tip coupler plug 148 and jaws 28a, 28b. To mount an appropriate tip assembly 10b to the remainder of instrument 2b, the user inserts cam block extension 558 and proximal end 548 of fork 292a through the distal end 12b of tip carrier tube 8b until bayonet pin 562 contacts bayonet receptacle 538. Bayonet receptacle 538 is held in place by flanged drawbar 258a. The user then rotates tip assembly 10b until bayonet pin 562 becomes aligned with the axially extending portions of slots 542. The user than pushes tip assembly 10b axially and then twists the tip assembly until bayonet pins 562 engage the circumferentially extending portions of slots 542. When this occurs proximal end 556 of catch spring 554 becomes aligned with and moves into hole 502 thus securing tip assembly 10b in place. When it is desired to replace tip assembly 10b, for example if a different type of jaws 28a, 28b is needed, the user inserts a tool into hole 502 to depress proximal end 556 of catch spring 554. The user then rotates tip assembly 10b to align bayonet pin 562 with the axially extending portions of slots 542 and then pulls tip assembly 10b out of tip carrier tube 8b. The replacement tip assembly can then be mounted within tip carrier tube 8b. If during use the user desires to prevent tip assembly 10b from rotating relative to base 6b, the user merely rotates lockout collar 516 in the direction of arrows 526.
Other types of mechanisms can be used to keep tip carrier tube 8b from rotating relative to base 6b. Various types of clamps or thumbscrews could be used. With reference to FIG. 9B, rotary actuator trigger 78a could have a serrated surface along its length and base 6a could include some type of catch or keeper along slot 88a which could be actuated to engage the serrated surface along trigger 78a, thus locking the trigger in place.
Other modification and variation can be made to the disclosed embodiments without departing from the subject of the invention as defined in the following claims. For example, other methods for mounting a tip assembly to the remainder of the device could be used as well. It may be desired to spring bias loops 16, 18 away from one another and trigger 78 towards the position of FIG. 1.
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An endoscopic surgical instrument is designed for axial elongation by incorporating a manually operated mechanism which elongates the instrument upon manual rotation. The manually operated mechanism is joined to and supports a functional element at the tip of the instrument. Operation of the functional element at the distal tip of the instrument is achieved by manipulations at the proximal end of the instrument, and is not impaired by the extension. The user can lock the tip against rotary motion. The tip assembly is removably attached to the instrument, such as by using a bayonet-type locking element.
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BACKGROUND OF THE INVENTION
The invention relates to a gas lighter of a type comprising a tank, which is provided with a burner valve connected to a combustion space by a conduit, and also comprising an electrical ignition device.
Such lighters with battery ignition, friction-wheel ignition, or even spontaneous ignition are known. In one known form of lighter, the tank and a battery ignition device are arranged next to one another on a cylindrical axis. The outer lighter sleeve consists of two tubular parts of equal diameter which lie on a common axis and are connected releasably to one another. This form of construction has several considerable disadvantages. Firstly, to fill the tank, the lighter has to be dismantled, since the filler valve is arranged on the inside of the lighter and is accessible only in the dismantled state. Secondly, operation is extremely impractical, since the two tubular parts of the outer sleeve have to be displaced in opposition in an axial direction, which can only be performed with two hands. Thirdly, the lighter consists of a plurality of individual parts which are connected to one another by screwing or by means of exact fits. Consequently, manufacture and maintenance involve high costs. Fourthly, the tank is arranged between the ignition device and burner mouth, so that the high-voltage line to the ignition electrode has to be laid past the tank via a long connection which also needs to be made so that it can be broken by an expensive spring/ball contact.
SUMMARY OF THE INVENTION
To overcome the aforesaid disadvantages, the object of the invention is to provide a lighter which is simple to assemble and whose individual parts can be replaced easily even by a layman.
According to the invention, there is provided a gas lighter comprising a cylindrical tank provided with a burner valve, the burner valve being connected to a burner or combustion space by a conduit, an electrical ignition device mounted in a substantially semi-cylindrical holder and covered by a semi-cylindrical axially displaceable actuating member, the actuating member being provided with means for operating the ignition device and means for opening the burner valve, and a one-piece tubular sleeve surrounding and holding together the tank, the holder, and the actuating member, the sleeve having an aperture therein to permit manual movement of the actuating member.
To enable the burner valve to be easily fitted and adjusted in order to set the flame size, a valve operator preferably is arranged displaceably on the actuating member and engages with the burner valve. In a further preferred feature of the invention, a projection is molded on the casing of the tank in the region of the filler valve and in the assembled condition, a recess in the sleeve fits over the projection, thus enabling all the individual parts of the lighter to be located in the one-piece tubular outer sleeve without any screw connections. The individual parts are shaped so that they fit together by means of pin and slot like connections. The few individual parts which make up the lighter according to the invention can be assembled very quickly. A repair, also, can be carried out rapidly and without a tool even by a layman. Due to the arrangement of the filler valve in the base of the lighter, the tank can be filled without any assembly work. An operating member is preferably arranged so that a gripping portion for the hand remains underneath it, thus allowing comfortable handling.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described hereinafter in detail with respect to the accompanying drawings, in which:
FIG. 1 is a cross-section through a preferred embodiment of a gas lighter according to the invention;
FIG. 2 is an elevation from the right side of the lighter of FIG. 1 with an operating member removed;
FIG. 3 is a partly exploded view of the lower end of the lighter of FIGS. 1 and 2, to a fuel tank partially pulled out of a sleeve and to show a cap removed from the lower end of the fuel tank;
FIG. 4 is a section on line 4--4 of FIG. 2; and
FIG. 5 is an exploded view, in perspective, of a gas lighter according to an alternative embodiment of this invention and corresponding essentially to the preferred embodiment of FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
As shown in FIGS. 1 through 4 of the drawings, a preferred embodiment of a gas lighter according to this invention is characterized by a one-piece tubular sleeve 12, which is open at its opposite ends, and which telescopes over several other componens of the lighter so as to secure such other components in cooperative relation to each other, and so as to prevent disassembly of such other components except when the sleeve 12 has been removed. Preferably, the sleeve 12 is circular in internal cross-section, as shown in FIG. 4.
Among the other components secured by the sleeve as mentioned above is a unitary tank 1, which may be molded of a suitable plastic, and which holds butane or other suitable fuel. The tank 1 is provided with a filler valve 2, at its lower end as shown in FIG. 1, and with a burner valve 3, at its upper end as shown in FIG. 1.
The burner valve 3 is provided with a valve stem 3a, which is movable axially so as to open the burner valve 3 when pulled outwardly, and so as to close the burner valve 3 when pushed inwardly. The valve stem 3a is biased inwardly in a conventional way.
The burner valve 3 is connected, by means of a flexible conduit or tube 4, with a burner 5, which receives fuel from the tank 1 through the tube 4 whenever the burner valve 3 is opened, and thus whenever the valve stem is pulled outwardly. A piezo-electric ignition device 6 is arranged so as to be actuated by depression of a plunger 6a.
The plunger may be depressed, upwardly as shown in FIG. 1, so as to generate a spark between two electrodes (not shown) for ignition of fuel fed through the tube 4. The plunger 6a is biased, downwardly as shown in FIG. 1, by conventional means (not shown) within the ignition device 6.
At the upper end of the lighter as shown in FIG. 1, a cap 19 fits within the sleeve 12 and defines a flame orifice 20 of predetermined size. The cap 19 is affixed to a burner element 21 fitting into the sleeve 12 and defining a combustion zone. Air flow into the burner 5 is permitted by suitable orifices 23 (FIG. 2) in the sleeve 12. The filler valve 2, the burner valve 3, and the piezo-electric ignition device 6 are similar in structure and function to analogous components used in known gas lighters. Hence, further details of these components are not necessary to comprehension of this invention, and such details have been omitted from FIGS. 1 through 4 as described herein.
The tank 1 is molded of a suitable plastic or made otherwise so as to have a push fit within the sleeve 12, except at its lower end as shown in FIG. 1, where a cap 16 is affixed to the tank 1 so as to permit longitudinal displacement of the tank 1 only in one direction with respect to the sleeve 12. As shown in FIG. 1, the filler valve 2 is accessible through the cap 16 so as to permit the tank 1 to be filled in conventional manner but without prior removal of the sleeve 12.
The burner element 21 and the ignition device 6 are seated in a holder 8 which has a semi-cylindrical shape so as to fit within the sleeve 12, and which is connected to the tank 1, at the upper end of the tank 1 as shown in FIG. 1, so as to prevent relative displacement of the holder 8 and the tank 1 either rotationally or longitudinally, and so as to prevent disassembly of the holder 8 and the tank 1 when the sleeve 12 is telescoped over the several components secured by the sleeve 12. Thus, a non-circular neck 1a of the tank 1 fits transversely into a complementarily shaped slot in a transverse wall 8a of the holder 8, so as to prevent relative displacement of the holder 8 and the tank 1 rotationally. Also, a near surface on the tank 1 and an enlarged boss 1b on the neck 1a straddle the same wall 8a at margins of the slot, so as to prevent relative displacement of the holder 8 and the tank 1 longitudinally.
An actuating member 9 of semi-cylindrical shape fits slidably against the holder 8, so as to form a cylindrical subassembly comprising the holder 8 and the member 9 and having a push fit within the sleeve 12. Thus, the holder 8, the member 9, and the tank 1, which is connected to the holder 8 as described above, can be pushed into the sleeve 12 or pulled from the sleeve 12 as suggested by FIG. 3, for assembly or disassembly.
On its inner side, the member 9 is formed with an integral portion 10, which depresses the plunger 6a so as to actuate the ignition device 6 upon longitudinal displacement of the member 9 within the sleeve 12, along the holder 8, and toward the burner 5. Opposite displacement of the member 9, in a direction to which the member 9 is biased through the integral portion 10 by the aforesaid means (not shown) biasing the plunger 6a, is permitted by suitable relief on the tank 1.
Also on its inner side, the member 9 carries a valve operator 13, which is L-shaped as shown in FIG. 1, a transverse portion of which engages an annular element 3b carried by the valve stem 3a so as to open the burner valve 3 upon longitudinal displacement of the member 9 to actuate the ignition device 6, and which has a slot passing the integral portion 10 of the member 9 and allowing relative displacement of the member 9 and the valve operator 13 so as to enable the burner valve 3 to be easily fitted and adjusted in order to set the flame size.
The sleeve 12 is provided with an actuating aperture 11 through which an operating member 7 engages the actuating member 9. Plural connecting bosses on the operating member 7, on its inner side, snap into suitable receiving apertures 22 (FIG. 2) in the actuating member 9, so as to facilitate assembly and disassembly of the operating member 7 and the actuating member 9. The operating member 7 is assembled to the actuating member 9 after the sleeve 12 is telescoped over the several components secured by the sleeve 12, and after a cotter 18 to be described below is inserted.
The cotter 18, which is yoke-shaped, straddles the burner valve 3 between annular elements 13 and 1b on the burner valve 3 so as to limit longitudinal displacement of the actuating member 9 toward the tank 1. The cotter 18 is inserted, through the actuating aperture 11, after the sleeve 12 is telescoped over the several components secured by the sleeve 12, but before the operating member 7 is attached.
Near its lower end as shown in FIG. 1, the tank 1 is molded or provided otherwise with an integral projection 14, which is seated in a complementary recess 15 in the sleeve 12 and a complementary recess 17 in the cap 16, so as to assure rotational alignment of the sleeve 12 and the tank 1 for proper assembly of the lighter.
As shown in FIG. 5, an alternative embodiment of a gas lighter according to this invention is similar to the preferred embodiment shown in FIGS. 1 through 4 and described above, except for certain constructional details described below. The lighter of FIG. 5 is characterized by a one-piece tubular sleeve 100, which is open at its opposite ends 102 and 104, and which telescopes over several other components of the lighter so as to secure such other components in cooperative relation to each other, as in the lighter of FIGS. 1 through 4.
Among the other components secured by the sleeve 100 is a unitary tank 106, which is similar to the tank 1 of FIGS. 1 through 4, and which similarly is provided with a filler valve (not shown), at its right end as shown in FIG. 5, and with a burner valve 110. These valves are similar to analogous valves of FIGS. 1 through 4.
The burner valve 110 is provided with a valve stem 112, which is movable axially so as to open the burner valve 110 when pulled outwardly, and so as to close the burner valve 110 when pushed inwardly. The valve stem 112 is biased inwardly by conventional means (not shown) within the burner valve 110.
The burner valve 110 is connected, by means of a flexible tube 114, with a burner element 116, which receives fuel from the tank 106 through the tube 114 whenever the burner valve 110 is opened, and thus whenever the valve stem 112 is pulled outwardly. A conventional piezo-electric ignition device 118 is arranged so as to be actuated, by depression of a plunger 120 inwardly, leftwardly as shown in FIG. 5, so as to generate a spark between an electrode 122, which is connected to the ignition device 118 by an insulated lead 124, and another electrode 126, which is associated with a distal end 128 of the tube 114 and energized through a leaf spring 130 in a manner to be described below, for ignition of fuel fed through the distal end 128 of the tube 114. The plunger 120 is biased outwardly, rightwardly as shown in FIG. 5, by conventional means (not shown) within the ignition device 118.
The tank 106 is similar to the tank 1 of FIGS. 1 through 4 in that the tank 106 has a push fit within the sleeve 100, except at its right end as shown in FIG. 5, where a cap 132 is affixed to the tank 106 so as to permit longitudinal displacement of the tank 106 only in one direction with respect to the sleeve 100. The tank 106 also is similar in that the filler valve (not shown) is accessible through the cap 130 so as to permit the tank 106 to be filled in conventional manner but without prior removal of the sleeve 100.
The burner element 116 and the ignition device 118 are seated in a holder 140, which has a semi-cylindrical shape so as to fit within the sleeve 100. The burner element 116 has a circumferential groove 142 fitting into a complementary slot 144 in a transverse wall 146 of the holder 140, at the right end of the holder 140 as shown in FIG. 5, so as to prevent relative displacement of the burner enclosure 116 and the transverse wall 146 longitudinally.
As shown in FIG. 5, the burner element 116 is assymetrical rotationally, so as to fit over a transverse abutment 148 extending inwardly from the holder 140 and having a L-shaped channel 150, which accommodates the electrode 122 between the transverse abutment 148 and complementary surface portions 152 recessed in the burner element 116. Thus, the electrode 122 is secured therebetween, for proper orientation of the electrode 122 with respect to the electrode 126.
The electrode 126 comprises a conductive nozzle 154, which is fitted into the distal end 128 of the tube 114, and an annular contactor 156, which is mounted on the nozzle 154. Electrical contact is made between the contactor 156 and a contactor (not shown) on the left end of the ignition device 118 as shown in FIG. 5, through the leaf spring 130, which is made of conductive metal, and which is configured as shown in FIG. 5 so as to be biased away from the contractor 156 when the sleeve 100 is removed, and so as to be bent against the contactor 156 in a manner to be described below.
The ignition device 118 is seated within suitable abutments 160, 162, 164, and 166, which are integral with the holder 140, and which are arranged as shown in FIG. 5. The abutments 160 and 162, at the right end of the ignition device 118 as shown in FIG. 5, allow the tube 114 to pass therebetween, and allow the plunger 120 to operate, but limit depression of the plunger 120 upon engagement of an enlarged portion 168 of the plunger 120 with the abutments 160 and 162.
The holder 140 is similar to the holder 8 of the lighter of FIGS. 1 through 4 in that the holder 140 is connected to the tank 106, at the left end of the tank 106 as shown in FIG. 5, so as to prevent relative displacement of the holder 140 and the tank 106 either rotationally or longitudinally, and so as to prevent disassembly of the holder 140 and the tank 106 when the sleeve 100 is telescoped over the several components secured by the sleeve 100. Thus, a non-circular neck 170 of the tank 106 fits transversely into a complementarily shaped slot 172 in a transverse wall 174 of the holder 140, so as to prevent relative displacement of the holder 140 and the tank 106 rotationally. Also, a near surface 176 on the tank 106 and an enlarged boss 178 on the neck 160 straddle the wall 174 at margins of the slot 172, so as to prevent relative displacement of the holder 140 and the tank 106 longitudinally.
A captive end 180 of the leaf spring 130 is held against the contactor (not shown) on the left end of the ignition device 118 as shown in FIG. 5, by a resilient pad 182, which is held by transverse portions 184 and 186 of the abutments 164 and 166. A distal end 188 of the leaf spring 130 is adapted to engage the contactor 156, which is confined in a suitable slot 190 in a transverse wall 192 of the holder 140, when the leaf spring 130 is bent as described below.
An actuating member 200 of semi-cylindrical shape fits slidably against the holder 140, so as to form a cylindrical subassembly comprising the holder 140 and the member 200 and having a push fit within the sleeve. Thus, the holder 140, the member 200, and the tank 106, which is connected to the holder 140 as described above, can be pushed into the sleeve 100 or pulled from the sleeve 100 as suggested by FIG. 3, for assembly or disassembly.
On its inner side the member 200 is formed with an integral portion 202, which depresses the plunger 120 upon longitudinal displacement of the member 200 within the sleeve 100, along the holder 140, and toward the burner enclosure 116. Such displacement of the member 200 bends the leaf spring 130 so as to cause its distal end 188 to engage the contactor 156. Opposite displacement of the member 200, in a direction to which the member 200 is biased through the integral portion 202 by the aforesaid means (not shown) biasing the plunger 120, is permitted by suitable relief 204 on the tank 106.
Also on its inner side, the member 200 carries a valve operator 206, which is L-shaped as shown in FIG. 5, a transverse portion 208 of which engages an annular element 210 carried by the valve stem 112 so as to open the burner valve 110 upon longitudinal displacement of the member 200 to actuate the ignition device 118, and which has a slot 212 passing the integral portion 202 of the member 200 and allowing relative displacement of the member 200 and the valve operator 206 so as to enable the burner valve 110 to be easily fitted and adjusted in order to set the flame size. The valve operator 206 may be suitably connected to the member 200 so as to prevent disassembly of the valve operator 106 and the member 200.
The sleeve 100 is provided with an actuating aperture 220 through which an operating member 222 engages the actuating member 200. Plural connecting bosses 224, 226, and 228 on the operating member 7, on its inner side, snap into suitable receiving apertures 230 (not shown) in the actuating member 200, so as to facilitate assembly and disassembly of the operating member 222 and the actuating member 200. The bosses 224 and 228 are slotted, as shown in FIG. 5, so as to provide secure fits of the bosses 224 and 228 into the proper apertures. The operating member 222 is assembled to the actuating member 200, after the sleeve 100 is telescoped over the several components secured by the sleeve 12, and after a cotter 236 to be described below is inserted.
The cotter 236, which is yoke-shaped, straddles the burner valve 110 between annular elements 238 and 240 on the burner valve 110 so as to limit longitudinal displacement of the actuating member 200 toward the tank 106. The cotter 236 is inserted, through the actuating aperture 220, and through an aperture 260 in the actuating member 200, after the sleeve 100 is telescoped over the several components secured by the sleeve 100, but before the operating member 222 is attached.
Near its right end as shown in FIG. 5, the tank 106 is molded or provided otherwise with an integral projection 242, which is seated in a complementary recess 244 in the sleeve 100 and a complementary recess 246 in the cap 132, so as to assure rotational alignment of the sleeve 100 and the tank 106 for proper assembly of the lighter. In comparison with the projection 14 of the lighter of FIGS. 1 through 4, the projection 242 is rotated 90°, as a matter of choice.
A cap 250, which fits within the sleeve 100, and which is affixed to the burner element 116, provides a flame orifice (not shown) of a predetermined size, as in the lighter of FIGS. 1 through 4. Air flow into the burner element 116 is permitted by suitable orifices 252 in the sleeve 100.
In the lighter of FIG. 5, the tank 106, the burner valve 110, the tube 114, the electrode 126, and the filler valve (not shown) may be considered as one subassembly, the piezo-electric ignition element 118, the electrode 122, and the lead 124 may be considered as another subassembly, and the member 200 and the operator 206 may be considered another subassembly. These subassemblies and other components of the lighter may be assembled and disassembled easily and without tools.
In assembly of the lighter, the tank 106 is connected to the holder 140 and the electrode 126 is fitted into the slot 190 in the wall 192 of the holder 140, the ignition device 118 is seated in the holder 140 and the electrode 122 is placed in the channel 150, the leaf spring 130 is mounted by means of the resilient pad 182, and the burner element 116 is connected to the holder 140 so as to secure the electrode 122. Next, the member 200 is fitted onto the holder 140, so as to cause the transverse portion 208 of the operator 206 to engage the annular element 210, and the sleeve 100 is telescoped over the components as assembled thus far. Finally, the cotter 236 is inserted, and the member 222 is attached to the member 200.
In the assembled lighter, the burner element 116 shapes and controls a flame from fuel burner in a burner or combustion space, at the left end of the lighter as shown in FIG. 5. The burner or combustion space is intruded by the electrodes 122 and 126 and is fed with fuel from the tank 106 through the tube 114.
It is to be understood that the embodiments described above are exemplary and not intended to limit this invention as covered by the claims below.
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A gas lighter comprises a cylindrical tank having a filler valve and a burner valve connected to a burner by a conduit. An electrical ignition device is enclosed within a semi-cylindrical holder and a semi-cylindrical, axially displaceable actuating member, the actuating member being provided with means for operating the ignition device and means for opening the burner valve. The tank holder and actuating member are surrounded and held together by a one-part tubular sleeve having an aperture to permit manual movement of the actuating member.
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This application is a continuation of application Ser. No. 207,954 filed June 17, 1988, abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a coordinates input apparatus and, more particularly, to a coordinates input apparatus in which the vibration which is input by a vibration pen is detected by a plurality of sensors attached to a vibration propagating plate and the coordinates of the vibration pen on the vibration propagating plate are detected.
2. Related Background Art
Various kinds of input apparatuses have conventionally been known as coordinates input apparatuses. In this kind of apparatus, a coordinate system is set on a predetermined input surface, coordinates are input onto the input surface by an input device of a predetermined system, and the coordinate information on the coordinate system on the input surface is detected.
As a detecting system, there is known a system in which an input tablet is constituted by arranging a resistive film and a conductive film so as to face each other, and these films are touched by a writing tool such as finger, pen, or the like, or a system in which an input member consisting of an ultrasonic pen or the like is used, an ultrasonic vibration is input to an input tablet consisting of a vibration propagating plate or the like, and the coordinate values are detected from the vibration propagating time of the elastic wave which is generated on the tablet, or the like.
According to the latter system by the vibration propagation, a plurality of vibration sensors consisting of a plurality of piezoelectric elements or the like each for converting the mechanical vibration to the electric signal are attached to the glass plate constituting the tablet and the other vibration propagating plate in order to calculate the propagating time of the vibration which is propagated.
If the vibration input timing has already been known, by detecting the arrival timing of the vibration to the vibration sensor, the vibration propagating time to the sensor can be known. Since the vibration propagating speed on the vibration propagating plate is considered to be constant, the distance of the straight line between the vibration sensor and the input point can be obtained from the vibration propagating time. If the distance of the straight line between each sensor and the input point is known, the coordinate values of the input point can be determined by the theorem of three squares or the like.
According to such conventional systems, a method whereby the peak value of the detection signal waveform which is output from the vibration sensor is detected is used to decide the vibration detecting timing.
However, the vibration propagating plate has limited area and some reflected waves are certainly generated in the edge portion areas. Therefore, the vibration waveform which is input to the vibration sensor is the synthesis wave of the direct wave and the reflected waves.
In particular, the difference between the paths of the direct wave and reflected wave is very small in dependence on the positional relations among the coordinate input point, the sensor, and the edge portions of the vibration propagating plate. The detection signal waveform is largely distorted due to the interference between them. There is a problem such that a deviation occurs in the detection timing due to this influence and the coordinate detecting accuracy deteriorates.
There is also known a technique to support the edge portions of the vibration propagating plate by a vibration proofing material or the like in consideration of the foregoing point. However, it is difficult to perfectly eliminate the reflected waves. The area of the effective input surface is made smaller than the size of the vibration propagating plate, thereby allowing the direct wave and the reflected waves to reach the sensor with time lags, and the occurrence of the deviation of the detection timing due to the interference must be prevented.
Therefore, to assure the area of the necessary effective input surface, the area of the vibration propagating plate must be set to be a large value. There is a problem such that the size of the apparatus increases or the area of the effective input surface is limited.
SUMMARY OF THE INVENTION
It is the first object of the present invention to provide a coordinates input apparatus in which the vibration which is input by a vibration pen is detected by a plurality of sensors attached to a vibration propagating plate and the coordinates of the vibration pen on the vibration propagating plate are detected, wherein by providing drive control means for driving a vibrator of the vibration pen by a synthetic signal of a plurality of pulse trains whose phases differ, the drive pulse trains having different phases function so as to attenuate the attenuating vibration of the vibrator, so that even if the direct wave and reflected waves are interfered in the vibration sensor, the deviation of the peak value of the detection signal waveform is prevented, and the coordinate detection difference due to the difference between the vibration propagating times can be reduced.
The second object of the invention is to provide a coordinates input apparatus in which the detection waveform in a vibration sensor can be controlled into a desired shape by combining a plurality of pulses of different phases, and the detection timing or a special point on the waveform which is suitable to eliminate the influence of noise such as reflected waves on the vibration propagating plate and the like can be set.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an explanatory diagram showing an arrangement of an information input/output apparatus to which the present invention is applied;
FIG. 2A is an explanatory diagram showing a structure of a vibration pen in FIG. 1;
FIGS. 2B and 2C are waveform diagrams showing a vibrator drive waveform and a detection waveform in the invention, respectively;
FIGS. 2D and 2E are waveform diagrams showing conventional vibrator drive waveform and detection waveform, respectively;
FIG. 3 is a block diagram showing an arrangement of a calculation/control circuit in FIG. 1;
FIG. 4 is a waveform diagram showing detection waveforms for explaining the measurement of the distance between a vibration pen and a vibration sensor;
FIG. 5 is a block diagram showing an arrangement of a waveform detector in FIG. 1;
FIG. 6 is an explanatory diagram showing an arrangement of the vibration sensors; and
FIGS. 7A and 7B are waveform diagrams showing drive waveforms of vibrators in different embodiments, respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in detail hereinbelow on the basis of an embodiment shown in the drawings.
FIG. 1 shows an arrangement of an information input/output apparatus to which the invention is applied. In the information input/output apparatus of FIG. 1, coordinates are input by a vibration pen 3 to an input tablet consisting of a vibration propagating plate 8, thereby displaying an input image on a display 11 consisting of a CRT arranged overlappingly on the input tablet in accordance with the input coordinate information.
In FIG. 1, the vibration propagating plate 8 is made of an acrylic plate, glass plate, or the like and propagates the vibration which is propagated from the vibration pen 3 to three vibration sensors 6 attached to the corner portions of the plate 8. In this embodiment, the coordinates of the vibration pen 3 on the plate 8 are detected by measuring the propagating times of the ultrasonic vibrations propagated to the sensors 6 from the vibration pen 3 through the plate 8.
The peripheral portion of the vibration propagating plate 8 is supported by a reflection preventing material 7 such as silicone rubber or the like in order to prevent that the vibration propagated from the vibration pen 3 is reflected by the peripheral portion and returned toward the central portion.
The vibration propagating plate 8 is arranged on the display 11 such as a CRT (or liquid crystal display or the like) which can display an image by dots. The plate 8 displays an image by dots at the positions traced by the vibration pen 3. That is, the dots are displayed at the position on the display 11 corresponding to the coordinates of the pen 3 detected. The image consisting of elements such as point, line, or the like which was input by the vibration pen 3 appears after the track of the vibration pen as if it was written on a paper.
On the other hand, according to such a constitution, it is also possible to use an input system such that a menu is displayed on the display 11 and a desired item in this menu is selected by using the vibration pen, or an input system such that a prompt is displayed and the vibration pen 3 is touched to a predetermined position, or the like.
The vibration pen 3 to propagate the ultrasonic vibration to the vibration propagating plate 8 has therein a vibrator 4 consisting of a piezoelectric element or the like. The ultrasonic vibration generated by the vibrator 4 is propagated to the plate 8 through a horn portion 5 having a pointed tip.
FIG. 2A shows a structure of the vibration pen 3. The vibrator 4 attached in the pen 3 is driven by a vibrator driver 2. A drive signal of the vibrator 4 is supplied as a low-level pulse signal from a calculation/control circuit 1 in FIG. 1 and amplified at a predetermined gain by the vibrator driver 2 which can drive at a low impedance. Thereafter, the amplified drive signal is applied to the vibrator 4.
The electrical drive signal is converted into the mechanical ultrasonic vibration by the vibrator 4 and propagated to the vibration propagating plate 8 through the horn portion 5.
The oscillating frequency of the vibrator 4 is set to such a value that a plate wave can be generated in the vibration propagating plate 8 made of acryl, glass, or the like. On the other hand, when the vibrator is driven, a vibrating mode such that the vibrator 4 vibrates mainly in the vertical direction of the diagram for the plate 8 is selected. Further, by setting the oscillating frequency of the vibrator 4 to the resonant frequency of the vibrator 4, the vibration can be efficiently converted.
The elastic wave which is propagated to the plate 8 as mentioned above is the plate wave and has the advantage such that it is hardly influenced by scratches on the surface of the plate 8, obstacles or the like as compared with the surface wave or the like.
FIG. 2B shows a waveform of a drive signal of the vibrator 4. The vibrator 4 is driven by a pulse waveform as shown in the diagram, Hitherto, the vibrator 4 has been driven by a pulse train (1, 0, 1, ...) in which pulses are generated at regular intervals as shown in FIG. 2D. However, in the embodiment, the drive signal is constituted by a pulse train (1010100101000010) of the first group whose pulses are arranged at regular intervals and a subsequent pulse train of the second group whose phase is deviated by 180° . The pulse trains as shown in the diagram are input to the vibrator 4 every predetermined period of time.
Advantages which are obtained by use of such a drive signal will be explained in detail hereinbelow.
Returning to FIG. 1, the vibration sensors 6 attached to the corner portions of the vibration propagating plate 8 also consist of mechanical/electrical converting elements such as piezoelectric elements or the like. Each output signal of the three vibration sensors 6 is input to a signal waveform detector 9 and converted into an detection signal which can be processed by the calculation/control circuit 1 provided at the post stage. The calculation/control circuit 1 measures the vibration propagating times and detects the coordinate position of the vibration pen 3 on the vibration propagating plate 8.
The coordinate information of the vibration pen 3 detected is processed by the calculation/control circuit 1 in accordance with the output method by the display 11. That is, the calculation/control circuit controls the output operation of the display 11 through a display driver 10 on the basis of the input coordinate information.
FIG. 3 shows an arrangement of the calculation/control circuit 1 in FIG. 1. In this case, this diagram mainly shows structures of a driving system of the vibration pen 3 and a vibration detecting system by the vibration sensors 6.
A microcomputer 31 has therein an internal counter, an ROM, and an RAM. A drive signal generator 32 outputs drive pulses of a predetermined frequency to the vibrator driver 2 in FIG. 1 and is made operative by the microcomputer 31 synchronously with the circuit to calculate the coordinates.
A count value of a counter 33 is latched into a latch circuit 34 by the microcomputer 31.
On the other hand, the signal waveform detector 9 outputs timing information of the detection signal to measure the vibration propagating time for detection of the coordinates and signal level information for detection of writing pressure from the outputs of the vibration sensors 6. This timing information and this level information are input to a detection signal input port 35 and to an input/output port 37, respectively.
The timing signal which is input from the waveform detector 9 is input to the input port 35 and compared with the count value in the latch circuit 34 by a decision circuit 36. The result of the comparison is input to the microcomputer 31. That is, the vibration propagating time is represented as a latch value of the output data of the counter 33. The coordinates are calculated by the value of the vibration propagating time.
The output control process of the display 11 is executed through the I/O port 37.
FIG. 4 is a diagram for explaining a detection waveform which is input to the waveform detector 9 in FIG. 1 and the process for measuring the vibration propagating time based on the input detection waveform. In FIG. 4, a drive signal pulse 41 is applied to the vibration pen 3. The ultrasonic vibration propagated to the vibration propagating plate 8 from the pen 3 driven by such a waveform is propagated by the plate 8 and detected by the vibration sensors 6.
After the vibration progressed in the plate 8 for a time t g corresponding to the distance between the vibration input position to each vibration sensor 6, the vibration reaches the vibration sensor 6. In FIG. 4, reference numeral 42 denotes a signal waveform detected by the vibration sensor 6. In this embodiment, since the dispersive plate wave is used, the relation between an envelope 421 and a phase 422 of the detection waveform changes in accordance with the vibration propagating distance
It is now assumed that a group velocity of the envelope is V g and a phase velocity is V p . The distance between the vibration pen 3 and the vibration sensor 6 can be detected from the difference between the group velocity and the phase velocity.
First, when an attention is paid to only the envelope 421, its velocity is V g . When detecting a point on a certain special waveform, e.g., the peak as indicated at 43 in FIG. 4, the distance d between the pen 3 and the sensor 6 is obtained as follows by assuming that its vibration propagating time is t g .
d=V.sub.g ·t.sub.g (1)
This equation relates to one of the vibration sensors 6. The distance between each of the other two vibration sensors 6 and the vibration pen 3 can be also obtained by the same equation.
Further, to determine the coordinate values at a higher accuracy, the process based on the detection of the phase signal is executed. When it is assumed that the time interval until a special detection point of the phase waveform 422 in FIG. 4, for example, until the zero-cross point after passage of the peak point from the vibration applied timing is t p , the distance between the vibration sensor and the vibration pen can be obtained by
d=n·λ p +V p ·t p (2) where, λp denotes a wavelength of the elastic wave and n is an integer.
The integer n is shown as follows from the above equations (1) and (2).
n=[(V g ·t g -V p ·t p )/λ p +1/N] (3)
where, N is a real number other than 0 and a proper numerical value is used. For example, when N=2 and the wavelength is within ±1/2, n can be decided.
By substituting the value of n obtained as mentioned above for the equation (2), the distance between the pen 3 and the sensor 6 can be accurately measured.
To measure the two vibration propagating times t g and t p shown in FIG. 4, the signal waveform detector 9 can be constituted as shown in, e.g., FIG. 5.
In FIG. 5, the output signal of the sensor 6 is amplified to a predetermined level by a pre-stage amplifier 51.
The amplified signal is input to an envelope detector 52 and only the envelope of the detection signal is taken out. The timing of the peak of the extracted envelope is detected by an envelope peak detector 53. An envelope delay time detection signal T g of a predetermined waveform is formed from the peak detection signal by a signal detecter 54 constituted by a monostable multivibrator and the like. The signal T g is input to the calculation/control circuit 1.
A phase delay time detection signal T p is formed by a signal detector 58 from the timing of the T g signal and the original signal delayed by a delay time adjuster 57. The signal T p is input to the calculation/control circuit 1.
That is, the T g signal is converted into a pulse of a predetermined width by a monostable multivibrator 55. On the other hand, a comparison level generator 56 forms a threshold value to detect the t p signal in accordance with this pulse timing. Thus, the generator 56 forms a signal 44 having a level and a timing as shown in FIG. 4 and inputs to the detector 58.
Namely, the monostable multivibrator 55 and comparison level generator 56 are provided for allowing the phase delay time to be measured only for a constant period of time after the peak value of the envelope was detected.
An output signal of the generator 56 is input to the detector 58 consisting of a comparator or the like and compared with the delayed detection waveform as shown in FIG. 4. Thus, a t p detection pulse 45 is formed.
The foregoing circuit relates to one of the sensors 6. The same circuit is also provided for each of the other sensors 6. Assuming that the number of sensors is set to a general value h, the h detection signals of the envelope delay times T gl to T gh and the h detection signals of the phase delay times T pl to T ph are input to the calculation/control circuit 1, respectively.
The former half and the latter half of the envelope waveform 421 shown in FIG. 4 are asymmetrical. Particularly, the attenuating portion of the envelope waveform 421 is steep. Such an envelope is generated due to the constitution of the drive signal pulse 41 in FIGS. 2A and 4. The relation between the constitution of the drive pulse and the detection waveform will be described in detail hereinbelow.
In the calculation/control circuit in FIG. 3, the signals T gl to T gh and T pl to T ph are input from the input port 35. The count value of the counter 33 is latched into the latch circuit 34 by using the timing of each signal as a trigger signal Since the counter 33 starts counting synchronously with the driving of the vibration pen, the data indicative of the delay times of the envelope and phase are latched into the latch circuit 34, respectively.
As shown in FIG. 6, when three vibration sensors 6 are arranged at the corner positions S 1 to S 3 of the vibration propagating plate 8, the distances d 1 to d 3 of the straight lines from the position P of the vibration pen 3 to the positions of the sensors 6 can be obtained by the processes described in conjunction with FIG. 4. Further the coordinates (x, y) of the position P of the pen 3 can be further obtained by the calculation/control circuit 1 on the basis of the distances d 1 to d 3 from the theorem of three squares as follows.
x=X/2+(d.sub.1 +d.sub.2)(d.sub.1 -d.sub.2)/2X (4)
y=Y/2+(d.sub.1 +d.sub.3)(d.sub.1 -d.sub.3)/2Y (5)
where, X and Y represent distances along the X and Y axes between the sensors 6 at the positions S 2 and S 3 and the origin (position S 1 ).
The position coordinates of the pen 3 can be detected in a real-time manner as described above.
In this embodiment, as mentioned above, the vibrator 4 of the vibration pen 3 is driven by the drive signal consisting of two continuous pulse trains whose phases differ by 180° as shown in FIG. 2B.
FIGS. 2C and 2E show detection signal waveforms which are obtained by one of the vibration sensors 6 in the embodiment of FIG. 2B and in the conventional example of FIG. 2D, respectively. By comparing them, it will be understood that the drive pulse train in the embodiment in the period of time D of the detection vibration waveform more steeply attenuates.
This is because after the first pulse train in FIG. 2B reaches the detecting point, the subsequent pulse train whose phase is deviated by 180° and which arrives late functions so as to set off the vibration near the detecting point.
In the conventional detection waveform as shown in FIG. 2E, it gently attenuates in the period of time D and the level is also high. Therefore, if the attenuating portion is interfered by the reflected wave because of the reason such that the difference between the length of the direct wave path and the reflected wave path is small, it is also considered that a peak value larger than the peak value of the direct wave is caused.
However, according to the detection signal waveform as shown in FIG. 2C, the level in the attenuating portion is small and the attenuation is promptly executed. Therefore, even if the reflected waves are synthesized, a peak value larger than the direct wave is not caused, so that no deviation occurs between the vibration detection timings.
In this manner, the accurate vibration propagating time can be obtained and the high coordinate detecting accuracy can be held.
The possibility such that the detection waveforms of the reflected waves are synthesized in the portion of the high level of the detection waveform of the direct wave becomes higher as the effective input range of the vibration propagating plate 8 and the portion where the reflected wave occurs, for example, the boundary portion between the reflection preventing material 7 and vibration propagating plate 8 or the edge of the plate 8 is close. This is because the propagating path lengths of the reflected wave and of the direct wave are close.
Hitherto, in order to avoid the synthesis of the direct wave and reflected wave by increasing as large as possible the difference between the propagating path lengths of the reflected wave and direct wave as mentioned above, the effective input range has been limited by surrounding this range by the tablet cover or the like. However, according to the embodiment, the range of the time when no problem occurs even if the direct wave and the reflected wave which arrives later than the direct wave overlap can be enlarged, so that the effective input range can be allowed to approach the edge portion of the tablet, i.e., it can be widened. On the other hand, in the case of the same effective input area, the whole apparatus can be miniaturized or this means that the large effective input area can be obtained at the same size of the apparatus.
In the embodiment, as shown in FIG. 2B, the pulse trains of the first group (three pulse trains are shown in the case of FIG. 2B) and the subsequent pulse trains of the second group (two pulse trains are shown in the case of FIG. 2B) whose phases are deviated by 180° and whose number is nearly equal to that of the first group pulse trains are given to the vibrator 4 of the pen 3. However, in the case of giving the pulses of a plurality of groups having different phases to the vibrator, the constitution is not limited to the above constitution but can be arbitrarily set.
For example, as shown in FIG. 7A, the pulse trains of three groups whose phases are respectively deviated by 180° can be also used.
In the case of FIG. 7A, the drive signal of the vibrator of the vibration pen 3 is constituted by continuous pulse groups whose phases are respectively deviated by 180° in such a manner that the first group consists of two pulses, the second group consists of one pulse, and the third group consists of two pulses.
In the case of using such a drive signal, the detection waveform by one of the vibration sensors 6 is as shown in FIG. 7B. Namely, the envelope rises for the period of time A 1 by the pulses of the first group and the envelope attenuates by one pulse of the second group for the period of time D 1 . Subsequently, since the pulses of the third group whose phase is equal to that of the first group arrive before the waveform completely attenuates, the envelope peak P k occurs. Thereafter, the waveform attenuates for the period of time D 2 at the almost same speed as that in the conventional example of FIG. 2E.
According to such a detection waveform, the vibration detecting timing can be determined by detecting the inflection point of the envelope which occurs for the period of time D 1 . By the drive pulses as shown in FIG. 7A, the inflection point is provided in the front portion of the detection waveform as shown in FIG. 7B and the timing for the inflection point is set to the detecting point, thereby moving the vibration detecting timing to the position before the detection waveform. Due to this, the reflected wave which arrives at the detecting point later than the direct wave exerts an influence on the envelope waveform Thus, it is possible to further reduce a risk that a difference may occur in the vibration detecting timing.
The waveform attenuating speed or depth thereof for the attenuating period of time D 1 in FIG. 7B can be variously changed so as to be easily detected in accordance with the number of pulses which constitute the drive signal and whose phases differ or the like.
As is obvious from the above description, according to the invention, in a coordinates input apparatus in which the vibration which is input from the vibration pen is detected by a plurality of sensors attached to a vibration propagating plate and the coordinates of the vibration pen on the vibration propagating plate are detected, there is provided drive control means for driving a vibrator of the vibration pen by a synthetic signal of a plurality of pulse trains whose phases differ. Therefore, since the drive pulse trains having different phases function so as to attenuate the attenuating vibration of the vibrator, even if the direct wave and reflected waves are interfered in the vibration sensor, the deviation of the peak value of the detection signal waveform can be prevented and the coordinates detection error due to the difference of the vibration propagating times can be reduced. Accordingly, there is no need to limit the area of the effective input surface of the vibration propagating plate or to enlarge the whole apparatus to obtain the area of the necessary effective input surface as in the conventional apparatus in order to eliminate the influences by the reflected waves on the vibration propagating plate.
On the other hand, by combining the pulses having different phases, the detection waveform in the vibration sensor can be controlled into a desired shape and the detecting timing suitable to eliminate the influences by the noises of the reflected waves and the like on the vibration propagating plate or a special point on the waveform can be set. Therefore, it is possible to provide an excellent coordinates input apparatus which can detect the coordinates at a high accuracy and in which the reliability is high, the size is small, and the weight is light.
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There is provided a coordinates input apparatus comprising: a vibrator drive controller to output a vibrator drive signal obtained by synthesizing a plurality of pulse trains whose phases differ; a vibration pen to generate a vibration from a vibrator which generates the vibration in response to the vibration drive signal output from the vibrator drive controller; a vibration propagating plate made of a transparent acrylic or glass plate to propagate the vibration generated by the vibration pen; a plurality of vibration sensors, attached to the vibration propagating plate, for detecting the vibration generated by the vibration pen at a plurality of positions; and a coordinate value calculation/control circuit for calculating the vibration propagating times from the vibrations detected by the vibration sensors at a plurality of positions, thereby obtaining the coordinate values on the vibration propagating plate on which the vibration pen is located from the propagating times calculated. With this apparatus, the influences of noise such as reflected waves on the vibration propagating plate can be eliminated, so that the vibration detecting point or a special point on the waveform can be accurately set.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 11/405,021 filed on Apr. 14, 2006, which claims the benefit of U.S. Provisional Application No. 60/674,781 filed on Apr. 26, 2005. The disclosures of the above applications are incorporated herein by reference.
FIELD
[0002] The present teachings relate to compressors, and more particularly, to compressor warranty administration.
BACKGROUND
[0003] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
[0004] Compressors are used in a variety of industrial and residential applications to circulate refrigerant within a refrigeration, heat pump, HVAC, or chiller system (generically “refrigeration systems”) to provide a desired heating or cooling effect. In each application, it is desirable for the compressor to provide consistent and efficient operation to ensure that the refrigeration system functions properly. To this end, a compressor may be operated with an associated protection and control system.
[0005] The protection and control system may monitor operating signals generated by compressor or refrigeration system sensors and determine compressor or refrigeration system operating data. For example, the protection and control system may determine whether compressor or refrigeration system faults have occurred. Such data, however, may be lost when the protection and control system is turned off and/or when the protection and control system is no longer associated with the compressor.
[0006] A particular protection and control system may be compatible with a number of different compressor models and types of varying capacities. Traditionally, during installation it is necessary to load compressor specific data including, for example, numerical constants corresponding to the compressor model, type, and capacity into the protection and control system. Such compressor data is generally published by the compressor manufacturer, and used during refrigeration system design. The compressor data may be used during operation of the compressor by the protection and control system to control, protect, and/or diagnose the compressor and/or refrigeration system.
[0007] Loading the compressor data into the protection and control system is an additional step performed by the installer in the field. An error by the installer in the field while loading the compressor data may not be immediately apparent and may cause future compressor or refrigeration system operational problems. Further, if either the protection and control system, or the compressor, are replaced, the compressor data must be reloaded. In the field, such compressor data may be lost when the protection and control system and the compressor are no longer associated.
SUMMARY
[0008] A system is provided including a compressor having a first non-volatile memory connected to a module. The module has a processor and a second non-volatile memory. The first non-volatile memory is associated with the compressor. The module is selectively attached to the compressor and the processor is configured to access the first and second non-volatile memories.
[0009] In other features, the first non-volatile memory is embedded in the compressor or affixed to the compressor in a tamper-resistant housing.
[0010] In other features, the system further includes a connector block attached to the compressor to allow an electrical connection between an interior and an exterior of the compressor and the first non-volatile memory is embedded within the connector block.
[0011] In other features, the system further includes an RFID device that includes the first non-volatile memory.
[0012] In other features, the first non-volatile memory stores compressor specific data including at least one of: compressor model type data; compressor serial number data; compressor capacity data; compressor operating coefficient data comprising numerical constants associated with said compressor and used to calculate compressor operating data.
[0013] In other features, the first non-volatile memory stores compressor specific data including at least one of: compressor bill of materials data; compressor build sheet data; compressor build date data; compressor build plant data; compressor build shift data; compressor build assembly line data; compressor inspector data.
[0014] In other features, the first non-volatile memory stores compressor specific data including at least one of: compressor energy efficiency ratio data; compressor low voltage start data; compressor wattage data; maximum compressor electrical current data; compressor refrigerant flow data.
[0015] In other features, the first non-volatile memory stores compressor specific data including at least one of: compressor installation location data; compressor installation date data; compressor installer data; compressor purchase location data.
[0016] In other features, the first non-volatile memory stores compressor specific data including at least one of: compressor repair date data; compressor repair type data; compressor repaired parts data; compressor service technician data.
[0017] In other features, the first non-volatile memory stores compressor specific data including at least one of: suction pressure data; discharge pressure data; suction temperature data; discharge temperature data; electrical current data; electrical voltage data; ambient temperature data; compressor motor temperature data; compression element temperature data; compressor bearing temperature data; oil temperature data; compressor control data.
[0018] In other features, the first non-volatile memory stores refrigeration system data including at least one of: condenser temperature data; evaporator temperature data.
[0019] In other features, the first non-volatile memory stores compressor fault history data.
[0020] In other features, the system includes a communication device connected to the module to perform writing data to the first non-volatile memory and/or reading data from said first non-volatile memory.
[0021] Additionally, a compressor is provided having a non-volatile memory that stores manufacturing data related to the compressor.
[0022] In other features, the non-volatile memory is embedded in the compressor or affixed to the compressor in a tamper-resistant housing.
[0023] In other features, the compressor has a connector block attached to the compressor to allow an electrical connection between an interior and an exterior of the compressor, the non-volatile memory embedded within the connector block.
[0024] In other features, the compressor has an RFID device that includes the first non-volatile memory.
[0025] In other features, the manufacturing data includes at least one of: model type data of said compressor; serial number data of said compressor; capacity data of said compressor; operating coefficient data of said compressor comprising numerical constants associated with said compressor and used to calculate compressor operating data.
[0026] In other features, the manufacturing data includes at least one of: bill of materials data of said compressor; build sheet data of said compressor; build date data of said compressor; build plant data of said compressor; build shift data of said compressor; build assembly line data of said compressor; inspector data of said compressor.
[0027] In other features, the manufacturing data includes at least one of: energy efficiency ratio data of said compressor; low voltage start data of said compressor; wattage data of said compressor; maximum electrical current data of said compressor; refrigerant flow data of said compressor.
[0028] A method is provided for a compressor having a non-volatile memory. The method includes storing manufacturing data related to the compressor in the non-volatile memory.
[0029] In other features, the storing the manufacturing data related to the compressor in the non-volatile memory includes storing the manufacturing data in the non-volatile memory embedded in the compressor or affixed to the compressor in a tamper-resistant housing.
[0030] In other features, the storing the manufacturing data related to the compressor in the non-volatile memory includes storing the manufacturing data in the non-volatile memory embedded in a connector block attached to the compressor, the connector block allowing an electrical connection between an interior and an exterior of the compressor.
[0031] In other features, the storing the manufacturing data related to the compressor in the non-volatile memory includes storing the manufacturing data in the non-volatile memory in an RFID device.
[0032] In other features, the storing the manufacturing data includes storing at least one of: model type data of the compressor; serial number data of the compressor; capacity data of the compressor; operating coefficient data of the compressor comprising numerical constants associated with the compressor and used to calculate compressor operating data.
[0033] In other features, the storing the manufacturing data includes storing at least one of: bill of materials data of the compressor; build sheet data of the compressor; build date data of the compressor; build plant data of the compressor; build shift data of the compressor; build assembly line data of the compressor; inspector data of the compressor.
[0034] In other features, the storing the manufacturing data includes storing at least one of: energy efficiency ratio data of the compressor; low voltage start data of the compressor; wattage data of the compressor; maximum electrical current data of the compressor; refrigerant flow data of the compressor.
[0035] Additionally, a method is provided including accessing a first non-volatile memory associated with a compressor using a processor associated with at least one of a second non-volatile memory and an operating memory. The method also includes storing compressor data from the second non-volatile memory or the operating memory in the first non-volatile memory, and accessing the compressor data in the first non-volatile memory to evaluate compressor performance.
[0036] In other features, the accessing the first non-volatile memory includes accessing the first non-volatile memory embedded in the compressor or affixed to the compressor in a tamper-resistant housing.
[0037] In other features, method further includes electrically connecting an interior and an exterior of the compressor through a connector block wherein the accessing the first non-volatile memory includes accessing the first non-volatile memory embedded in the connector block.
[0038] In other features, the accessing the first non-volatile memory includes accessing the first non-volatile memory in an RFID device.
[0039] In other features, the storing the compressor data includes storing at least one of: compressor model type data; compressor serial number data; compressor capacity data; compressor operating coefficient data comprising numerical constants associated with said compressor and used to calculate compressor operating data.
[0040] In other features, the storing the compressor data includes storing compressor operating coefficient data comprising numerical constants associated with the compressor, the method further including calculating compressor operating data based on the compressor numerical constants.
[0041] In other features, the storing the compressor data includes storing at least one of: compressor bill of materials data; compressor build sheet data; compressor build date data; compressor build plant data; compressor build shift data; compressor build assembly line data; compressor inspector data.
[0042] In other features, the storing the compressor data includes storing at least one of: compressor energy efficiency ratio data; compressor low voltage start data; compressor wattage data; maximum compressor electrical current data; compressor refrigerant flow data.
[0043] In other features, the storing the compressor data includes storing at least one of: compressor installation location data; compressor installation date data; compressor installer data; compressor purchase location data.
[0044] In other features, the storing the compressor data includes storing at least one of: compressor repair date data; compressor repair type data; compressor repaired parts data; compressor service technician data.
[0045] In other features, the storing the compressor data includes storing at least one of: suction pressure data; discharge pressure data; suction temperature data; discharge temperature data; electrical current data; electrical voltage data; ambient temperature data; compressor motor temperature data; compression element temperature data; compressor bearing temperature data; oil temperature data; compressor control data.
[0046] In other features, the method further comprises storing refrigeration system data from the second non-volatile memory or the operating memory in the first non-volatile memory, wherein the storing refrigeration system data includes storing at least one of: condenser temperature data and evaporator temperature data.
[0047] In other features, the storing the compressor data includes storing compressor fault history data.
[0048] Additionally, a performance evaluation method for a compressor having a removable module including a processor and a first non-volatile memory is provided. The method includes accessing compressor data stored in a second non-volatile memory associated with the compressor and evaluating the compressor data to determine compressor performance.
[0049] In other features, the accessing the compressor data stored in the second non-volatile memory includes accessing the second non-volatile memory embedded in the compressor or affixed to the compressor in a tamper-resistant housing.
[0050] In other features, the method further includes electrically connecting an interior and an exterior of the compressor through a connector block wherein the accessing the compressor data includes accessing the second non-volatile memory embedded in the connector block.
[0051] In other features, the accessing the compressor data includes accessing the second non-volatile memory in an RFID device.
[0052] In other features, the accessing the compressor data includes accessing at least one of: compressor model type data; compressor serial number data; compressor capacity data; and compressor operating coefficient data comprising numerical constants associated with said compressor and used to calculate compressor operating data.
[0053] In other features, the accessing the compressor data includes accessing at least one of: compressor bill of materials data; compressor build sheet data; compressor build date data; compressor build plant data; compressor build shift data; compressor build assembly line data; compressor inspector data.
[0054] In other features, the accessing the compressor data includes accessing at least one of: compressor energy efficiency ratio data; compressor low voltage start data; compressor wattage data; maximum compressor electrical current data; compressor refrigerant flow data.
[0055] In other features, the accessing the compressor data includes accessing at least one of: compressor installation location data; compressor installation date data; compressor installer data; compressor purchase location data.
[0056] In other features, the accessing the compressor data includes accessing at least one of: compressor repair date data; compressor repair type data; compressor repaired parts data; compressor service technician data.
[0057] In other features, the accessing the compressor data includes accessing at least one of: suction pressure data; discharge pressure data; suction temperature data; discharge temperature data; electrical current data; electrical voltage data; ambient temperature data; compressor motor temperature data; compression element temperature data; compressor bearing temperature data; oil temperature data; compressor control data.
[0058] In other features, method further includes accessing refrigeration system data from the second non-volatile memory associated with the compressor, including accessing at least one of: condenser temperature data; evaporator temperature data.
[0059] In other features, the accessing the compressor data includes accessing compressor fault history data.
[0060] Additionally, a system is provided that includes a remote module operable to communicate with a plurality of local modules. Each local module includes a processor and a first non-volatile memory associated with the processor. The processor communicates with the first non-volatile memory and a second non-volatile memory associated with a compressor. The remote module includes a database of information copied from the second non-volatile memory.
[0061] In other features, the second non-volatile memory is embedded in the compressor or affixed to the compressor in a tamper-resistant housing.
[0062] In other features, the system further includes a connector block attached to the compressor to allow an electrical connection between an interior and an exterior of the compressor, wherein the second non-volatile memory is embedded within the connector block.
[0063] In other features, the system further includes an RFID device that includes the second non-volatile memory.
[0064] In other features, the local module is selectively attached to the compressor.
[0065] In other features, the local module is one of: a compressor protection and control system, a system controller, or a hand-held computing device.
[0066] In other features, the local module and the remote module are connected via a computer network.
[0067] In other features, the compressor has a connector block attached to the compressor to allow an electrical connection between an interior and an exterior of the compressor wherein the second non-volatile memory is embedded within the connector block.
[0068] In other features, the second non-volatile memory stores compressor specific data including at least one of: compressor model type data; compressor serial number data; compressor capacity data; compressor operating coefficient data comprising numerical constants associated with the compressor and used to calculate compressor operating data. The local module communicates the compressor specific data to the remote module for storage in the database.
[0069] In other features, the second non-volatile memory stores compressor specific data including at least one of: compressor bill of materials data; compressor build sheet data; compressor build date data; compressor build plant data; compressor build shift data; compressor build assembly line data; compressor inspector data. The local module communicates the compressor specific data to the remote module for storage in the database.
[0070] In other features, the second non-volatile memory stores compressor specific data including at least one of: compressor energy efficiency ratio data; compressor low voltage start data; compressor wattage data; maximum compressor electrical current data; and compressor refrigerant flow data. The local module communicates the compressor specific data to the remote module for storage in the database.
[0071] In other features, the second non-volatile memory stores compressor specific data including at least one of: compressor installation location data; compressor installation date data; compressor installer data; compressor purchase location data. The local module communicates the compressor specific data to the remote module for storage in the database.
[0072] In other features, the second non-volatile memory stores compressor specific data including at least one of: compressor repair date data; compressor repair type data; compressor repaired parts data; compressor service technician data. The local module communicates the compressor specific data to the remote module for storage in the database.
[0073] In other features, the second non-volatile memory stores compressor specific data including at least one of: suction pressure data; discharge pressure data; suction temperature data; discharge temperature data; electrical current data; electrical voltage data; ambient temperature data; compressor motor temperature data; compression element temperature data; compressor bearing temperature data; oil temperature data; compressor control data. The local module communicates the compressor specific data to the remote module for storage in the database.
[0074] In other features, the second non-volatile memory stores refrigeration system data including at least one of: condenser temperature data; evaporator temperature data. The local module communicates the refrigeration system data to the remote module for storage in the database.
[0075] In other features, the second non-volatile memory stores compressor fault history data. The local module communicates the compressor fault history data to the remote module for storage in the database.
[0076] Additionally, a compressor performance evaluation method is provided for a remote module in communication with a plurality of local modules. The method includes, for each local module, accessing a first non-volatile memory associated with a compressor using a processor associated with a second non-volatile memory or an operating memory, and storing compressor data from the second non-volatile memory or the operating memory in the first non-volatile memory. The method also includes, for the remote module, accessing the compressor data in each first non-volatile memory, storing the compressor data in a database, and accessing the database to evaluate compressor performance.
[0077] In other features, the accessing the compressor data in each first non-volatile memory includes accessing the compressor data with a computer network connection.
[0078] In other features, for the remote module, the accessing the compressor data includes accessing at least one of: compressor model type data; compressor serial number data; compressor capacity data; compressor operating coefficient data comprising numerical constants associated with said compressor and used to calculate compressor operating data.
[0079] In other features, for the remote module, the accessing the compressor data includes accessing at least one of: compressor bill of materials data; compressor build sheet data; compressor build date data; compressor build plant data; compressor build shift data; compressor build assembly line data; compressor inspector data.
[0080] In other features, for the remote module, the accessing the compressor data includes accessing at least one of: compressor energy efficiency ratio data; compressor low voltage start data; compressor wattage data; maximum compressor electrical current data; compressor refrigerant flow data.
[0081] In other features, for the remote module, the accessing the compressor data includes accessing at least one of: compressor installation location data; compressor installation date data; compressor installer data; compressor purchase location data.
[0082] In other features, for the remote module, the accessing the compressor data includes accessing at least one of: compressor repair date data; compressor repair type data; compressor repaired parts data; compressor service technician data.
[0083] In other features, for the remote module, the accessing the compressor data includes accessing at least one of: suction pressure data; discharge pressure data; suction temperature data; discharge temperature data; electrical current data; electrical voltage data; ambient temperature data; compressor motor temperature data; compression element temperature data; compressor bearing temperature data; oil temperature data; compressor control data.
[0084] In other features, for each local module, the method further includes storing refrigeration system data from the second non-volatile memory or the operating memory in the first non-volatile memory. For the remote module, the method further includes accessing the refrigeration system data in each first non-volatile memory and storing the refrigeration system data in the database.
[0085] In other features, for the remote module, the accessing the refrigeration system data includes accessing at least one of condenser temperature data and evaporator temperature data.
[0086] In other features, for the remote module, the accessing the compressor data includes accessing compressor fault history data.
[0087] Additionally, a method is provided including providing a warranty for a compressor having a non-volatile memory; receiving a claim under the warranty; examining data stored in the non-volatile memory; and responding to the claim based on the examining.
[0088] In other features, the examining the data stored in the non-volatile memory includes examining the non-volatile memory embedded in the compressor or affixed to the compressor in a tamper-resistant housing.
[0089] In other features, the examining the data stored in the non-volatile memory includes examining the non-volatile memory embedded in a connector block that provides an electrical connection between an interior and an exterior of the compressor.
[0090] In other features, the examining the data stored in the non-volatile memory includes examining the non-volatile memory in an RFID device.
[0091] In other features, the providing the warranty includes providing terms by which the compressor may be replaced or repaired.
[0092] In other features, the providing the warranty includes defining misuse of the compressor. The responding to the claim includes determining compressor misuse based on the data and the warranty and refusing to replace or repair the compressor when the data indicates compressor misuse.
[0093] In other features, the defining misuse includes defining an allowable operating range for the compressor and wherein the determining compressor misuse includes comparing the data with the allowable operating range.
[0094] In other features, the defining the allowable operating range includes defining at least one of: a refrigerant level range, a refrigerant pressure range, a refrigerant temperature range, an electrical current range, an electrical voltage range, an ambient temperature range, a compressor motor temperature range, a compressor bearing temperature range, and an oil temperature data range.
[0095] In other features, the providing the warranty includes defining misuse of the compressor. The responding to the claim includes determining compressor misuse based on the data and the warranty and replacing or repairing the compressor when the data does not indicate compressor misuse.
[0096] In other features, the responding to the claim includes refusing to replace or repair the compressor when the data indicates that the compressor is functioning.
[0097] In other features, the responding to the claim includes determining a cause of a compressor malfunction based on the examining and repairing the compressor based on the determining.
[0098] In other features, the examining the data includes examining at least one of: compressor model type data; compressor serial number data; compressor capacity data; compressor operating coefficient data comprising numerical constants associated with the compressor and used to calculate compressor operating data.
[0099] In other features, the examining the data includes examining at least one of: compressor bill of materials data; compressor build sheet data; compressor build date data; compressor build plant data; compressor build shift data; compressor build assembly line data; compressor inspector data.
[0100] In other features, the examining said data includes examining at least one of: compressor energy efficiency ratio data; compressor low voltage start data; compressor wattage data; maximum compressor electrical current data; compressor refrigerant flow data.
[0101] In other features, the examining the data includes examining at least one of: compressor installation location data; compressor installation date data; compressor installer data; compressor purchase location data.
[0102] In other features, the examining the data includes examining at least one of: compressor repair date data; compressor repair type data; compressor repaired parts data; compressor service technician data.
[0103] In other features, the examining the data includes examining at least one of: suction pressure data; discharge pressure data; suction temperature data; discharge temperature data; electrical current data; electrical voltage data; ambient temperature data; compressor motor temperature data; compression element temperature data; compressor bearing temperature data; oil temperature data; compressor control data.
[0104] In other features, the examining the data includes examining at least one of: condenser temperature data; evaporator temperature data.
[0105] In other features, the examining the data includes examining compressor fault history data.
[0106] Additionally, a method is provided including: warranting a compressor having a non-volatile memory; receiving a claim for repair or replacement of the compressor; accessing data stored in the non-volatile memory to determine if the compressor was misused; denying the claim for repair or replacement of the compressor when the data indicates that the compressor was misused; and replacing or repairing the compressor when the data indicates that the compressor was not misused.
[0107] In other features, the accessing the data in the non-volatile memory includes accessing the non-volatile memory embedded in the compressor or affixed to the compressor in a tamper-resistant housing.
[0108] In other features, the accessing the data in the non-volatile memory includes accessing the non-volatile memory embedded in a connector block that provides an electrical connection between an interior and an exterior of the compressor.
[0109] In other features, the accessing the data in the non-volatile memory includes accessing the non-volatile memory in an RFID device.
[0110] In other features, the warranting the compressor includes defining compressor misuse.
[0111] In other features, the defining the compressor misuse includes defining an allowable operating range for the compressor.
[0112] In other features, the defining said allowable operating range includes defining at least one of: a refrigerant level range, a refrigerant pressure range, a refrigerant temperature range, an electrical current range, an electrical voltage range, an ambient temperature range, a compressor motor temperature range, a compressor bearing temperature range, and an oil temperature data range.
[0113] In other features, the accessing the data stored in the non-volatile memory to determine if said compressor was misused includes comparing the data with the allowable operating range and determining if the compressor was misused based on the comparison.
[0114] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
[0115] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
[0116] FIG. 1 is perspective view of a compressor in accordance with the present teachings;
[0117] FIG. 2 is a perspective view of a protection and control system attached to a compressor in accordance with the present teachings;
[0118] FIG. 3 is an exploded view of a protection and control system and compressor memory system in accordance with the present teachings;
[0119] FIG. 4 is a schematic view of processing circuitry of a protection and control system in accordance with the present teachings;
[0120] FIG. 5 is a flow chart illustrating a data access control algorithm for a compressor memory system in accordance with the present teachings;
[0121] FIG. 6 is a schematic representation of a compressor information network in accordance with the present teachings; and
[0122] FIG. 7 is a flow chart illustrating a warranty administration method in accordance with the present teachings.
DETAILED DESCRIPTION
[0123] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
[0124] As used herein, the terms module, control module, and controller refer to one or more of the following: an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, or other suitable components that provide the described functionality. Further, as used herein, computer-readable medium refers to any medium capable of storing data for a computer. Computer-readable medium may include, but is not limited to, CD-ROM, floppy disk, magnetic tape, other magnetic medium capable of storing data, memory, RAM, ROM, PROM, EPROM, EEPROM, flash memory, punch cards, dip switches, or any other medium capable of storing data for a computer.
[0125] A protection and control system may monitor operating signals generated by compressor or refrigeration system sensors and determine compressor or refrigeration system operating data. The protection and control system may be of the type disclosed in assignee's commonly-owned U.S. patent application Ser. No. 11/059,646, Publication No. 2005/0235660, filed Feb. 16, 2005, the disclosure of which is incorporated herein by reference. It is understood, however, that other suitable systems may be used.
[0126] The protection and control system may be communicatively connected with a compressor and physically mounted on, but separable from, the compressor. The protection and control system may be physically separable from the compressor insofar as the protection and control system may be removed or separated from the compressor. For example, the protection and control system may be replaced or repaired and then re-mounted to the compressor.
[0127] The protection and control system may monitor compressor and/or refrigeration system operation. For example, the protection and control system may determine an operating mode for the compressor and may protect the compressor by limiting operation when conditions are unfavorable. Further, the protection and control system may determine whether compressor or refrigeration system faults have occurred.
[0128] With reference to FIGS. 1 to 4 , a compressor 10 may include a generally cylindrical hermetic or semi-hermetic shell 12 with a welded or bolted cap 14 at a top portion and a welded or bolted base 16 at a bottom portion. The cap 14 and base 16 may be fitted to the shell 12 such that an interior volume 18 of the compressor 10 is defined. The cap 14 may be provided with a discharge fitting 20 , while the shell 12 may similarly be provided with an inlet fitting 22 , disposed generally between the cap 14 and base 16 . A terminal box 30 with a terminal box cover 32 may be attached to the shell 12 .
[0129] The terminal box 30 may house the protection and control system 34 . The protection and control system 34 may have a protection and control system housing 36 and an integrated circuit (IC) 40 with processing circuitry 42 . The protection and control system 34 may be a module and may include processing circuitry 42 that may include a data processing means such as a processor 39 . The processor 39 may be a central processing unit (CPU) or a microprocessor. The processing circuitry 42 may also include random access memory (RAM) 41 and a non-volatile memory such as a read only memory (ROM) 43 . Alternatively, the data processing means may be implemented by an application specific integrated circuit (ASIC), an electronic circuit, a combinational logic circuit, or other suitable components that may provide the described functionality.
[0130] The protection and control system 34 may operate according to an operating program stored in the ROM 43 to perform in the manner described herein. The RAM 41 may function as an operating memory during operation of the protection and control system 34 . The processor 39 may access both the RAM 41 and the ROM 43 .
[0131] The protection and control system housing 36 may include a housing face portion and a housing back portion. The protection and control system 34 may be matingly received by a hermetic connector block 44 , which may be located within the terminal box 30 and fixedly attached to the compressor shell 12 . The hermetic connector block 44 may maintain the sealed nature of the compressor 10 while allowing power to be delivered to the compressor motor (not pictured) via power leads 47 as discussed in more detail below. The protection and control system 34 may be mounted to the shell 12 using two studs 49 which may be welded or otherwise fixedly attached to the shell 12 .
[0132] An embedded memory system 45 may include non-volatile memory 46 embedded within the compressor 10 . Specifically, the non-volatile memory 46 may be embedded within the hermetic connector block 44 . The memory system 45 may include a memory connector 48 interfaced with the non-volatile memory 46 . The non-volatile memory 46 may contain compressor specific data including, for example, numerical constants corresponding to the compressor model, type, and capacity. In other words, certain compressor pedigree or identification information may be stored in the non-volatile memory 46 .
[0133] The non-volatile memory 46 may remain within the hermetic connector block 44 , attached to or embedded within the compressor 10 , for the entire operating life of the compressor 10 . In this way, the compressor specific data may remain with the compressor 10 , stored in the non-volatile memory 46 , regardless of whether the compressor is moved to a different location, returned to the manufacturer for repair, or used with different protection and control systems.
[0134] Alternatively, the non-volatile memory 46 may be located in a tamper resistant housing elsewhere on or in the compressor 10 . For example, the non-volatile memory 46 may be in a tamper resistant housing embedded within, or attached to, the terminal box 30 or terminal box cover 32 . In addition, the non-volatile memory 46 may be embedded within the compressor shell 12 , or located within the interior volume 18 of the compressor 10 . The non-volatile memory 46 may be located at any suitable location that is generally inaccessible to a user, customer, repair person, or technician. The tamper resistant housing may include a sealed package affixed, adhered, or otherwise attached to the compressor 10 and configured to house the non-volatile memory in an inaccessible and protected fashion. Additionally, the non-volatile memory 46 may be located within the protection and control system 34 on the processing circuitry 42 .
[0135] The non-volatile memory 46 may be in-molded in a compressor component, such as the hermetic connector block 44 , the terminal box 30 , terminal box cover 32 , or other suitable component for maintaining the non-volatile memory 46 in an isolated and tamper resistant manner. In this way, the non-volatile memory 46 may remain with the compressor 10 for the operating life of the compressor 10 .
[0136] The hermetic connector block 44 may be configured with a memory connector 48 in communication with the non-volatile memory 46 . In this way, the non-volatile memory 46 may be read from, or written to, via the memory connector 48 . As shown in FIG. 3 , the memory connector 48 may include an eight pin connector. However, other connector configurations, with more or less pins, may be utilized. Further, other types of connectors may be utilized to provide an interface with the non-volatile memory 46 . For example, a serial data connection may be made with the non-volatile memory 46 . Additionally, a wireless device, such as an RFID device, may be used to communicate with the non-volatile memory 46 .
[0137] As an example, the non-volatile memory 46 may be a two kilobyte or four kilobyte erasable programmable read-only memory (EPROM) chip or an electrically erasable programmable read only memory (EEPROM) chip. Other types and other sizes of memory devices may be utilized including flash memory, magnetic media, optical media, or other non-volatile memory suitable for storing data. Additionally, an RFID device may be used. The RFID device may include non-volatile memory and may wirelessly communicate data. If an RFID device is used, the memory connector 48 may be a wireless data communication device that allows communication with the RFID device.
[0138] As used herein, non-volatile memory is intended to refer to a memory in which the data content is retained when power is no longer supplied to it, such as an EPROM or EEPROM. Additionally, non-volatile memory may include a traditionally volatile memory configured with an independent source of power to retain data. For example, a random access memory (RAM) may be used and embedded within the compressor 10 with an independent power source, such as a battery with an expected battery life that is greater than the expected operating life of the compressor 10 .
[0139] The IC 40 may be configured with an IC connector 50 such that the IC connector 50 may be matingly received by the memory connector 48 when the protection and control system 34 is attached to the hermetic connector block 44 . In this way, the non-volatile memory 46 may communicate with the processing circuitry 42 , via the IC connector 50 and memory connector 48 . The processing circuitry 42 may read from or write to the non-volatile memory 46 .
[0140] The non-volatile memory 46 may receive electrical power from the memory connector 48 and the protection and control system 34 , or other device, connected to the memory connector 48 . In this way, the non-volatile memory 46 may not require an independent source of electrical power.
[0141] The hermetic connector block 44 may be configured with three power leads 47 electrically connected to internal compressor components, such as a compressor motor (not pictured). Three phase electrical power may be delivered to the compressor 10 via a power cord 52 received by the terminal box 30 . The power cord 52 may attach to the ends of three conductive studs 54 via apertures 37 on the face of the housing 36 . The hermetic connector block 44 may receive the three conductive studs 54 . Each of the three conductive studs 54 may be connected to a separate phase of the three phase electrical power delivered by the power cord 52 . At installation, the power leads 47 may be bent over, such that an aperture in each of the power leads may receive one of the three conductive studs 54 . In this way, the power leads 47 may be electrically connected to the conductive studs 54 and three phase electrical power may be delivered from the power cord 52 to the compressor 10 .
[0142] While delivery of three phase power to the compressor 10 is described, the compressor 10 may alternatively receive single phase power. Further, any other system for delivery of power to the compressor 10 may be used.
[0143] Electrical power may also be delivered to the IC 40 and processing circuitry 42 via at least one of the conductive studs 54 . While the compressor 10 may be powered by three phase electrical power, the IC 40 and processing circuitry 42 may be powered by single phase electrical power from one of the conductive studs 54 .
[0144] The processing circuitry 42 may receive various operating signals generated by compressor or refrigeration system sensors. The processing circuitry 42 may determine or derive compressor or refrigeration system operating data. Electrical current sensors 56 may be located on the IC 40 and may generate electrical current signals corresponding to the amount of electrical current drawn by the compressor 10 . The processing circuitry 42 may monitor the electrical current signals generated by the electrical current sensors 56 . Generally, the level of current drawn by the compressor corresponds to the present load on the compressor. The current drawn by the compressor 10 generally increases as the present load on the compressor 10 increases.
[0145] Additional compressor sensors may be located within the compressor shell 12 . Such internal compressor sensors may include a motor temperature sensor, a discharge line temperature sensor, a suction pressure sensor, or the like. Another hermetic connector block 58 may be fixedly attached to the compressor shell 12 and configured with conductive terminals 60 connected to each of the internal compressor sensors. The processing circuitry 42 may receive the operating signals generated by the internal compressor sensors. The processing circuitry 42 may also receive additional operating signals from additional system or compressor sensors external to the compressor 10 . Based on the various operating signals, the processing circuitry 42 may determine an operating mode for the compressor 10 , and may generate compressor or system fault alerts.
[0146] The protection and control system 34 may be configured with a communication terminal 62 connected to the processing circuitry 42 via an aperture 63 in the face of the housing 36 . The communication terminal 62 may be connected to a number of network/communication devices. As described in more detail below and in assignee's commonly-owned U.S. patent application Ser. No. 11/059,646, Pub. No. 2005/0235660, filed Feb. 16, 2005, the communication terminal 62 may be operable to connect to, and communicate with, a handheld computing device, a system controller, or other suitable communication/network device.
[0147] Referring now to FIG. 5 , a flow chart illustrating a data access control algorithm for a memory system 45 is shown. Prior to normal operation, the memory system 45 may be loaded with initialization data, including compressor specific data, in grouped steps 98 . When the compressor 10 is initially assembled and configured with the memory system 45 , the compressor manufacturer, for example, may load the memory system 45 with compressor specific data in step 100 . The compressor specific data may include manufacturing data related to the specific compressor 10 with which the memory system 45 is associated.
[0148] For example, the initialization data may include the compressor model, serial number, and capacity size. A bill of materials, i.e., the list of part numbers of all the individual components of the compressor, may also be loaded into the memory system 45 . The build sheet, or sequence of operations carried out in the assembly of the compressor 10 , may also be loaded. Data as to the date, shift, plant, assembly line, and inspector that built and inspected the compressor 10 may also be loaded.
[0149] Compressor specific data may also include test data information loaded into the memory system 45 by the compressor manufacturer. Test data may include an energy efficiency ratio, which relates the compressor's BTU's/Hr to input power in watts. Test data may also include a low voltage start number, which represents the lowest line voltage at which the compressor 10 may start. Test data may also include a Watts number, related to the electrical power that may be input to the compressor 10 . Test data may also include a maximum current drawn by the compressor 10 at maximum load. Test data may also include the amount of refrigerant flow under given test conditions.
[0150] Compressor specific data may also include compressor operating coefficient data. Each compressor 10 is associated with certain compressor-specific numerical constants to be utilized by the protection and control system 34 when making certain calculations and operating data determinations. For example, as disclosed in assignee's commonly-owned U.S. patent application Ser. No. 11/059,646, Pub. No. 2005/0235660, filed Feb. 16, 2005, the protection and control system 34 may utilize compressor-specific numerical constants to calculate data about other refrigeration system components.
[0151] For example, the protection and control system 34 may determine a condenser temperature or an evaporator temperature based on the following formula:
P = C 0 + ( C 1 × T COND ) + ( C 2 × T EVAP ) + ( C 3 × T COND 2 ) + ( C 4 × T COND × T EVAP ) + ( C 5 × T EVAP 2 ) + ( C 6 × T COND 3 ) + ( C 7 × T EVAP × T COND 2 ) + ( C 8 × T COND × T EVAP 2 ) + ( C 9 × T EVAP 3 ) , ( 1 )
[0152] where P is compressor power, T COND is condenser temperature, T EVAP is evaporator temperature, and C 0 to C 9 are constants that are specific to the particular compressor model and capacity size.
[0153] Likewise, the protection and control system may determine compressor capacity according to the following equation:
X = Y 0 + ( Y 1 × T COND ) + ( Y 2 × T EVAP ) + ( Y 3 × T COND 2 ) + ( Y 4 × T COND × T EVAP ) + ( Y 5 × T EVAP 2 ) + ( Y 6 × T COND 3 ) + ( Y 7 × T EVAP × T COND 2 ) + ( Y 8 × T COND × T EVAP 2 ) + ( Y 9 × T EVAP 3 ) ( 2 )
[0154] where X is compressor capacity, T COND is condenser temperature, T EVAP is evaporator temperature, and Y 0 to Y 9 are constants that are specific to the particular compressor model and size.
[0155] Numerical constants C 0 to C 9 and Y 0 to Y 9 , which are traditionally published by the compressor manufacturer and loaded into the protection and control system 34 at the time the compressor is installed in the field, may be preloaded into the nonvolatile memory 46 of the memory system 45 by the compressor manufacturer at the time the compressor 10 is built. In this way, compressor specific data is loaded into the memory system 45 , thereby decreasing the installation burden on the installer in the field and minimizing the chance for installation error.
[0156] Information related to the specific refrigeration system connected to a compressor may be loaded into the memory system 45 by a system manufacturer in step 102 . For example, the refrigeration system manufacturer may receive a compressor 10 configured with a memory system 45 that has been loaded by the compressor manufacturer with compressor specific information. The refrigeration system manufacturer may then use the compressor 10 as a component in a refrigeration system, with, for example, an evaporator or a condenser. The refrigeration system manufacturer may load refrigeration system information, such as component model and serial number information for the system components, such as the evaporator and the condenser, into the memory system 45 .
[0157] Installation data may be loaded into the memory system 45 by the installer at the time the compressor is installed at the field location in step 104 . As discussed above, the memory system 45 is configured with a memory connector 48 . In the field, the memory system 45 may be accessed by the installer with a handheld device connected directly to the memory connector 48 . Alternatively, the memory system 45 may be accessed after the protection and control system 34 is installed. In such case, the installer may access the memory system 45 with a handheld device connected to the communication terminal 62 of the protection and control system 34 . In this way, the memory system 45 is accessible by the handheld device, via the communication terminal 62 , processing circuitry 42 , IC connector 50 , and memory connector 48 . Similarly, the memory system 45 may be accessed by other devices connected to the communication terminal 62 of the protection and control system 34 .
[0158] Installation data loaded into the memory system 45 may include the installation location, the installation date, the installer's name, and the dealer from whom the compressor 10 was purchased. Additionally, subsequent to installation, if the compressor 10 is ever serviced, service information, such as a service description and a listing of replacement parts, may be loaded into the memory system 45 at that time in the same manner.
[0159] With continuing reference to FIG. 5 , once the compressor 10 has been installed at the field location, the compressor 10 may enter normal operation in grouped steps 106 . A normal operating cycle is generally shown in grouped steps 106 . During normal operation 106 , the compressor 10 may perform operating functions at step 108 . During normal operation, the protection and control system 34 may monitor operating signals generated by compressor or refrigeration system sensors and may generate compressor or refrigeration system operating data. The protection and control system 34 may determine an operating mode for the compressor 10 and may determine whether compressor or refrigeration system faults have occurred.
[0160] During normal operation, the protection and control system 34 may write operating data to the memory system 45 in step 110 . In a memory system 45 that utilizes a two kilobyte or four kilobyte EEPROM, operating data for the most recent two to three minutes of operation may be stored in the memory system 45 . Longer periods of operating data may be stored if a memory system 45 with a greater amount of memory is utilized. When the memory allocated for storing operating data is full, the protection and control system 34 may write over the oldest operating data first. Additionally, the protection and control system 34 may partition the memory allocated for storing operating data into discrete segments. When the allocated memory is full, the oldest segment may be erased and rewritten with more recent operating data.
[0161] Operating data written to the memory system 45 may include any number of predetermined signals and parameters monitored or generated by the compressor, the refrigeration system, or the protection and control system 34 . For example, operating data may include data related to electrical current drawn, compressor voltage, ambient temperature, discharge line temperature, intake line temperature, compressor motor winding temperature, compression element temperature, bearings temperature, oil temperature, discharge line pressure, intake line pressure, and the like. Operating data may also include refrigeration system data such as condenser temperature and evaporator temperature. Operating data may also include refrigeration system communication inputs, such as a refrigeration system call for cooling or heating, a defrost command, or the like.
[0162] Fault history data may also be stored in the memory system 45 . The protection and control system 34 may determine whether a compressor 10 or system fault has occurred in step 112 . When a fault has occurred, the protection and control system 34 may update the fault history data in the memory system 45 in step 114 . Fault history data may include information related to the date, time, and type, of the most recent faults. For example, a seven day fault history may be stored in the memory system 45 . Information related to the last fault, such as the last fault compressor motor temperature, last fault voltage or current, last fault oil level, last fault number of cycles, etc. may be stored in the memory system 45 .
[0163] In step 116 , the protection and control system 34 may determine whether a request for memory system data has been made by a device connected to the communication terminal 62 . When a device requests data from the memory system 45 , via the communication terminal 62 , the protection and control system 34 may retrieve the requested data from the memory system 45 and provide it to the requesting device via the communication terminal 62 in step 118 . The protection and control system 34 then loops back to step 108 .
[0164] In this way, compressor specific data, system data, installation data, and operating data may be stored in the memory system 45 and accessed by the protection and control system 34 , as well as any other devices connected to the protection and control system 34 via the communication terminal 62 .
[0165] The data stored in the memory system 45 may be used to evaluate compressor performance or refrigeration system performance. For example, by examining the data stored in the memory system 45 , operating data may be evaluated in light of the compressor model and capacity size, as well as in light of the installation location of the compressor. The data stored in the memory system 45 may provide insight into the operation of the compressor based on the various factors that may affect performance and based on the specific compressor specifications. In this way, the data stored in the memory system 45 may provide evaluation assistance when a new compressor is being considered for purchase or when a new compressor is being designed.
[0166] The protection and control system 34 may be connected to a network via the communication terminal 62 . In such case, the memory system 45 may be accessible to other devices connected to the network. The compressor specific data, system data, and operating data may then be used to diagnose the compressor, diagnose the refrigeration system, schedule maintenance, and evaluate compressor warranty claims.
[0167] Referring now to FIG. 6 , a compressor information network 150 is shown. The protection and control system 34 , or multiple protection and control systems 34 , may be connected to a network. The protection and control systems 34 may be connected to the network via the communication terminal 62 which is communicatively connected to the processing circuitry 42 . Alternatively, the protection and control system 34 may be connected to the network via a system controller 152 , such as a refrigeration system controller. Further, the protection and control system 34 may be connected to the network via a hand-held computing device 154 or other suitable network device. The protection and control system 34 may be connected to the internet 158 via a wired or wireless internet connection 160 .
[0168] The protection and control system 34 may be connected to a computer network such as the internet 158 . Further, the protection and control system 34 may be connected to a database server 156 via the internet 158 . The database server 156 may be a module configured to communicate with the protection and control systems 34 and with a computer information database stored in a computer readable medium 164 . In this way, the contents of the memory system 45 may be accessible to other devices connected to the network, including the database server 156 .
[0169] The database server 156 may collect information from the memory system 45 via a memory system information transaction initiated by the database server 156 , the protection and control system 34 , the system controller 152 , the hand-held computing device 154 , or other network device. The database server 156 may build a comprehensive compressor information database based on the contents of multiple memory systems 45 connected to the network. In this way, the database server 156 may store compressor information including compressor identity, location, operation history, service history, fault history, fault data, etc., for multiple compressors 10 connected to the network and located in multiple locations around the world.
[0170] The compressor information database may be used to evaluate compressor operation. The database may be used to improve future compressor or refrigeration system design, to improve field service technician training, and/or to determine trends related to certain similar environmental conditions. The database server information may also be used for asset management purposes as a tool to analyze sales and marketing activities. The information may also be shared with system manufacturers or system component manufacturers to assist in the design and implementation of refrigeration systems and system components. In other words, the database may provide compressor operation data, tied to geographic installation locations, compressor type and capacity, and other compressor specification data.
[0171] Referring now to FIG. 7 , information stored in the memory system 45 may be used during the administration of compressor warranty claims. A compressor may be covered by a manufacturer's warranty. The warranty may include the terms by which the compressor may be replaced or repaired. The warranty often includes an expiration date. Further, the warranty may include terms by which compressor misuse and other warranty voiding events may be defined. The warranty voiding events may include certain misuse circumstances. For example, the warranty may include certain acceptable operating ranges, including a refrigerant level range, a refrigerant pressure range, a refrigerant temperature range, an electrical current range, an electrical voltage range, an ambient temperature range, a compressor motor temperature range, a compressor bearing temperature range, and an oil temperature data range. If the user ignores a misuse condition for a certain period of time, and allows the compressor to operate under misuse circumstances, the warranty may be voided.
[0172] When a compressor fault occurs, a claim may be made under the compressor manufacturer's warranty that the compressor 10 , or a compressor component, is defective or otherwise subject to repair by the manufacturer under the terms of the warranty. In such case, the owner of the compressor may return the compressor 10 to the manufacturer with the claim indicating the reason for return. The compressor manufacturer may receive the warranty claim information in step 200 .
[0173] When a compressor 10 with a memory system 45 is returned to the manufacturer under a warranty claim, the manufacturer may access the memory system 45 and examine the fault history data and operating data. The data from the memory system 45 may be retrieved by the compressor manufacturer in step 202 . By examining the memory system data, the manufacturer may confirm whether the compressor 10 was the cause of the fault. When refrigeration system data is stored in the memory system 45 , the manufacturer may determine that a non-compressor system component, like a condenser or evaporator, was the cause of the fault complained of in the warranty claim. In such case, the manufacturer may be able to quickly determine that the compressor 10 is not defective or in need of repair. The compressor manufacturer may determine whether a non-compressor component was at fault in step 204 .
[0174] In addition, by examining the contents of the memory system 45 , the manufacturer may be able to determine whether a warranty voiding event occurred prior to the compressor fault. For example, the memory system 45 may reveal that a low refrigeration fluid condition was ignored for a period of time prior to the compressor fault occurring. In such case, the manufacturer may determine that the warranty claim is void due to the compressor owner ignoring the low refrigeration fluid condition. The compressor manufacturer may determine whether a warranty invalidating event has occurred in step 206 .
[0175] When the compressor 10 is at fault in step 204 , and when a warranty invalidating event has not occurred in step 206 , the compressor manufacturer may repair or replace the compressor under the terms of the warranty in step 208 . When a non-compressor component is at fault, or when a warranty invalidating event has occurred in steps 204 or 206 , the compressor manufacturer may notify the compressor owner in step 210 .
[0176] When the memory system 45 is remotely accessible to the manufacturer via a network device, as discussed above, the manufacturer may be able to make a preliminary warranty claim determination prior to the compressor 10 being sent to the manufacturer. For example, prior to disconnecting the compressor from the system for return to the manufacturer, the compressor owner may simply notify the manufacturer that it believes a problem covered by the warranty has occurred. The manufacturer may then access the compressor's memory system 45 and examine the memory system data to make a preliminary determination as to the warranty claim. When a warranty voiding event has occurred, the manufacturer may inquire with the compressor owner as to the occurrence of the warranty voiding event. The compressor manufacturer may also be able to make a preliminary determination as to whether the problem complained of originated with a non-compressor component fault. Such a preliminary determination will save time and money previously lost due to unnecessary or uncovered warranty claims.
[0177] During a warranty claim, if it is determined that the compressor failure was due to failure of a non-compressor system component based on the data contained in the memory system 45 , this data can be shared with the manufacturer of the non-compressor system component. In this way, data and information may be shared with other component and system manufacturers to assist in the administration of their warranty claims as well.
[0178] The description is merely exemplary in nature and, thus, variations are intended to be within the scope of the teachings. Such variations are not to be regarded as a departure from the spirit and scope of the teachings.
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A warranty administration method includes providing a warranty for a compressor having a non-volatile memory, receiving a claim under the warranty, examining data stored in the non-volatile memory, and responding to the claim based on the examining.
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This invention generally relates to an all-terrain vehicle; and more particularly relates to a novel and improved vehicle having a tractive roller assembly to increase the mobility, traction and versatility of the vehicle.
BACKGROUND AND FIELD OF THE INVENTION
A number of approaches have been taken in the construction and design of all-terrain vehicles for military, commercial or recreational use. Typically, however, these vehicles utilize the basic construction of a military tank in which tracks located on either side of the vehicle body can be driven in unison or separately controlled in speed to effect steering of the vehicle both in a forward and reverse direction. In the past, the track-type vehicles have suffered definite limitations insofar as their use over rough terrain is concerned, since they tend to lose traction in passing over ditches, craters, ridges and other obstacles. Moreover, the unbalancing effect in passing over sharp ridges or other obstacles is such as to cause loss of control and possible damage to the vehicle or injury to the operator. Similarly, these vehicles have difficulty in negotiating soft or muddy terrain.
In the past, it has been proposed to equip vehicles of the type described with roller assemblies or auxiliary propulsion elements at opposite ends. For example, U.S. Pat. No. 3,477,535 to H. M. Wyatt discloses a vehicle having front and rear roller assemblies which can be lowered to raise the vehicle off the ground but has limited traction or propulsion capabilities insofar as being able to advance the vehicle over rough terrain is concerned. U.S. Pat. No. 2,489,349 to C. C. White is directed to a track-type vehicle equipped with disks mounted on articulated frames at opposite ends of the vehicle. The vehicle can be propelled only by the disk assemblies; however, owing to the construction of the disks, their utilization as a means of propulsion is largely limited to hard, smooth ground and not to rough or soggy terrain. U.S. Pat. No. 3,570,604 to P. L. Allard similarly is directed to a vehicle provided with spiked wheels journaled on hingedly mounted frames at the front and rear ends of the vehicle. The frames can be lowered until the wheels engage the ground and the vehicle body is elevated whereupon an independent hydraulic motor must be activated to rotate the wheels and advance the vehicle, its principal intended use being as a lawn conditioning element. Other representative approaches and designs relating to articulated roller assemblies mounted at opposite ends of a vehicle are disclosed in U.S. Pat. Nos. 1,358,575 to E. Rimailho; 2,012,090 to N. Straussler; 2,959,201 to R. G. Le Tourneau; 3,054,467 to E. W. Seiler; 3,057,319 to E. A. Wagner; 3,417,832 to J. J. Ziccardi; 3,698,499 to R. V. Albertson; 3,794,121 to D. A. Drozak; 3,820,497 to N. G. Konijn; and 4,157,877 to B. R. Lee.
Thus to my knowledge no one has devised an all-terrain vehicle provided with articulated tractive roller assemblies mounted at opposite ends of the vehicle which is capable of negotiating rough or muddy terrain while possessing both digging and ground clearing capabilities.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide for a novel and improved all-terrain vehicle which is characterized by its stability and traction in negotiating rough or uneven terrain.
Another object of the present invention is to provide in a track-type vehicle for novel and improved tractive roller assemblies at opposite ends of the vehicle which can be operated in unison with or independently of the main propulsion system of the vehicle.
It is a further object of the present invention to provide for novel and improved tractive roller assemblies adaptable for use with track-type vehicles which are capable of serving both as a means of added propulsion while at the same time being capable of being operated independently as digging and ground clearing implements as well as to permit lifting or lowering of the vehicle.
It is an additional object of the present invention to provide in an all-terrain vehicle for novel and improved tractive roller assemblies at opposite ends of the vehicle which will cooperate in advancing the vehicle over rough or soft terrain, can be used independently as the main ground-engaging drive of a vehicle in grading, digging and filling and further to provide a means of leveling the vehicle in traversing steep grades.
In accordance with the present invention, a track-type vehicle comprises a vehicle body with ground-engaging tracks mounted on the vehicle body for advancing the vehicle, front and rear arm members pivotally mounted for swinging movement through a vertical plane relative to the front and rear ends of the vehicle body, each set of arms carrying generally cylindrical, cleated roller assemblies, each said roller assembly having a generally cylindrical housing and a plurality of fingers eccentrically mounted within the housing for extension and retraction with respect to the housing as the housing is rotated. Means are drivingly connected to the housing for rotating the housing, and pivot control means are drivingly connected to each of the sets of arms at opposite ends of the vehicle to control pivotal movement of the arms and attached cylindrical cleated members. Preferably, each cylindrical cleated member is provided with conical end sections including eccentrically mounted fingers which will undergo extension and retraction through said conical end sections in response to rotation of the cylindrical cleated member. Moreover, each arm is preferably defined by a crank pivotally connected to a support housing, the pivotal movement of each being independently controlled by hydraulic cylinders so as to achieve maximum mechanical advantage and precise control over the movement of the cleated cylindrical members.
In the preferred form of the present invention, the tractive roller assemblies are employed in combination with a track-type vehicle in which a common hydraulic control circuit is capable of rotating the track members as well as independently controlling the pivotal movement and rotation of the tractive roller assemblies. In this way, propulsion of the vehicle in a forward or reverse direction is accomplished by the combination of the tracks and tractive roller assemblies, the degree of pressure exerted by the tractive roller assemblies against the ground being controlled by the hydraulic cylinders attached to the arm members for the tractive roller assemblies and which pressure can be independently controlled by the operator as well as being automatically controlled in response to sensing the angle of the vehicle in traversing steep grades. Accordingly, greater force can be imparted to the trailing roller assembly than to the leading roller assembly in ascending a steep grade while imparting a greater pressure on the leading roller than on the trailing roller in descending a grade. In a stationary or rest position, increased pressure can be applied in rotating the roller assemblies, for example, to carry out digging, grading or fill operations. The retractable arrangement of the fingers enables them to be self-cleaning, for example, in advancing through heavy underbrush or when being used as a tool.
Other objects, advantages and features of the present invention will become more readily appreciated and understood when taken together with the following detailed description in conjunction with the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a preferred form of all-terrain vehicle in accordance with the present invention;
FIG. 2 is a side elevational view of the vehicle illustrated in FIG. 1 and further illustrating pivotal movement of the tractive roller assemblies with respect to the vehicle;
FIG. 3 is an enlarged view, partially in section and in more detail of one of the tractive roller assemblies;
FIG. 4 is an exploded view of a cylindrical pleated member for one of the tractive roller assemblies;
FIG. 5 is another exploded view in more detail illustrating the eccentric mounting elements of one of the cylindrical cleated members;
FIG. 6 is another exploded view illustrating one of the eccentric mounting elements for the fingers in a conical end section of a cylindrical cleated member;
FIG. 7 is a side view in more detail illustrating the range of pivotal movement of one of the tractive roller assemblies with respect to the vehicle;
FIG. 8 is a sectional view of one of the pivotal mounting booms and gear drives for a tractive roller assembly; and
FIG. 9 is a flow diagram of a preferred form of hydraulic control circuit for the vehicle of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring in detail to the drawings, there is illustrated in FIGS. 1 and 2, a tractive roller assembly 10 mounted at the front and rear ends of a conventional track-type vehicle generally designated at V. Conventionally, the vehicle includes an operator section F mounted on a conventional body designated at B and driven by tracks T on opposite sides of the body of the vehicle.
In the preferred form, each roller assembly is comprised of a central, generally cylindrical section 11 and opposed generally conical end sections 12. As shown in FIG. 3, the center and end sections 11 and 12 are assembled together on a common dead axle 14 traversing the length of the sections 11 and 12. In the center section, the dead axle 14 has a hollow, elongated eccentric portion 15, and stepped-down eccentric portions 17 are affixed to opposite ends of the dead axle 14 within each of the conical sections 12.
As shown in FIGS. 1 to 3, a center housing 20 is separated from end housings 21 by pivotal gear housings 22, each gear housing having a semi-circular end 23 and an opposite, generally rectangular end 24. At the rectangular end 24, one corner 25 is pivotally connected to the lower link arm 26 of a pair of closely-spaced, parallel bell cranks 27 which are pivotal in unison about a hub 28 at one end of the vehicle V. Another corner 25' is connected to the piston rod or plunger 30 at the end of hydraulic cylinder 31 which is secured to the other link arm 26' of the spaced parallel bell cranks 27. A longer cylinder 32 has its piston end 33 attached to the vertical arm 26' of bell cranks 27, the cylinder 32 being mounted for rotational movement about a fixed pivotal axis 33 on the vehicle V.
Referring specifically to FIG. 3, there is associated with each gear housing 22 a drive gear 34 at opposite ends of drive shaft 35, the drive shaft 35 extending from a common motor 36 in housing 37. Housing 37 is joined at opposite ends to the bell cranks 27, and opposite ends of the drive shaft 35 are supported in bearings in one of the bell cranks 27 at each end of the housing 37. Each drive gear 34 intermeshingly engages an idler gear 38 which drives a double or split gear 39 supported on bearings on either side of a fixed web or plate 40. The plate 40 is keyed to the dead axle 14 while the split gears 39 are journaled on the dead axle and are drivingly connected into the center and end housings 20, 21 of the tractive roller assembly 10 so as to synchronously rotate the center and end housings.
In the center housing 20, each of a series of doughnut-shaped or annular support rings 41 is mounted on an inner cylindrical bushing 42 and a radially outwardly extending thrust plate 43 on one side of the ring 41, as shown in FIG. 5. The opposite side of each ring 41 has a circular bearing member 56 partially inserted in an annular groove on the side of the ring so as to bear against the next adjacent thrust plate 43. As noted, the support rings 41 and intervening thrust plates 43 are disposed in juxtaposed relation across the length of the support housing 20 and are journaled on the eccentric support section 15, the center ring 41 being interposed between a pair of rings 43 as shown in FIG. 6. Each support ring 41 has a radially directed finger 44 mounted thereon for outward radial projection through an aligned opening 45 in the outer housing, each opening having a surrounding bushing element 46 through which the finger extends. Each finger is preferably in the form of an elongated solid or rigid rod or spike. As the outer housing 20 is rotated, it will cause the fingers to follow rotation of the housing 20 as the annular support rings 41 are rotated around the eccentric portion 15. This will cause the fingers to progressively advance from a retracted position as shown, for example, at 44a to a projected position as shown in at 44b through the outer housing wall through each one-half revolution, then through the remainder of its revolution will return to a retracted position. The fingers are staggered with respect to one another preferably by spacing them 90° with respect to adjacent fingers so that the fingers will alternately and progressively advance into the projected position as they are rotated around the eccentric member.
The conical end sections 12 are correspondingly provided with annular support rings 48 upon which are mounted fingers 49, each support ring 48 mounted on an eccentric surface of progressively reduced diameter, as defined by the stepped-down portions 17, which proceed outwardly from the gear housing 22 to the extreme end of each conical section 12. Specifically, each support ring 48 is supported on an eccentric surface by an inner circumferential bushing plate 52 and a side thrust plate 53, each thrust plate 53 and attached bushing 52 being affixed by means of suitable fasteners 50 into the side of a stepped surface. In this way, the support rings are journaled by the bushings 52 on the stepped portions and are free to slide with respect to the thrust plate of the next larger stepped portion as well as with respect to the wall of the housing so as to reduce friction therebetween.
The reduced end extremity of each conical end section 12 has a thickened end portion 54 which rides on the outer race of a bearing 55, the inner race of the bearing 55 being affixed to the end of the dead axle 14. The enlarged end of the eccentric portion 17 is connected to an end plate 60 which bears against the end wall 62 of the housing 21. In the same manner as described with respect to the center section, the fingers 49 are staggered with respect to one another with an approximate spacing of 90° therebetween so that they can alternately and progressively advance into projected or extended positions as they are rotated about the eccentric portion 17.
From FIGS. 1 and 2, it will be noted that a pair of cylinders 31 and 32 are mounted on opposite sides of the body of the vehicle both at the front and rear ends to regulate the vertical movement of the tractive roller assemblies between a raised position, as shown in dotted form in FIG. 2, to an angle which, although not shown, will project the assemblies 10 downwardly beneath the tracks T and in this way be capable of effectively lifting the vehicle off of the tracks T in the manner illustrated in more detail in FIG. 7.
A preferred form of hydraulic control circuit is illustrated in FIG. 9 wherein a reservoir 80 includes a conventional strainer 81, filter 82 and cooler 83 in the return line, shown in dotted form, to the reservoir. A variable displacement motor 84 is provided for each track of the vehicle V, and each tractive roller assembly at the front and rear has its own variable displacement motor 36. Under normal driving conditions, the variable displacement double pumps 86' and 86" are associated with auxiliary charging vane pump 86, a Model TA1919V20, manufactured and sold by Sperry Vickers of Troy, Mich. which supplies fluid under pressure to the track drive motors 84 via forward and reverse lines 70 and 72. Thus, each pump 86' and 86" has a swash plate control and will operate to deliver fluid under pressure through control valves 87 to drive the motor 84 in one direction; or can be reversed to direct fluid under pressure through the motor 84 in the opposite direction. The priority flow valves 87 are connected into one side of each motor 45 so as to give prioritize flow to the motors 36 when more pressure is needed for the cylinders 31 and 32, such as, for use of the tractive roller assemblies in digging operations.
Each pump 86' and 86" delivers fluid under pressure to the roller drive motors 36, this fluid being directed through control valve 88 and pressure line 89 in a forward direction and through pressure line 90 in the reverse direction. A second control valve 92 is shunted across or bridges the intake and discharge sides of the motor 36 to place the motor in the free-wheeling position.
Additional energy is stored in the accumulator 94 for each forward and reverse drive circuit and, upon demand for acceleration or increased velocity, will automatically deliver additional fluid under pressure through dump valve 95 and via branch lines 75, each containing a check valve 76, and through each of the pumps 86' and 86" to each of the track drive motors 84. Fluid returns to the accumulator 94 via line 96 in order to charge it up rapidly when there is no demand on pump 100 and there is excess pressure in the system.
The pump 100 is a pressure compensated fixed displacement pump which is operative to supply fluid under pressure directly from the reservoir 80 via line 101 into control valves 102. Each control valve 102 is a closed center, four-way valve connected to each pair of cylinders 31 and 32 on opposite sides of the front and rear tractive roller assemblies 10. A pressure line 103 extends from each control valve 102 and is provided with adjustable pressure-sensitive valves 104 and 105 with a line extending into the cylinder ends of the longer cylinders 32. The pressure switch or valve 104 senses the drop in pressure in the pressure line 103 to activate control valve 102 and, for example, will maintain the valve 102 in an open position until its associated cylinders 32 are extended and the pressure is increased in the pressure lines. For example, this would occur when the cylinders are extended to force the tractive roller assemblies into engagement with the ground and when the pressure increases beyond the pressure setting of the switches 104 to cause the switches to open and return the valves 102 to a closed position whereby to hold pressure in the line. Each valve 105 operates more in the manner of a shut-off valve, independently of the valve or switch 104, to sense an abnormally high pressure condition and return the valve 102 to a closed position. In this relation, it will be noted that the pressure line 101 extends or is connected to the center of each valve 102, and the end of the valve 102 opposite to pressure line 103 also has a pressure line 106 with a relief valve 107 which extends to the leading end of each double-acting cylinder. In addition, a hand or foot control, not shown, associated with each control valve controls the application of fluid under pressure to each pair of cylinders in traversing uneven or difficult terrain. Normally, in traversing flat or smooth terrain, the tractive roller assemblies 10 can be raised to the position as shown in dotted lines in FIGS. 1 and 7 so that fluid pressure is applied only to the track drive motors 84.
Again, each pressure sensitive valve 104 is preset to a predetermined pressure level so as to automatically compensate for variations in pressure. If the pressure should increase beyond a preset limit, for example, in driving the tractive roller assemblies 10 downwardly against the ground surface, pressure is relieved by an adjustable relief valve 118. The same is true if pressure is applied from the opposite side of the control valve to the leading end of the cylinders in which event pressure is relieved by the relief valves 118 independently of the pressure valves 104 or 105.
In certain situations, when it is desired to raise or lift the machine, the vehicle is suspended from the tractive roller assemblies by advancing the assemblies 10 to the lower dotted line position illustrated in FIG. 7. This can be accomplished by activating an accumulator 110 which receives excess fluid pressure from the pressure line 96 leading from pump 100 and dumps its stored fluid under pressure through a dump valve 112 and via pressure line 114 which communicates with branch lines 114' having check valves 115 therein in order to simultaneously advance each of the cylinders to their suspended positions while bypassing the pressure lines 103. Return lines 117 extend from the piston end of the cylinders, each provided with a relief valve 118 and direct the fluid back through normally open dump valves 120 of the throttling type into the reservoir 80. It should be noted that the dump valves 95 and 112 are normally closed but will open when called for to deliver the higher pressure fluid from the accumulators 94 and 110.
In operation, a hydraulic control circuit as described is manually controllable from the operator section to perform various functions. For example, in accord with the conventional practice, the track drive motors 84 can be independently operable through foot control panels in the operator section to control steering and rate of speed of the vehicle. In other words, turning in either direction can be controlled by regulating the relative speed of each track drive motor. In over-the-road use, normally the roller assemblies 10 are advanced to a raised position, such as, the uppermost position illustrated in dotted form in FIG. 2, by retracting the inboard cylinders 32 and extending the outboard cylinders 31. Conversely, the tractive roller assemblies can be pivoted to a position as illustrated in full both in FIGS. 2 and 7 in which the cylindrical beater elements will cooperate with the tracks in propelling the vehicle in either desired direction by extending the inboard cylinders 32 and retracting the outboard cylinders 31. Continued extension both of the inboard and outboard cylinders is effective to advance the cylindrical beater elements in a downward direction either to increase the pressure with the ground or if desired to raised the main body of the vehicle above the ground. As previously described, the pressure switches 104 will regulate the amount of pressure applied to the cylinders 31 and 32 within a predetermined setting or limit. However, when the vehicle is at rest this pressure may be increased by activating the accumulator 110 via dump valve 112 to bypass the pressure sensing valves 104 and 105 and deliver fluid directly to the cylinders via the branch lines 114'.
As further represented in FIG. 9, a gyro control circuit 124 is electrically connected via the solenoid control 125 for the valves 102 in order to automatically control the pivotal movement of the front and rear tractive roller assemblies depending upon the attitude of the vehicle in climbing or descending steep grades or hills. For instance, the gyro circuit 124 may be a Model No. VG24-08254 manufactured and sold by Humphrey, Inc. of San Diego, Calif. In traveling up a steep incline, the gyro will automatically respond to the inclination of the vehicle to regulate the relative amounts of pressure applied to each of the front and rear tractive roller assemblies. Thus generally as the vehicle is traveling uphill the gyro circuit will respond to increase the pressure at the rear tractive roller assembly while maintaining the pressure at the front tractive roller assembly. Conversely, as the vehicle starts downhill, the front tractive roller assembly is pivoted downwardly to increase the pressure with the ground surface while maintaining the pressure at the rear tractive roller assembly. This can be most efficiently done by permitting the gyro to operate either the back or front assembly depending upon whether the vehicle is traveling uphill or downhill. If traveling uphill, the gyro will operate the rear assembly and the pressure compensating switches will regulate the pressure of the front roller with respect to the ground surface; and the reverse is true in traveling downhill. Most desirably, the manual control will override the gyro circuit so that the operator may at any time assume control of the tractive roller assemblies whether or not the gyro circuit has been activated.
If it is desired to employ either the front or rear tractive roller assembly in digging or clearing operations, the vehicle is advanced into position and either of the drive motors 36 is operated to rotate the beater elements, for example, in clearing brush, digging or grading. As the gear housing is rotated, the fingers are progressively extended as they move into a ground-engaging position, then retracted through the housing so as to remove any debris or dirt from the fingers as they move away from the ground-engaging position. Most desirably, the fingers are displaced from one another as shown so that they will successively advance into engagement with the ground. The conical end sections further cooperate in digging or clearing operations but more importantly lend increased stability to the vehicle, for example, in traversing side hill inclines.
It will be appreciated that in certain applications it may be necessary only to employ a tractive roller assembly at one end of the vehicle, particularly if the roller assembly is to be utilized only in clearing or grading operations and not to aid in propulsion of the vehicle over uneven terrain. Moreover, the tractive roller assemblies as described can be efficiently utilized in combination with vehicles other than track-type vehicles, although for the reasons described can be most efficiently operated with a common hydraulic control circuit which is employed to operate the tracks of the vehicle. In addition, it will be evident that various angle or tilt sensing units can be employed in place of the gyro circuit, in which event the attitude of each roller assembly can be manually controlled to adjust the angle of each roller assembly in response to changes in slope or angle being traversed.
Accordingly, it is to be understood that the above and other modifications, changes and alterations may be made in the construction and arrangement of the preferred embodiment of the present invention without departing from the spirit and scope thereof as defined by the appended claims.
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An all-terrain vehicle includes a vehicle body with ground-engaging tracks and boom members pivotally mounted at each end of the vehicle which support generally cylindrical, cleated roller assemblies, the roller assemblies being characterized by having a plurality of fingers eccentrically mounted for extension and retraction with respect to the housing as the housing is rotated. Either roller assembly can be independently operated to perform digging and clearing operations as well as to permit lifting or lowering of the vehicle and at the same time cooperate in advancing the vehicle over uneven or hilly terrain.
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BACKGROUND OF THE INVENTION
The present invention relates to a device for regulating the length of thread absorbed by a flat or circular knitting machine.
The notion of absorbed length of thread (ALT) per mesh, which was introduced by the Centre de Recherche de la Bonneterie is now well known and used by knitwear manufacturers. It is an important parameter which is taken into account in the regulation of knitting machines. The constancy of the ALT in the course of the knitting enables articles to be obtained whose dimensions will themselves be constant. The ALT is a function essentially of the adjustment of the dropping cams and of the conditions of supply of the thread. Now, for a same thread, the supply conditions will themselves be a function of the coefficient of friction of the thread: for a given adjustment of the dropping cams and adjustment of the thread-tighteners, if the coefficient of friction of the thread varies in the course of the knitting, the ALT thereof will be modified. These modifications will result in irregularities as regard the dimensions of the knitted article and its possible rejection.
To overcome this drawback, the simplest solution has been to install positive supply devices for each thread in the machine. The speed of these positive supply devices is regulated so as to deliver to the machine the length of thread corresponding to the desired ALT. Thus, whatever the coefficient of friction of the thread, the machine receives the predetermined amount of thread uniformly. This solution is not however envisageable for all types of machines. In fact, the positive supply device having a continuous operation can only be suitable in the case where the thread is distributed permanently to the needles; it is mainly suitable for circular knitting machines. On the other hand, this solution is not adapted to machines where the thread is distributed discontinuously to the needles, particularly flat knitting machines.
Another solution for overcoming the irregularities of the ALT in the course of knitting is to modify the tension of the thread supplying the machine. In fact, the variations in coefficient of friction of the thread will also be manifested by variations in the tension exerted on the thread by the various members upstream of the machine. Devices are already known intended to correct the variations in tension of the thread. Swiss Pat. No. 12 160/74 of Sept. 6, 1974 describes a device comprising a double-cup tensioning means between which the thread passes, and electromagnetic means having an action on the cups and causing the pressure exerted by the cups on the thread to be varied, this action being itself controlled by the opening or closing of the switch, caused by the friction of the thread on a guide element forming part of the switch.
In French Pat. No. 1 544 469 of Nov. 14, 1967, the variation in tension of the thread results in the movement of a roller and the action of the latter on a diaphragm pneumatic device controlling the approach or separation of the two cups of the tensioner. In French Pat. No. 71 40 701, the variation of the tension of the thread results in the movement of a rod fast to a cam which itself acts on a spring connected to the cups of the tensioning means.
Although they respond theoretically to the problem set the above-described devices have not really been applied to flat machines, either on account of resonance phenomena when it is mechanical and interdependant means which are employed, or on account of their lack of reliability, or on account of their lack of sensitivity or on account of their all or nothing action.
In addition, if the ALT is very certainly dependant on the tension of the thread supplying the machine and hence the variation of the ALT is an inverse function of the variation of this tension, it is important to note that the tension is a parameter which can vary almost momentarily: a very localised irregularity of oiling on the thread can result in a sudden variation in the tension. However, the variation in ALT which will be manifested by a fault in the knitted article is not that arising from these momentary jerks in the tension. What is useful for the quality of the finished product and what must hence be regulated, is the variation in the ALT due to a gradual change in the coefficient of friction of the thread or to a sudden variation in the average friction. The coefficient of friction can in fact vary of course from one material to another and, for the same material, from one numbering or from one presentation to another and, for the same type of thread, from one batch, from one spool, or from one color to another.
There has been found, and this is what forms the subject of the invention, a device which responds to the exigencies of knitwear manufacturers for regulating the ALT of circular and flat knitting machines, and which, consequently, enables also correction of the non-instantaneous variation in tension on a thread. This device comprises a tensioning means of known operation, whether this is a double cup tensioner, a bar tensioner, whether it is a braked rotary tensioner, or whether it is a tensioner acting by gripping the thread. It also comprises a first means for varying the tension exerted by the tensioner on the thread, a feeler element over which the thread passes and which is moved when the tension of the thread varies and a second means for controlling the action of the first means as a function of the movement of the feeler element, characterised in that the first means comprises a drive member whose rotation results in the movement of the tension generating member of the tensioner, and in that the second means comprises two switches, one controlling the placing in rotation of the drive member in one direction and the other controlling the placing in rotation in the other direction. The direction of rotation of the drive member is determined so that the tension generating member of the tensioner is moved in the direction of an increase in the tension of the thread in the case where it is the switch corresponding to a value of the ALT higher than the average normal value which has been actuated and conversely.
On the other hand, the rotation of the drive member is interrupted when, under the effect of the increase or of the decrease in the tension exerted on the thread by the movement of the tension generating member of the tensioner, and hence taking into account the consequent variation of the ALT, the feeler element is moved until it is no longer beyond or opposite the switch and comes back into the zone situated between the two switches. It is hence possible to decompose the space that the feeler element can scan into three zones. In the central zone bounded by the two contact switches, the movement of the feeler element does not result in any effect on the drive member; this zone corresponds to an acceptable variation in the ALT and the tension of the thread. On each side of this central zone are situated two zones where the presence of the feeler element results in the rotation of the drive member, for one of the zones in one direction, for the other zone in the other direction.
It is understood that with the device of the invention it will be easy, by moving one with respect to the other, each of these three zones, to obtain an accurate adjustment of the range of variation of the ALT around the average normal value which is acceptable, in the same way as the adjustment of the average normal value, as a function of the type of material, of thread, of batch and of spool.
Advantageously, the drive member whose rotation results in the movement of the tension-generating member of the tensioner comprises a motor with two directions of rotation. It may however be constituted by a motor only rotating in one direction, coupled to a reversing system, for example a rack, enabling the direction of rotation transmitted to be reversed.
The tensioner according to the invention is anyone of known tensioners. It may be taken particularly from among barrage tensioners comprising one, two or several elements in contact with the thread and where the tension exerted on the thread is a function of the contact arc between the thread and the elements which compose the bars. Among tensioners acting by gripping the thread where the tension exerted on the thread is a function of the pressure exerted by the movable gripping member on the thread; among braked rotary tensioners where the tension exerted on the thread is a function of the force exerted by the braking member on the rotating element driven by the thread. As tensioner acting by gripping the thread, may be mentioned in particular the two cup tensioner between which passes the thread and where the tension exerted on the thread is a function of the pressure exerted by a pressure member such as a spring on the two cups.
Switches controlling the rotation of the drive member in one or other direction are conventional electrical switches or preferably magnetic type ILS switches (flexible blade switches).
In the device according to the invention, the variation in the ALT results in the movement of the feeler element over which the thread passes, this movement being able to trigger the closing or opening of the switch. The feeler element comprises a thread-guide, of known type, and a rigid rod situated so that, on the movement of the feeler element, said rod comes into contact with electrical switches or opposite magnetic switches. In the case of magnetic switches of the ILS type, the rod will be matched to a magnetic mass.
The movement of the feeler element due to the variation of the ALT is a result of a variation in the length of travel of the thread between three points of which the two extremes are fixed, and the third situated between the two first is movable. It is this third point which is materialised by the thread-guide of the feeler element and which is moved as a function of the variations in the ALT and the tension exerted on the thread. If the ALT increases and hence the tension decreases, the length of the path tends to increase; if the ALT decreases and hence the tension increases, the length of the course tends to diminish. The third point which is moved to follow the variation in the length of the travel of the thread may be moved from above downwards or from below upwards for the same length variation.
These two possibilities have given two embodiments. In the first embodiment, the feeler element comprises a mass whose constant weight communicates by means of the thread-guide to the thread a certain constant tension, it is on this mass that the rigid rod which actuate the two switches is fixed. In the second embodiment, the thread-guide of the feeler element is fixed to the end of a lever oscillating around a fixed axle, the other end of said lever acting as a rigid rod and actuating the two switches. Advantageously, the end of the lever serving as a rigid rod is equipped with a counterweight movable along said lever, so as to regulate by simple movement of said counterweight the tension exerted on the thread by means of the thread-guide. Advantageously, the supports of the switches are fast to the axle around which the lever pivots, so as to enable the movement of said switches with respect to the rigid rod and hence the adjustment of the three zones by simple rotation of said supports around said axle.
Advantageously, a detection system is placed in the path of the thread downstream of the device according to the invention and upstream of the knitting machine, the detection system having the purpose of detecting if the thread is moved or not and blocking the operation of the device for regulating the ALT in the case where the thread would not be moved.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood by means of the embodiments given below by way of indication, but which are in no way limiting, and which are illustrated by the accompanying drawings.
In the drawings:
FIG. 1 shows a device according to the invention in which the feeler element comprises a mass acting by gravity on the thread, the contact switches are conventional electrical switches and the tensioning means is a tensioner with two barrage elements.
FIG. 2 shows a device according to the invention in which the feeler element comprises an oscillating lever, the contact switches are ILS type magnetic switches and the tensioner is a double cup tensioner.
FIG. 3 is a partial and detailed view of the embodiment illustrated in FIG. 2.
FIGS. 4 to 8 are illustrations of diferent types of tensioners: in a two barrage tensioner (FIG. 4), a multiple barrage tensioner (FIG. 5), a so called tap tensioner (FIG. 6), a ball tensioner (FIG. 7), a rotray tensioner braked by mechanical friction (FIG. 8).
DESCRIPTION OF PREFERRED EMBODIMENTS
The thread 2 supplying the flat knitting machine of which only the needles 16 are shown is paid out from its spool 1 by alternate movements of the carriage of the machine, actuating the thread take-up by the needles 16.
In the embodiment illustrated by FIG. 1, the thread 2 passes over the fingers 17 and 18 of the tensioner 3, so as to form a barrage means before passing over the thread guide 5. The two fingers 17 and 18 are fixed to one of the flat surfaces of a cylindrical support 20, symetrically with respect to the axle 19 of said support. The rotation of the cylindrical support causes the contact arc of the thread with the two fingers of the barrage means to vary and therefore to vary the tension exerted on the thread. This rotation is controlled by the drive member which comprises the two way-rotating motor 4, and a wheel 21 in contact with the surface of revolution of the support 20 and driven by the motor 4.
Thus, the rotation of the motor 4 in one direction results in an increase in the contact arcs between the thread 2 and the barrage means fingers 17 and 18, increases consequently the tension exerted on the thread by the tensioner 3 and results in a reduction of the ALT. The reverse effect is produced by the rotation of the motor 4 in the other direction.
The feeler element 10 is constituted by a thread guide 6 connected to the mass 9 on which the finger 13 is fixed (FIG. 1). The feeler element can be moved vertically inside a chamber bounded, for example, by studs (not shown).
The switches 14 and 15 are located on each side of the finger 13, the movement of the finger 13 in the direction of the arrow S1 closing the switch 15, the movement of the finger 13 in the direction of the arrow S2 closing the switch 14. The closing of the switch 15 actuates the rotation of the motor 4 in the direction resulting in increase in the contact arcs between the thread 2 and the barrage fingers 17 and 18, that of the switch 14 actuates the rotation of t the motor 4 in the direction resulting in the decrease in the contact arcs.
When the knitting machine is in operation, the thread 2 passes through the tensioner, the thread guide and the feeler element before arriving at the needles; the thread possesses a certain tension which is determined to obtain a given ALT. This tension is a function particularly of the value of the contact arcs between the thread 2 and the barrage fingers 17 and 18, and of the mass of the feeler element, this mass having been selected taking into account the desired tension. In the course of operation and for a constant ALT, the feeler element 10 is in equilibrium between the fixed thread guides 5 and 7. In fact the length of the loop 5-6-7 formed by the thread is defined by the position of the feeler element 10 and the equilibrium of the forces exerted on the thread on each side of the feeler element and the constant force resulting from the action of the mass 9. When the coefficient of friction of the thread changes in the course of the operation of the machine, the equilibrium of the forces is broken. If the coefficient of friction increases and hence the ALT diminishes, all the forces exerted by friction on the thread upstream of the needles 16 will increase and will move from below upwards the feeler element 10 of which the constant mass counters said forces: the thread guide will pass from position 6 to 6', the finger 13 following the direction of the arrow S2 will close the switch 14 which actuates the rotation of the motor 4 in the direction of diminishing the contact arcs between thread 2 and the barrage fingers 17 and 18; the frictional force exerted by the tensioner 3 on the thread 2 will diminish: the feeler element will again be moved from 6' to 6 until the finger 13 recovers a position where the switch 14 is again open, said position corresponding to an acceptable value of the ALT. The procedure is, of course, reversed when the coefficient of friction of the thread diminishes in the course of operation of the machine and hence the ALT increases: the movement of the thread guide of the feeler element will be from 6 to 6", of the finger 13 in the direction of the arrow S1, the switch 15 will be closed which results in the rotation of the motor 4 in the direction of increasing the contact arcs between the thread 2 and the barrage fingers 17 and 18, the frictional force exerted by the tensioner 3 on the thread will increase and the feeler element will come back to its equilibrium position where the finger 13 leaves the switch 15 to find itself in the zone inermediate between the two switches 14 and 15.
In the second embodiment illustrated by FIGS. 2 and 3, the tensioner is a double cup tensioner. The thread 2 passes between the cups 11 and 12 of the tensioner 3. The upper cup 12 is fixed: the lower cup 11 can by moved in height and, applied more or less to the thread 2 which is moved between the two cups, can exert on said thread a greater or lesser pressure, by means of the drive member which comprises the motor 4 with two directions of rotation, an element 35, a threaded rod 34 and a spring 33: the rotation communicated by the motor 4 is transmitted to the element 35, then transformed into a linear movement of this element 35 along the threaded rod 34, said element compressing or decompressing the spring 33 which exerts a pressure on the lower cup 11. In the present embodiment, the element 35 is a wing nut rotated by means of two arms of another wing nut 36 fast to the axle of the motor 4. It could also have been a gear wheel rotated by another gear wheel fast to the axle of the motor 4. Thus, the rotation of the motor 4 in one direction results in the compression of the spring 33, increases the pressure of the cup 11 on the cup 12, increases the tension exerted on the thread by the tensioner 3 and results in a reduction in the ALT. The reverse effect is produced by rotation of the motor 4 in the other direction.
Feeler element 10 is constituted by a lever 28 oscillating around a horizontal axle 23, one end of said lever being terminated by the thread guide 6, while the other comprises a magnetic portion 24. The principle of equilibrium of the forces is identical with that disclosed in the first embodiment, with the exception that the mass corresponding to the magnet 24 exerts, through the lever 28 oscillating around the horizontal axle 23, a force from below upwards on the thread 2 passing into the thread guide and not from above downwards as in the preceding example. The magnet 24 may be equipped with a counterweight 29 sliding along the threaded rod 30: the adjustment of the force that is desired to apply to the thread 2 is obtained by selecting the given counterweight 29 and, for a same counterweight, by moving it along the threaded rod 30. The magnet 24 is located in a zone limited by the two magnetic switches of type ILS, the one controlling the placing in rotation of the motor 4 in one direction and the other the placing in rotation of the motor 4 in the other direction. The ILS switches are positioned so that, when the thread guide 6 of the feeler element 10 is moved towards 6' under the effect of a reduction of the ALT due to an increase in the coefficient of friction of the thread 2, the arm of the lever 28 supporting the magnet 24 is moved in the direction of the arrow S2, the magnet 24 closes the magnetic switch 26 which controls the rotation of the motor 4 in the direction which results in the decompression of the spring 19 and the separation of the cups 11 and 12: the ALT increases and the tension of the thread decreases until the feeler element 10 recovering its equilibrium position, the magnet itself also recovers its intermediate position, the switch 26 being open and the motor 4 stopped; in the same way, conversely, with the element 6 towards 6" and with the action of the switch 25, in the case of a reduction in the tension of the thread 2. This second embodiment enables the predetermined tension on the thread to be regulated to values below those of the first modification. The adjustment of the acceptable range for the variations of the ALT is done by means of different means enabling the positioning of the ILS 25 and 26 on each side of the end of the lever 28 supporting the magnet 24, once the position of the latter will be determined. The positioning means of the ILS are, in the embodiment illustrated by FIG. 3, a first support 32 possessing a handle 31 and movable in rotation around the axle 23, on which the ILS 25 is fixed whilst the ILS 26 is fixed to a second support 27 movable in rotation around the axle 23, the second support 27 being fastenable by suitable locking to the first support 32. Thus, the separation between the switches 25 and 26 fixing the zone corresponding to an acceptable ALT is obtained by means of the movement of the second support 27 with respect to the first support 32, and the adjustment of device is obtained by movement of the first support 32 so that the two switches 25 and 26 are equidistant from the magnet 24 in the equilibrium position for the average value of the desired ALT.
The stability of the oscillating lever 10 is ensured by its V shape, such that its central gravity occurs below the axis of rotation 23, and on the other hand by an inertial mass fast to the axle 23.
The thread guide 7 situated immediately upstream of the knitting machine forms part of a detection system 34 which detects if the thread is moved or not and only permits the regulation device of the ALT in the case of a movement of the thread.
The system is particularly useful when the regulation device of the ALT is adapted to non-circular knitting machines where the supply of the thread to the machine follows an alternating movement; in this case, the information of arrest or movement of the thread to the regulating device of the ALT is indispensable so as not to experience, at the end of the needle beds any inadvertent and troublesome actions of the regulation device concerned, for example, of the normal relaxation of the thread on stopping between a left right, right left or right left, left right run. This detection system is also useful on stoppages of the knitting machine for any reason; in fact, in this case, the thread 2 will have a tendancy to relax and the thread guide 6 to come into position 6", which, if the detection system does not block the regulation device of the ALT, will result in the closing of the switch 25 and by rotation of the motor 4, the compression of the spring 19, without increase in tension on the thread being manifestable by a reduction in the ALT and a return of the feeler element 10 towards its equilibrium; on restarting the machine, the tensioner exerting an excessive tension, the thread would break.
The tensioner employed in the first embodiment illustrated by FIG. 1 is a tensioning means comprising as tension-generating member two barrage elements. Like all barrage tensioning means, it acts by friction of the thread on the barrage elements; the adjustment of the tension is effected by causing the contact arc between the thread and said elements to vary. FIGS. 4 to 6 illustrate non-limiting examples of tensioners operating according to the same principle. The tension generating member of the tensioner shown diagrammatically in FIG. 4 also comprises two barrage elements, one 40 is a fixed cylindrical frictional body and the other 41 is barrage finger mounted on a cylindrical support 42, rotating around its axle 43; the movement of this tension generating member is a rotary movement around the axle 43 caused by the rotation of the wheel 44 which is in contact with the surface of revolution of the cylinder 42, and which is driven by the motor 4 (not shown). Tension generating member of the tensioner shown diagrammatically on FIG. 5 consists of a thread guide unit 45b into which the thread passes, which is intercalated with another thread guide unit 45a. The latter unit is fixed, whereas the unit 45b is movable vertically under the action of a double acting cam 46, self actuated in rotation by a motor member 4 (not shown). The tension generating member of the tensioner called tap type shown diagrammatically in FIG. 6 is a body 47, pierced from side to side and through which the thread 2 passes, movable in rotation, and its movement is driven by a wheel 48 in contact with the surface of revolution of body 47, itself rotated by the motor member 4 (not shown).
The tensioner employed in the second embodiment illustrated by FIGS. 2 and 3 is a double cup tensioner. Like the other example of a tensioner acting by gripping of the thread, FIG. 7 shows a ball tensioner, where the tension generating member comprises a ball 49 or possibly a pressure shoe; The thread 2 enters a tube 50 through an orifice 51 formed in the side wall of said tube and emerges there-from through an orifice 52 fashioned in the flat wall. In contact with this wall, the thread 2 is gripped by the ball 49. The variation in tension is caused by more or less stronger or weaker application of the ball 49 to the thread 2, under the effect of a spring 53, which is more or less compressed by the action of a cam 54, actuated in rotation by a drive member 4 (not shown).
It is possible to use braked rotary tensioners. In these tensioners, the thread passes over a wheel 61 free in rotation around its axis, this wheel is rotated by the friction of the thread on its surface of revolution. The tension generating member of this type of tensioner is a member for braking the wheel driven by the thread. The braking can be caused by friction between the wheel 61 and the braking member, whether this friction is mechanical, as in the example illustrated in FIG. 8, or magnetic (Eddy currents, hysteresis); it may also result from a resisting counter-torque created, for example, by a motor. The tension generating member shown in FIG. 8 comprises a disk 56 which is urged on to a flat surface of the wheel 61, a spring 57 surrounding a threaded rod 60 mounted on the axle of the disk 56 and a gear 58 moving on its rotation on the threaded rod 60. The motor member 4 through a gear wheel 59, causes the gear wheel 59 to rotate, which results in the rotation of the wheel 58 which through this fact is moved along the thread rod 60. The rotation of the drive member 4 in one direction results in the movement of the threaded rod 60 towards compression of the spring 57, and hence a greater application of the brake-disk to the wheel 61: the rotation of the drive member 4 in the other direction reduces the braking force applied to the wheel 61.
As has just been described, the device according to the invention regulates the length of the thread absorbed by the knitting machine. Its particular field of application is constituted by machines where the positive supply of the thread by the supplier is either impossible, or too burdensome; this is the case particularly with circular knitting machines with striping units, Jacquard flat or circular knitting machines; flat or Cotton knitting machines, socks, hose or pantyhose knitting machines, sock and stocking looms, as well as all circular machines of small diameter. As has also been stated, this device is also useful to correct non-momentary variations in the tension of the thread, which permits its employment on any other equipment than knitting machines where it is important to regulate this tension around an average value, particularly all winding and spooling equipment.
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A device for regulating the length of thread absrobed by a knitting machine and/or for correcting the variations in tension of a thread supplying a textile machine, is disclosed. The device comprises a tensioning means of any type, a drive member whose rotation results in the movement of the tension-generating member of the tensioning means, a feeler element over which the thread passes and which is moved when the length of thread absorbed and/or the tension of the thread varies and two switches, one controlling the placing in rotation of the drive member in one direction and the other the placing in rotation in the other direction. The direction of rotation of the drive member is selected so that the corelative action of the feeler corrects the variation in the length of thread absorbed and/or of the tension which is the cause of triggering this rotation.
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BACKGROUND
1. Field of Invention
This invention relates to the method for the manufacture of structural foam articles having a predetermined skin thickness and a foam interior from the same basic resin compound.
2. Description of Prior Art
The present method of manufacturing structural foamed articles consist chiefly of two type of methods and apparatus. In one method as set out in the Angell U.S. Pat. No. 3,268,636 a method is described wherein a blowing agent is mixed with a plastic resin and then extruded into an accumulator until the proper amount is collected and kept at a temperature and pressure to prevent foaming. A valve is then transferred which now connects the accumulator to a mold wherein the plastic resin is forced into the mold where it will foam and expand forming a cell-like structure. The external skin of the article is chilled faster than the inside and therefore will form a continuous surface without holes or blemishes. However, with this method it is very difficult to control the skin thickness since the whole method relies on the mixing of the foaming agent, the foaming action of the plastic mixture, the temperature and pressure of the accumulator and mold structure, and its temperature gradient during cooling.
In the other method of injection molding foam products described in the Garner U.S. Pat. No. 3,599,290, two extruders are used wherein each contains a different type plastic resin. Here one extruder will inject a plastic of one type material into the mold, then a valve is transferred and a second type plastic, which will foam, is extruded into the mold to form the internal structure of the article. The mold halves are then opened a controlled amount and the foamed internal structure will fully develop. Here the skin thickness can be controlled because a fixed amount of that particular plastic was available within the mold from the first extruder and the foam will continue to expand giving the desired cell structure as the mold is allowed to open. Both quantities of each type plastic extruded is controlled by the timing of the extruders during the injection process so that the skin thickness and ultimate density of the article is controlled on a repeatable basis. Although not a problem but rather an expense in this second method is the use of two extruders for the skin and core of the article. My invention overcomes this drawback by requiring only one extruder.
In the former example the skin thickness was uncontrolled because when the accumulator was connected to the mold, the plastic flow was virtually uncontrolled and therefore the skin thickness variation and the ultimate core cell structure is a function of many variables which can change from shot to shot. Here my invention establishes a fixed quantity of solid material which will fix the minimum wall thickness as the foamed plastic is injected into the mold.
SUMMARY
This invention utilizes a single plasticating extruder wherein a foaming agent is added by a nitrogen pump. The outlet of the extruder is connected to an auxiliary mixer and via a check valve to an injection chamber and from there to the mold. By operating the extruder with the nitrogen pump turned on, a steady stream of foamed plasticized material can be extruded into the injection chamber. After a specific volume is reached a switch will turn off the nitrogen pump and the unit will now extrude a non-cellular or homogeneous plasticized material until a second switch is tripped which will stop the extruder. The shut-off valve in the nozzle will now open and the extruded plasticized material in the injection chamber will be shot into the mold. The first portion to enter the mold cavity will be the non-cellular material and form the outer skin of the article to be produced, then the second portion of the accumulated material will enter the mold forming the cell-like internal structure of the article. The shut-off valve will now seal the nozzle and the cycle will be repeated.
The cycle of the apparatus can be operated such that a non-cellular material is at both the beginning and end of the shot. This will produce a non-cellular plastic sprue and allow a smooth finish at the break point of the sprue and article leaving a non-cellular material in the nozzle and passages available for the next article to be produced.
A static mixer following the extruder can be added as well as a liquid coloring pump so that the color of the plastic can be changed without completely changing the material in the hopper. This object will make color changes to the finished product more convenient and less costly.
Depending on the size of the part to be manufactured, additional sprues or runners can be added so that the material can be injected into the mold cavity simultaneously through more than one opening. Also the density of the part produced is a function of the volume or size of the pipes and bores in the system and an object of this invention is to consider these volumes as related to other elements in the system.
A further object is to allow the extruder to be shut off during periods of inactivity thus conserving power and energy as compared to most extruders used in this art which must be operated continuously. During the shot cycle of such continuously operated extruders, the material extruded is dumped overboard and discarded, or accumulated, reground, and then mixed in with virgin plastic. This procedure of dumping material is not necessary in my invention.
IN THE DRAWINGS
FIG. 1 is an overall partial section of the extruder, miser, piping, injection chamber and mold sections;
FIG. 2 is a view showing non-cellular plastic resin displacing injection chamber piston;
FIG. 3 is a view showing foamed plastic resin displacing injection chamber piston;
FIG. 4 is a view showing additional non-cellular plastic resin displacing injection chamber piston;
FIG. 5 is a view showing non-cellular material injected into mold from injection chamber;
FIG. 6 is a view showing the foamed material injected into mold from injection chamber;
FIG. 7 is a view showing first extruded non-cellular plastic resin injected into mold; and
FIG. 8 is a view showing the nozzle shut-off and completion of the cycle.
DESCRIPTION
The overall apparatus of my invention can be viewed in FIG. 1 which shows a hopper 12 and an extruder 10 driven by a motor means 15 with the outlet of the extruder 10 connected by pipe 14 to a static mixer 16. Near the outlet of the extruder 10 is a pump 18 having a fluid blowing agent source such as nitrogen connected to it. Some other type of blowing agents such as another gas or a liquid could be used in lieu of the nitrogen. Also connected near the outlet of the extruder 10 is a pump 20 having a source of fluid color additive available as well. The check valves 19 and 21 are associated with the blowing agent pump 18 and color additive pump 20 respectively. The flites on the extruder 10 are modified and fittings 11 and 22 are adapted to accept the inputs from the blowing agent and color additive pumps so these fluids enter the center of the melt stream. A plurality of fittings may be radially inserted for both the blowing agent and color additive to better distribute the fluids into the melt stream. The blowing agent source may also be in a plurality of input locations in front of and behind the location shown in FIG. 1 depending on the type of plastic and the size of the part to be produced. These locations would be in the front half of the extruder since a more rearward location could cause leakage of the blowing agent, if a gas, out of the hopper. Connected to the end of the extruder screw 9 is a torpedo-like structure having a frustoconical tip 6 and cylindrical section 7 having short pins or studs 8 extending radially around the circumference of the cylinder section 7 having a very close clearance to the inside diameter 5 of the barrel of the extruder. This torpedo-like element and its studs are a part of the extruder screw 9 and rotate with the screw causing a vigorous mixing of the melt as it exits the screw area or zone. This is in effect a dynamic mixer and is well known in the art.
The auxiliary optional mixer 16 contains a static element 17 which further mixes the plasticized resin with either the fluid blowing agent or the color additive or with them both.
The outlet of the mixer 16 is affixed to manifold 24 which contains a ball 25 and pin 26 at the inlet to form check valve 27, as disclosed in U.S. Pat. No. 3,806,291, into manifold bore 28. An injection cylinder 30 is shown housed in conjunction with the manifold 24 for convenience and could be a separate element connected by piping or tubing to the manifold. A bore 31 forms the inside diameter of the injection cylinder 30 having a conic surface 32 communicating from this bore to diameter 34 and thence to manifold bore 28. Closely fitting inside injection cylinder bore 31 is piston 35. The piston 35 is connected with piston rod 38 to plastic injection hydraulic cylinder 39. The volume bounded by conic surface 32, bore 31 and piston 35 form injection chamber 47.
Mold halves 45 and 46 are shown in FIG. 1 in a closed position held in place by the moving plate 50 and stationary plate 52 respectively of a typical clamp section of an injection molding machine.
The mold cavity 54 is connected to the sprue 55 to sprue bushing 57 through bore 58 and to nozzle 59 through nozzle bore 60. The sprue bushing 57 is affixedly held to the mold half 46 by any convenient means and the nozzle 59 is likewise affixedly held to manifold 24. Nozzle shut-off valve 63 is a hydraulically operated cylinder 65 with rod end 64 closely fitted into nozzle bore 60. Communicating with manifold bore 28 is cross bore 61 in nozzle 59 which intersects with nozzle bore 60 so that a continuous path from the plastic injection chamber 47 is made with the cavity 54 of the mold. A seal 62 in the nozzle 59 prevents leakage of plasticized material especially during the shot cycle.
Four limit switches 66, 68, 70 and 72 are located at the piston rod end of plastic injection chamber 47 and are affixedly held to the injection cylinder body 33 by rods 74 and 75. These switches are adjustable so that the correct amount of solid and foamed material can be injected for a given shot. These switches are connected to other electrical circuit elements such as relays or contactors so that proper signals and voltages can be delivered to operate properly in the correct timing sequence in the system. These switches are shown activated by the piston 35 but could be actuated by any convenient means signaling the various positions of the piston in the body of the injection chamber. For example a linear transducer could develop an electrical voltage proportional to distance and hence to volume which could be used in the same manner as the switches just shown.
The injection chamber hydraulic cylinder 39 is piped into the hydraulic circuitry and branches into three lines. One line is connected to a pilot operated check valve 79 and then to a pressure relief valve 80 which dumps to tank. The other two branches go to directional valve 78 and pilot operated check valve 76.
The hydraulic pump 41 is connected to a pressure relief valve 42 to tank and through a check valve 83 to a variable orifice 77 which connects to directional valve 78. A directional control valve 85 is connected to relief valve 42 and to tank to relieve pump 41 pressure after accumulator is charged. Another branch from pump 41 is connected to directional valve 43 through check valve 82 to pilot operated check valve 76. In parallel connections between the check valves 82 and 76 are a pressure switch 44 and a hydraulic accumulator 40. The pressure switch 44 may be connected to other electrical circuit elements for control purposes. The accumulator although appearing as a single element in the hydraulic system could have a plurality of hydraulic accumulators connected in parellel.
The sizes of the bores in the manifold 24 and injection chamber 47 as well as the size of the piping and bores from the nitrogen fitting 11 in the extruder to the mixer 16 and manifold 24 will be commensurate with the size of the foamed part to be produced and the ultimate density of the part. The part size itself is of course determined by the mold cavity 54 and a given shot size of the injection chamber 47, determined by either the full injection chamber volume or that set by the switches (66, 68, 70 and 72) associated with the injection chamber to control the function of the extruder 10 and nitrogen pump 20, will determine the final density of the part to be produced when considered in conjunction with the pipes and bores sizes between the various element in the system.
These bores and pipes or passages which connect from the fittings in the extruder to the injection chamber and from the injection chamber to the mold could represent a significant amount of the total volume of the injection chamber or in contrast a small portion of it. By way of example, if the total pipe volume as described is only 5% of the injection chamber volume, and assuming the plastic when unfoamed has a density of 1.00 and when fully foamed would have a density of 0.50, then the final minimum part density would equal 0.525 if maximum injection chamber volume is used. Obviously by injecting more non-cellular material the part density can be increased up to 1.00 which would be for a full non-cellular part and no foam. If the total pipe volume is 20% of the injection chamber size, with the same assumption as above, then the final minimum part density would equal 0.60 if maximum injector chamber volume is used. Still further if the pipe volume is 20% and only half of the injection chamber volume as controlled by the switches is used, the density would only go up to 0.70 since the pipe volume is now equivalent to 40% of the available injection chamber volume. The following table will show the pipe and bore volumes in terms of percentage of the injection chamber volume versus the part density using 1.00 as the non-cellular part density and using full volume of the injection chamber as the base and assuming only non-cellular material in the pipes and bores. The general range of thermoplastic densities are from 0.91 to 1.50 and the actual density desired for any given thermoplastic can be calculated from the table by multiplying the actual density of the thermoplastic by the density shown since this chart is set-up based on a thermoplastic density of 1.00.
______________________________________PIPE VOLUME PART DENSITY______________________________________ 5% .52510% .5515% .57520% .6025% .62530% .6540% .7050% .7560% .8070% .8580% .9090% .95100% 1.00______________________________________
Again it becomes very obvious that the total volume of the pipes and bores between the elements must be small in order to properly control the density of the part and the practical range for the volume of bores and pipe would be from nil, since it is impossible to have zero, to about 40%. The preferred and best range of pipe and bore volume would be from 5% to 25%. Here again, the number of nozzles, and size of the part will determine if the volume in the nozzles, pipes and bores become prohibitive from an economic and practical point which would require then that the injection chamber be changed to allow a reduced density of the part. Although only one nozzle is shown it is understood that a plurality of nozzles could be used.
MODE OF OPERATION
After an appropriate warm-up time so that heater bands associated with the extruder 10 and injection cylinder 30 would be up to temperature and other circuit elements have stabilized, the unit and system would be ready to operate. Hydraulic pump 41 would be turned on and directional valve 43 energized to port fluid into the accumulator 40. When this accumulator is fully charged, pressure switch 44 will de-activate directional valve 43 and the pressure will be trapped. Simultaneously directional valve 85 is energized venting pressure relief valve 42 and fluid would now be dumped at a lower pressure over relief valve 42 to tank. Pilot operated check valve 79 would now be opened and the relief valve 80 would be set to a variable pressure compatible with the polymer being plasticized to provide back pressure to injection cylinder piston 35. Extruder 10 would be turned on and would start to extrude plasticized resin into pipe 14 and through optional mixer 16 opening the check valve 27 at the end of the mixer and allowing the non-cellular resin to flow through manifold bore 28, bore 34 and into injection chamber 47 pushing back piston 35 allowing the non-cellular material to flow into the chamber bore 31 as shown in FIG. 2. When the correct amount of non-cellular material 23 is accumulated in the injection chamber 47 both limit switches 66 and 68 will be activated which will turn on pump 18; that will begin pumping a metered amount of blowing agent, in this case nitrogen gas, through check valve 19 and into the end of the extruder 10 where it will be forced into the melt stream, mixed and carried up stream through pipe 14 into the auxiliary mixer 16 where a static element 17 inside further mixes the resin and blowing agent together. The mixture of resin and blowing agent shown in FIG. 3 now continue to force the piston 35 back, filling the injection chamber 47 and at the same time the mixture 36 partially expands in the chamber with the amount of mixture 36 expansion controlled by the setting of relief valve 80, until the correct amount for the part to be molded is accumulated. At which time limit switch 70 is activated which now shuts off pump 18 and stops the metering of the blowing agent. Check valve 19 will prevent plasticized resin from coming into the pump 18 while the extruder continues to operate.
The extruder 10 continues extruding non-cellular material into the injection chamber 47 until limit switch 72 is activated which signals that a sufficient amount of non-cellular material 49 has been accumulated as seen in FIG. 4 and this also signals to shut off the extruder so that no further resin will be extruded or injected.
Referring now to FIG. 1, the pilot operated check valve 79 will now be closed so that no fluid can flow over relief valve 80 and directional control valve 78 will be energized. With pump 41 still operating, fluid will flow through variable orifice 77 into the injection hydraulic cylinder 39 causing it to ease the piston 35 forward and the melt will close check valve 27 which will prevent any flow of resin back to the extruder. The nozzle shut-off valve 63 will open and allow the free flow of resin from the injection chamber 47 through diameter 34 intersecting with manifold bore 28 in line with cross bore 61 in nozzle 59 connecting to nozzle bore 60 through sprue bushing bore 58 into mold cavity 54 through sprue 55 in mold half 46, best shown in FIG. 5. The rod 64 of cylinder 65 will stop clear of bore 61 but in front of the seal 62 in nozzle to help prevent leakage of resin. Now with the piston 35 moving forward at a controlled velocity because of variable orifice 77, plasticized non-cellular resin 49 will now be forced into the mold cavity 54 formed by mold halves 45 and 46. A short time delay can occur to allow the outer skin of the plasticized resin 49 to firm up, then pilot operated check valve 76 will be energized and the stored fluid in the hydraulic cylinder 39 will cause piston 35 to shoot the foamed mixture 36 into the mold as shown in FIG. 6 causing it to flow into the center of the previous non-cellular melt pushing it into the far reaches of the mold cavity without disrupting the firmed up outer skin and causing the part molded now to have a solid laminar outer surface structure with a finite thickness and a foamed or cellular inner structure. If the process were stopped at this time, the part, after it comes out of the mold and was degated or had the sprue removed, would have a cellular structure at the sprue point that would be difficult to cover or would require some secondary manufacturing operation. To prevent this, the non-cellular material 23 which was extruded first into the injection chamber 47 will now be forced into the mold as shown in FIG. 7 which will fill the bores and passages with a non-cellular resin material which will cause the gate or sprue to be non-cellular. When this operation is complete, limit switch 66 will signal the completion of the shot and nozzle shut-off valve 63 will operate to shut off nozzle as shown in FIG. 8 and complete the cycle. While the molded part is cooling, the extruder 10 is now turned on and the plasticizing cycle will start again. Also the accumulator 40 will be recharged with hydraulic fluid by operating the directional control valve 43 and that portion of the cycle will start again. It is obvious that the various limit switches will be connected to other electrical circuit element so that the proper sequencing and time delays will be met in compliance with the part to be produced.
Pump 20 is shown in FIG. 1 connected to a color additive source which will allow coloring to be added to the melt. For example the whole part could be one color, or the skin of the part could be one color and the core of the part could be another color. This would operate in conjunction with check valve 21 which would open to allow the flow of color additive from pump 20 into the end of the extruder 10 and, when the pump is shut off, would prevent plasticized melt from flowing back up into the pump itself.
In summary, a single action extruder capable of plasticizing resin is piped to an injection chamber. Near the end of the extruder is connected a foaming agent source to input the foaming agent into the center of the melt stream in front of a mixer which will thoroughly distribute the foaming agent into the melt. By controlling the sequencing of the extruder and the foaming agent pump, the foamed resin is sandwiched in the injection chamber with non-cellular resin on each side. A unique fact is that the foamed resin is allowed to expand in the injection chamber prior to it being shot into the mold which reduces the need for holding the melt at a much higher pressure, as practiced in the art, prior to it being shot into the mold. Also by only operating the extruder when necessary and adding a foaming agent at the appropriate time in the cycle, the non-cellular and foamed plasticized resin can be extruder from a single extruder sequencially into the injection chamber and then shot into the mold.
It is apparent that changes may be made to the process and structure described without departing from the scope of the invention as sought to be defined in the following claims.
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A method for the manufacture by foam molding of plastic products by first injecting into a mold non-cellular plastic resin and then injecting a foamed plastic resin of the same basic composition as the non-cellular plastic resin. The process and apparatus consisting of a single extruder and single injection chamber wherein the non-cellular and foamed plastic resin are extruded from the same extruder and stored in an accumulator until shot into the mold by a hydraulic cylinder. Controls are provided for the correct amount of each type of resin to be extruded and stored and the process can be adapted so that the sprue portion of the final product will be solid resin. By a simple addition, coloring of the resin may be accomplished so that the basic resin, method or apparatus will not require changes.
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RELATED APPLICATIONS
[0001] This is a continuation of, and claims priority to U.S. application Ser. No. 13/567,901, filed Aug. 6, 2012 and entitled “Methods for Performing Biometric Recognition of a Human Eye and Corroboration of the Same”, which in turn is a continuation of, and claims the benefits of priority to:
[0002] U.S. application Ser. No. 12/887,106 filed Sep. 21, 2010 and entitled “Methods for Performing Biometric Recognition of a Human Eye and Corroboration of the Same”, which in turn is a continuation-in-part of, and claims priority to:
[0003] U.S. application Ser. No. 11/559,381 filed Nov. 13, 2006, and entitled “Apparatus and Methods for Detecting The Presence of a Human Eye”, issued as U.S. Pat. No. 7,801,335 on Sep. 21, 2010, which in turn claims priority to:
[0004] U.S. provisional patent application No. 60/597,130 filed on Nov. 11, 2005, and U.S. provisional patent No. 60/597,152 filed on Nov. 14, 2005, and U.S. provisional patent No. 60/597,231, filed on Nov. 17, 2005, and U.S. provisional patent No. 60/597,289, filed on Nov. 21, 2005 and U.S. provisional patent No. 60/597,336 filed on Nov. 25, 2005. Each of these is incorporated herein by reference in their entirety.
BACKGROUND OF THE DISCLOSURE
[0005] 1. Field of the Disclosure
[0006] This disclosure relates generally to systems in which imagery is acquired primarily to determine or verify the identity of a person using a biometric recognition system, and more specifically to systems in which there is a need to detect the presence of a live, human eye in the imagery. The biometric used for recognition may be the iris, for example.
[0007] 2. Description of Related Art
[0008] Like a fingerprint, an iris can be used to uniquely identify a person. A number of systems have been implemented for this purpose. For one example, U.S. Pat. No. 4,641,349, titled “Iris Recognition System,” issued to Flom et al. on Feb. 3, 1987, and U.S. Pat. No. 5,291,560, titled “Biometric Personal Identification Based on Iris Analysis,” issued to Daugman on Mar. 1, 1994, discloses a system for identifying a person based upon unique characteristics of the iris. A camera captures an image of the iris, the iris is segmented, and then the iris portion is normalized to compensate for pupil dilation. The normalized iris features are then compared with previously stored image information to determine whether the iris matches.
[0009] For another example, U.S. Pat. No. 5,572,596, titled “Automated, Non-Invasive Iris Recognition System and Method,” issued to Wildes et al. on Nov. 5, 1996, discloses an alternate method of performing iris recognition using normalized correlation as a match measure. Further advantages and methods are set forth in detail in this patent.
[0010] For another example, U.S. Pat. No. 6,247,813, titled “Iris Identification System and Method of Identifying a Person through Iris Recognition,” issued to Kim et al. on Jun. 19, 2001, discloses another system used for iris recognition, which implements a unique identification methods. The system divides a captured image of an iris into segments and applies a frequency transformation. Further details of this method are set forth in the patent.
[0011] For yet another example, U.S. Pat. No. 6,714,665, titled “Fully Automated Iris Recognition Systems Utilizing Wide and Narrow Fields of View,” issued to Hanna et al. on Mar. 30, 2004, discloses a system designed to automatically capture and identify a person's iris. This system uses a camera with a wide field of view to identify a person and a candidate iris. Once identified, a second camera with a narrow field of view is focused on the iris and an image captured for iris recognition. Further details of this method are set forth in the patent.
[0012] One problem faced by iris recognition systems involves the possibility of spoofing. Specifically, a life-sized, high-resolution photograph of a person may be presented to an iris recognition system. The iris recognition systems may capture an image of this photograph and generate a positive identification. This type of spoofing presents an obvious security concerns for the implementation of an iris recognition system. One method of addressing this problem has been to shine a light onto the eye, then increase or decrease the intensity of the light. A live, human eye will respond by dilating the pupil. This dilation is used to determine whether the iris presented for recognition is a live, human eye or merely a photograph-since the size of a pupil on a photograph obviously will not change in response to changes in the intensity of light. One disadvantage of this type of system involves the time required to obtain and process data as well as the irritation a person may feel in response to having a light of varying intensity shone into their eye.
[0013] U.S. Pat. No. 6,760,467, titled “Falsification Discrimination Method for Iris Recognition System,” issued to Min et al. on Jul. 6, 2004, attempts to address this problem. This system positions a pair of LED's on opposite sides of a camera. These LED's are individually lighted and images captured through a camera. These images are analyzed to determine whether light from the LED's was reflected back in a manner consistent with a human eye. Because a flat photograph will not reflect light back in the same manner, this system aims to deter this type of spoofing. One disadvantage of this system, involves the simplicity of the approach and the placement of the LED's. With two LED's positioned at a fixed, known location, the method can be defeated by appropriate placement of two small illuminators in an iris image. Also, while this system may operate more quickly than systems that dilate a pupil, it still requires time to capture at least two separate images: one when each of the two LED's are individually lit. Further, a third image needs to be captured if the system requires both LED's to be illuminated to capture imagery that is sufficiently illuminated for recognition.
[0014] The above identified patents are each incorporated herein by reference in their entirety as well as each of the patents and publications identified below.
[0015] As mentioned above, it is well known that imagery of the iris can be reliably matched to previously recorded iris imagery in order to perform reliable verification or recognition. For example, see Daugman J (2003) “The importance of being random: Statistical principles of iris recognition.” Pattern Recognition , vol. 36, no. 2, pp 279-291. However since the iris patterns are not easily recognizable to a human, it is impossible to demonstrate to a user who has been rejected from any iris recognition system the reason for the rejection. On the other hand, if a face image of the person whose iris has been used for recognition is acquired, it is easy to demonstrate the reason for rejection since face imagery can be easily interpreted by humans. Therefore, especially in unattended systems, there is a need for a highly secure method of associating an acquired face image to an acquired iris image, preferably (although not necessarily) with just one sensor in order to reduce cost and size of the solution.
SUMMARY
[0016] This summary is provided solely to introduce a more detailed description of the invention as shown in the drawings and explained below.
[0017] Apparatus and methods for detecting a human iris use a computer screen on which an image is presented. The image is reflected off of a person's eye. The reflection is analyzed to determine whether changes to the reflected image are consistent with a human eye.
[0018] According to one aspect of the invention, a human eye is detected by presenting a first image on a computer screen that is oriented to face a user. At least one camera (and in some preferred embodiments at least two cameras) is positioned near the computer screen and oriented to face the user so that light emitted by the computer screen as the first image is reflected by the user and captured by the camera as a second image. The camera may be attached as part of the computer screen or separately mounted. A computer is operably coupled with the computer screen and the camera and the computer detects a human eye when at least a portion of the second image includes a representation of the first image on the computer screen reflected by a curved surface consistent with a human eye. The computer may be operated locally or operated remotely and connected through a network.
[0019] According to further aspects of the invention, the human eye is detected when the representation of the first image included in the second image is approximately equal to a human-eye magnification level, which is determined by dividing 3 to 6 millimeters by a distance from the computer screen to the user. For an implementation where the user is at least 100 millimeters from the computer screen, the representation of the first image is at least ten times smaller than the first image. For an implementation where the user is approximately 75 to 500 millimeters from the computer screen and the camera, the representation of the first image is approximately 12.5 to 166.7 times smaller than the first image. The determination can further require that the magnification at the center of the representation is smaller than a magnification in areas surrounding the center of the representation. Likewise, the determination can detect a human eye when the second image includes the representation of the first image on the computer screen reflected by an ellipsoidal surface with an eccentricity of approximately 0.5 and a radius of curvature at the apex of the surface of approximately 7.8 millimeters.
[0020] According to further aspects of the invention, the portion of the second image containing a representation is isolated. The comparison is made between the first image and the portion of the second image containing the human iris. In addition or alternatively, the determination can be made by searching the second image for a warped version of the first image. For example, a checkered pattern may be presented on the computer screen. The second image is then searched for a warped version of the checkered pattern.
[0021] According to further aspects of the invention, a third image is presented on the computer screen that is different than the first image. For example, the first image may be a checkered pattern and the third image may also be a checkered pattern but with a different arrangement of checkered squares. A fourth image is captured through the camera(s). The computer then aligns the second and fourth image. The computer then determines a difference image representing the difference between the second image and the fourth image. The portion of the difference containing an eye, and thus containing a reflection of the first and the third image are isolated. This may be found by identifying the portion of the difference image containing the greatest difference between the second and fourth images. A human eye is detected when the portion of the difference image is consistent with a reflection formed by a curved surface. For example, this can be detected determining the size of the portion containing a reflection of the first and third images; where the ratio between the image size and the image reflection size is greater than 10 to 1 then a human eye is detected. This ratio can be calculated for a particular application by dividing the distance between the user and the computer screen by approximately 3 to 6 millimeters, where the camera is at or near the computer screen.
[0022] According to still further aspects of the invention, a skin area is found in the second image and a determination is made as to whether the reflection of light from the skin area is consistent with human skin.
[0023] According to another aspect of the invention, a human eye is detected by presenting a first image on a computer screen positioned in front of a user. A first reflection of the first image off of the user is captured through a camera. The computer screen presents a second image on the computer screen positioned in front of the user. The camera captures a second reflection of the second image off of the user. The first and second images can be, for example, a checkered pattern of colors where the second image has a different or inverted arrangement. A computer compares the first reflection of the first image with the second reflection of the second image to determine whether the first reflection and the second reflection were formed by a curved surface consistent with a human eye. This comparison can be made, for example, by aligning the first reflection and the second reflection then calculating a difference between them to provide a difference image. The portion of the difference image containing a difference between a reflection of the first image and a reflection of the second image is identified. The size of this portion is determined. A human eye is detected when the ratio of the size of this portion to the size of the first and second image is approximately equal to a human-eye magnification level. Where the camera is located at or near the computer screen, the human-eye magnification level is determined by dividing the distance from the computer screen to the user by approximately 3 to 6 millimeters.
[0024] According to another aspect of the invention, a human eye is detected by obtaining a first image of a user positioned in front of a computer screen from a first perspective and obtaining a second image of the user positioned in front of the computer screen from a second perspective. A computer identifies a first portion of the first image and a second portion of the second image containing a representation of a human eye. The computer detects a human eye when the first portion of the first image differs from the second portion of the second image. For example, the computer may detect changes in specularity consistent with a human eye. For another example, the computer may align the first image with the second image and detect an area of residual misalignment. In this case, a human eye is detected if this area of residual misalignment exceeds a predetermined threshold.
[0025] According to further aspects of the invention, the first perspective is obtained by presenting a first graphic on the computer screen at a first location and instructing the user to view the first image. The second perspective is obtained by presenting a second graphic on the computer screen at a second location, different than the first, and instructing the user to view the second image.
[0026] According to another aspect of the invention, a human eye is detected by presenting one or more illuminators oriented to face a user. At least one camera is positioned proximate the illuminators. The camera(s) is oriented to face the user so that light emitted by the illuminators is reflected by the user and captured by the camera(s). The camera(s) also obtain a second image through at a different time than the first image. A computer detects a first position of a reflection in the first image and a second position of a reflection in the second image. The computer normalizes any positional change of the user in the first image and the second image based upon the first position and the second position. This normalizing includes compensating for motion during the time between the first image and the second image by using at least a translation motion model to detect residual motion of the position of the reflection. A human eye is detected when a change between the first image and the second image is consistent with reflection by a curved surface consistent with that of a human eye.
[0027] In another aspect of the invention, the invention includes a method of biometric recognition that associates face and iris imagery so that it is known that the face and iris images are derived from the same person. The methodology allows face acquisition (or recognition) and iris recognition to be associated together with high confidence using only consumer-level image acquisition devices.
[0028] In general, the inventive method of biometric recognition that associates face and iris imagery includes a method of biometric recognition. Multiple images of the face and iris of an individual are acquired, and it is determined if the multiple images form an expected sequence of images. If the multiple images are determined to form an expected sequence, the face and iris images are associated together. If the face and iris images are associated together, at least one of the iris images is compared to a stored iris image in a database. Preferably, the iris image comparison is performed automatically by a computer. Additionally or in the alternative, if the face and iris images are associated together, at least one of the face images is compared to a stored face image in a database. Preferably, the face image comparison is performed manually by a human.
[0029] Preferably, the acquiring of both face and iris images is performed by a single sensing device. That single sensing device is preferably a camera that takes multiple images of a person's face. Optionally, a midpoint of the camera's dynamic range is changed while taking the multiple images of the person's face. In addition or in the alternative, the position of the user relative to the camera is changed while taking the multiple images of the person's face. In addition or in the alternative, the zoom of the camera is changed while taking the multiple images of the person's face. Preferably, the acquiring of images occurs at a frame rate of at least 0.5 Hz.
[0030] To prevent fraudulent usage of the system (e.g., a person inserting a photo of someone else's iris into the field of view), at least one imaging parameter is determined from the multiple images acquired, and the at least one imaging parameter determined from the multiple images is compared to at least one predetermined expected imaging parameter. If the at least one imaging parameter determined from the multiple images is significantly different from the at least one predetermined expected imaging parameter, then it is determined that the multiple images do not form an expected sequence. Regarding the at least one imaging parameter, it may include at least one of determining if the accumulated motion vectors of the multiple images is consistent with an expected set of motion vectors; or ensuring that the iris remains in the field of view of all of the multiple images. This preferably takes places at substantially the same time as the acquiring step. If it is detected that at least one of i) inconsistent accumulated motion vectors or ii) that the iris is not in the field of view of all of the multiple images, then an error message is generated and the acquisition of images ceases and is optionally reset.
[0031] Because the face and the iris have very different reflectivity properties, the imaging device that captures both face and iris images must be adjusted accordingly. As such, preferably, the sensitivity of the camera is altered between a first more sensitive setting for acquiring iris images and a second less sensitive setting for acquiring face images. For example, the altering of the sensitivity may include alternating back and forth between the first and second settings during the acquiring step. This alternating step may be performed for every image so that every other image is acquired under substantially the same first or second setting. Whatever the timing of the altering of the sensitivity of the camera may be, how the altering may be accomplished may include at least one of the following: adjusting the gain settings of the camera; adjusting the exposure time; or adjusting the illuminator brightness. Preferably, the first more sensitive setting is substantially in a range of 1 to 8 times more sensitive than the second less sensitive setting.
[0032] Preferably, the acquiring step of the inventive method is performed until at least one face image suitable for human recognition is acquired and at least one iris image suitable for computer recognition is acquired. The acquisition of the at least one suitable face image is preferably required to occur within a predetermined amount of time of the acquisition of the at least one suitable iris image, either before or afterwards.
[0033] More generally, the inventive method of biometric recognition includes the steps of acquiring at least one non-iris image suitable for human recognition, and acquiring at least one iris image suitable for computer recognition within a predetermined period of time from the non-iris image acquiring step to ensure that both suitable images are from the same person. The non-iris image includes at least one of a body image, a face image, an identification code image, or a location image.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures and accompanying drawings and in which like reference numerals refer to similar elements and in which:
[0035] FIG. 1 is a functional block diagram of one preferred system used to detect a human eye.
[0036] FIG. 2 is a flow chart showing one preferred method of detecting a human eye.
[0037] FIG. 3 is a flow chart showing another preferred method of detecting a human eye.
[0038] FIG. 4 is a sequential schematic diagram illustrating a biometric recognition method that associates an iris image with a face image in accordance with an embodiment of the invention.
[0039] FIG. 5 is a flow chart illustrating a method for associating face and iris imagery in a sequence in accordance with an embodiment of the invention.
[0040] FIG. 6 is a sequential schematic diagram illustrating a biometric recognition method that associates an iris image with a face image using multiple sensors in accordance with an embodiment of the invention.
DETAILED DESCRIPTION
[0041] In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of invention described herein. It will be apparent, however, that embodiments of the invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the description of embodiments of the invention. It should also be noted that these drawings are merely exemplary in nature and in no way serve to limit the scope of the invention, which is defined by the claims appearing hereinbelow.
Functional Overview
[0042] In iris recognition applications, the iris is imaged behind the transparent corneal surface which has a particular convex shape. Light is also typically reflected off the cornea itself and back into the imager. In addition, the retinal surface is imaged through the pupil although it typically appears dark due to the relatively small amount of light that is returned to the imager from it. In order to determine whether a detected iris is live, parameters of the geometrical and/or photometric relationships and/or properties of the iris, retina and cornea determined. The reflective properties of a human eye are detailed at length in “The World in an Eye,” published by Ko Nishino and Shree K. Nayar, in IEEE Conference on Pattern Recognition , Vol 1, pp 444-451, June 2004, which is incorporated by reference in its entirety. In the present invention, using these reflective parameters, a determination is made as to whether an eye is live or not. Following the methods disclosed below, various components and their configuration in an iris recognition system can be varied in order to optimize performance for specific applications where it is easier to modify some configuration parameters compared to others.
[0043] More specifically, preferred techniques are discussed for determining whether an image detected through a camera is a live, human eye or a false representation such as a photograph. One or more images are presented on a computer screen positioned in front of a user. To deter attempts at spoofing, the image used for this determination may vary. Images presented on the computer screen may include a solid color, a regular or warped checkered pattern, random noise, etc. In addition, a number of different images may be presented in quick succession so that a person is unable to tell which image is being used for this determination, and is unable to predict which image will be displayed at which time. One or more cameras are positioned near the computer. The cameras are positioned to face a person in front of the computer screen. Due to the relatively sharp curvature of the human eye and particularly the cornea, the image projected on the computer screen will be reflected back and captured by the cameras.
[0044] The captured image may then be analyzed to determine whether it is consistent with an image reflected by a human eye. A number of methods may be used for this purpose. For example, the image reflected by the cornea and captured by the camera will appear substantially smaller than the image presented on the computer screen. A threshold level of magnification is set based upon the distance to the person's eye and the average radius of curvature for a human eye. If the captured image contains a reflection of the image presented on the computer screen and it is consistent in size with the expected size of this reflection, a human eye will be detected. This deters spoofing with a photograph because the flat surface of a photograph will not provide the substantial reduction in size caused by a reflection off the surface of the cornea. A number of other methods and variations can be used to make this same determination. These are explained in further detail below.
Configuration
[0045] FIG. 1 shows one preferred configuration of components. The cornea A is shown schematically as a curved surface. The iris B is shown schematically as a flat surface behind cornea A. For purposes of modeling a human eye, the surface shown as iris B could also represent the retinal surface. The cornea A and iris B are illuminated by one or more light sources I. In addition, a computer L includes a screen facing a user. The screen projects an image that may change with time. For example, the screen may project different wavelengths of light, each illuminating at different time instants. The illumination from items I and L are reflected off the cornea and directed into one or more cameras or imagers C. Illumination from the light sources I and the computer L are transmitted through the cornea, reflected off the iris or retina, re-transmitted through the cornea into the imager C. Since the cornea is transparent, imager C captures an image of the iris or retina and also has an image of the illumination I or projected image from computer L superimposed on top of it.
[0046] A human eye is identified by capturing image data using a particular configuration of a set of components such as those shown in FIG. 1 , and to compare the captured image data with data that has been predicted using knowledge of the expected geometrical or photometric configuration of the components. More specifically, two preferred comparison methods are described.
[0047] In the first method, imagery is captured using at least two different geometrical or photometric configurations of components. The captured image data (or features derived from the data) acquired using one configuration is then compared to the captured image data or derived features acquired using the second or further configurations. The computer calculates a set of change parameters that characterize the difference between the captured image data. The set of change parameters is compared with those change parameters that are predicted using knowledge of the expected change in geometrical or photometric configuration of the components. If the measured change parameters are different from the expected change parameters, then the geometric or photometric configuration of the corneal and iris or retinal surfaces are not as expected, for example the iris and cornea may appear to lie on the same surface. In this case it can be inferred that the iris is not live. Similarly, if the corneal surface is not consistent with a partially spherical surface, then again it is known that an iris is not live.
[0048] In another preferred method, imagery is captured using one geometric or photometric configuration of components. The captured image data (or features derived from the data) is compared with data that is predicted using absolute knowledge of the expected geometrical or photometric configuration of the components. For example, for a given image projected on the screen of the computer, a particular illumination pattern would be expected to appear on the surface of the cornea. While these two methods are described separately, they can be combined.
Method Comparing Two Configurations
[0049] Introduction:
[0050] With reference to FIG. 1 , consider a fixed geometry between a candidate iris B and a candidate cornea A, then changes in the geometrical arrangement and/or photometric properties of the illumination I or projected image L or position of camera C or position of the iris or corneal surfaces in coordinate system X, Y, T, where X, Y represent a standard 3D coordinate system and T represents time, results in change in the displacement or characteristics between or within the image of the iris B (or retina), and the image reflected off the cornea A. As shown, the screen of computer L can project a graphical image onto the curved surface of the cornea A. For example, one or more illuminators can illuminate the cornea and iris. Two cameras placed at two slightly different locations then image the iris B and cornea A. Due to the distance between the iris and the corneal surface, the specular reflection of the illuminator or graphical illumination on the cornea appears in a different location and can be warped or shifted with respect to the iris image in each camera view due to standard parallax and also the 3D curvature of the corneal surface, which acts similarly to a convex mirror lens due to its high curvature and reflectivity. This displacement or parallax can be measured and used to determine whether an eye has 3D structure that is consistent with the curvature of the cornea.
[0051] This process is further shown in FIG. 2 , which can be implemented using several methods. For example, one preferred method is shown in R. Kumar, P. Anandan, and KJ. Hanna, “Direct Recovery of Shape from Multiple Views: a Parallax Based Approach,” Proceedings of the 12th IAPR International Conference on Pattern Recognition, vol. 1, pp. 685-688, 1994, which is incorporated by reference in its entirety. The method shows how multiple images of a 3D scene can be processed to recover the 3D structure of a scene. In the first step, the multiple images are aligned together assuming a 3D planar model. For example, in the case of iris imagery, the 3D plane may be the iris surface itself. After this 3D planar alignment, any residual misalignment is indicative of structure that does not lie on the 3D plane. In the second step, this residual misalignment is measured.
[0052] In another method of measuring 3D structure, a full model of the scene is recovered without a 3D planar assumption. This type of method is disclosed in U.S. Pat. No. 5,259,040, titled “Method for determining sensor motion and scene structure and image processing system thereof,” which is incorporated herein by reference in its entirety. Notwithstanding that a specularity is not a real structure but an image artifact, its position in the image changes with viewpoint and therefore is detected by measuring the residual misalignment. If there is significant misalignment, as measured by thresholding the residual misalignment, then there is an indication that a 3D structure is present. Methods for thresholding residual misalignments are well-known and an example is given in “Recovering Motion Fields: An Evaluation of Eight Optical Flow Algorithms” B. Galvin, B. McCane, K. Novins, D. Mason, S. Mills, Proceedings of the British Machine Vision Conference (BMVC), 1998, which is incorporated herein by reference in its entirety. Given the corneal curvature, there is not only a residual misalignment, but the magnitude and distribution of the residual misalignment across the image is consistent with the 3D structure of the cornea. An example of modeling the reflected image off a curved surface is given in “Omnidirectional Vision,” by Shree Nayar, British Machine Vision Conference, 1998, which is incorporated herein by reference in its entirety. Another example of modeling the reflected image off the cornea is “The World in an Eye,” published by Ko Nishino and Shree K. Nayar, in IEEE Conference on Pattern Recognition, Vol 1, pp 444-451, June 2004, which is incorporated herein by reference in its entirety. In this latter case a camera observes imagery reflected off the cornea that is modeled as an ellipsoid. It is shown how the deformation introduced by the ellipsoid can be removed in order to provide a standardized perspective image. This standardized perspective image can then be processed using standard 3D structure recovery algorithms, as described earlier in this specification. Parameters for the shape of the cornea are well known. For example, the Gullstrand-LeGrand Eye model notes that the radius of the cornea is approximately 6.5 mm-7.8 mm. In another example, in “Adler's Physiology of the Eye: Clinical Application,” Kaufman and Alm editors, published by Mosby, 2003, the radius of curvature at the apex of the cornea is noted to be approximately 7.8 mm and the eccentricity of the ellipsoid is approximately 0.5. The same model that removes the deformation introduced by the corneal surface can be used in reverse in order to introduce the expected deformation into a standard geometrical pattern (such as a checkerboard) that can be presented onto the screen. When this deformed image is reflected off the cornea, it is substantially non-deformed so that the image acquired by the camera is simply the standard geometrical pattern. This simplifies the image processing methods that are required for detecting the patterns in the acquired imagery.
[0053] In another example implementation, the illumination screen or device can be located close to one of the cameras. The reflection off the retinal surface appears brighter in the camera located closer to the imager due to the semi-mirrored surface of the retina, and this also indicates whether an eye has the appropriate geometric and photometric properties. This approach takes advantage of the “red-eye-effect” whereby a light source is reflected off the retina and directly into the camera lens. If a second light source is placed at a more obtuse angle to the eye and camera, then less light will be reflected off the retina, although a similar quantity of light will be reflected off the face and other surfaces of the scene that scatter light in all directions (such a surface is Lambertian). Lambertian reflectance is described in Horn, “Robot Vision,” MIT Press, pp. 214-315, which is incorporated herein by reference in its entirety.
[0054] Further methods that exploit configuration changes are described below. The methods are separated into two steps: (1) illumination control and image acquisition; and (2) measuring deformation or change in characteristics. Further examples of these two steps are now described.
[0055] Illumination Control and Image Acquisition:
[0056] In steps P and Q in FIG. 2 , images are acquired using a particular configuration of the candidate cornea A and iris B (or retina), the illumination from light source I and/or the screen on computer L, one or more imagers C and/or orientation or position X, Y of the candidate corneal and iris or retinal surfaces at a time T. In steps R and S, images are acquired using a different configuration of the same elements also at a time T. An example of how a different orientation X, Y is obtained is by imaging the candidate person at two or more locations as the person walks or moves through a space. Steps (P, Q) and (R, S) may occur sequentially (T is different in this case) or simultaneously (T is equal in this case). An example of a sequential method is to use a single camera C but to modify the geometric or photometric arrangement of the light source I or image projected on the screen of computer L. By projecting an image having a geometrical pattern, the overall security of the system is dramatically improved because the geometrical pattern can be varied randomly under computer control, and because a geometrical pattern reflected by an eye is more difficult to spoof than a simple point source of light.
[0057] Another example of the sequential method is to create a projected image that varies over time—a video sequence for example. The video sequence may comprise a checkerboard pattern. For example, an example projection may have 4×4 black or white squares shown on the screen in a random binary arrangement. The squares may be pre-deformed as described above so that the reflected image off the cornea is close to a perfect checkerboard pattern.
[0058] Another example of a sequential method takes advantage of any combined motion of the cornea A and iris or retinal surfaces B. As the candidate cornea and iris or retina move through 3D space over time, different images are acquired at different time periods and due to the self-motion of the surfaces, the geometry between the said components changes. An example of a simultaneous method is to keep the image or light source fixed, but to have two cameras that acquire images from slightly different locations.
[0059] Measuring Deformation or Change in Characteristics:
[0060] The images captured from steps Q and S in FIG. 2 are then sent to a module that measures the deformation or changes in characteristics between the image content due to reflection off the corneal surface and image content due to reflection off the iris or retina. There are many different methods for performing this step. In one preferred implementation, image alignment is performed using a hierarchical, iterative method such as described by Bergen et al., “Hierarchical Model-Based Motion-Estimation,” European Conference on Computer Vision, 1993, which is incorporated herein by reference in its entirety. For example, a translation model can be applied between the warped images W(Q) and the original images O(R). There are, of course, many other methods for performing alignment. A difference between the aligned images is then calculated. The aligned images are then filtered to enhance fine-frequency edges due to the checkerboard patterns and to reduce the magnitude of low frequency edges that may occur due to illumination changes elsewhere in the image. There are also many ways of filtering images in this way. One preferred example is described in “A Computational Approach to Edge Detection,” by John Canny, IEEE Transactions on Pattern Analysis and Machine Intelligence, Volume 8, Issue 6, 1986, which is incorporated herein by reference in its entirety. An image difference is then calculated between the aligned filtered images to further remove illumination changes and to highlight the difference between the first reflected filtered image and the second reflected filtered image. Next, template matching is performed to identify the unique pattern created by taking the difference of the filtered, reflected images. If such a pattern is located in the image of the correct size and correct deformation, then a live reflection off the cornea has been detected. There are many methods for detecting patterns in images. One preferred example is disclosed in U.S. Pat. No. 5,488,675, titled “Stabilizing Estimate of Location of Target Region Inferred from Tracked Multiple Landmark Regions of a Video Image,” and also U.S. Pat. No. 5,581,629, titled “Method for Estimating the Location of an Image Target Region from Tracked Multiple Image Landmark Regions,” both of which are incorporated herein by reference in their entirety.
[0061] The size of the pattern can also be predicted from the expected geometrical shape of the cornea. The detected size of the reflection can then be measured and used to determine whether the size is consistent with that of a human cornea. For example, it is known that the focal length of a convex mirror reflector is half the radius of curvature. Using standard lens equations, then 1/f=1/d0+1/d1, where f is the focal length, d0 is the distance of the screen from the cornea, and d1 is the distance of the reflected virtual image from the cornea. It is known from, for example, “Adler's Physiology of the Eye: Clinical Application,” Kaufman and Alm editors, published by Mosby, 2003, that the radius of curvature at the apex of the cornea is approximately 7.8 mm and the eccentricity of the ellipsoid shape of the cornea is approximately 0.5. The focal length of the corneal reflective surface at the apex is therefore half this focal length: approximately 3.9 mm. Using the ellipsoidal model, the radius of curvature of the cornea at a radial distance of 6 mm from the apex of the cornea can be computed to be approximately 9.6 mm. The focal length of the corneal reflective surface in this region is therefore approximately 4.8 mm. If the cornea is situated approximately 150 mm from the computer screen, then from the standard lens equation above, d1 can be computed to be 4.0 mm at the apex, and 4.96 mm at a radial distance of 6 mm from the apex of the cornea. The magnification is computed to be d1/d0=4.0/150=1/37.46 at the apex of the cornea, and 4.96/150=1/30.25 at a radial distance of 6 mm from the apex of the cornea. This means that the cornea has the effect of reducing the size of the graphic on the computer screen by a factor of 37.46 to 30.25 in this case, over different regions of the cornea, whereas the magnification expected if the reflective surface is flat is 1. If the detected graphic is significantly larger or smaller than the reduction factors 37.46 to 30.25, then the curvature of the cornea is inconsistent with that of a live person.
[0062] If the local radius of curvature of the cornea is substantially less then the distance of the cornea to the computer screen, then the magnification can be simplified to be R/(2×d1), where d1 is the distance from the cornea to the computer screen and R is the local radius of curvature of the cornea. Due to human variation, the radius of curvature of local regions of a cornea may lie within the bounds of 6 to 12 mm. The magnification therefore may lie in the range of 3/d1 to 6/d1.
[0063] In another example, if d1 lies within the range of 75 to 500 mm then using the parameters and the formula above, it is expected that the magnification is 1/12.5 to 1/166.7.
[0064] The distance d1 may be unknown, however, the ratio of the magnification at the apex of the cornea and the magnification elsewhere in the cornea is independent of the distance d1. For example, using the parameters above, the magnification ratio between the apex and a point 6 mm radially from the apex is (1/37.46)/(1/30.25)=0.807. At a distance of 4 mm radially from the apex, the expected magnification ratio is computed to be 0.909. The iris is approximately 11 mm in diameter, and therefore localization of the iris/sclera boundary can be used to identify the approximate location of any radial position of the cornea with respect to the apex.
[0065] In another example, consider the change in configuration caused by the movement of a person with respect to a camera and one or more illuminators or computer screens. The position of the reflection of the illuminators, or the detected shape and magnification of the computer screen, will change as the person moves. In one preferred implementation to detect this change, a sequence of images are acquired and image alignment is performed using a hierarchical, iterative method such as described by Bergen et al., “Hierarchical Model-Based Motion-Estimation,” European Conference on Computer Vision, 1993, which is incorporated herein by reference in its entirety. For example, a translation and zoom model can be applied between the warped images W(Q) and the original images O(R). In this case the motion of the user will be stabilized, and, for example, the image of the iris may be aligned throughout the sequence. Any residual motion is an indication of a change in the position of the reflection of the illuminators, or of a change in the shape and magnification of the computer screen, due to an eye consistent with that of a live person. For example, one preferred method of detecting the residual motion or change is shown in R. Kumar, P. Anandan, and KJ. Hanna, “Direct Recovery of Shape from Multiple Views: a Parallax Based Approach,” Proceedings of the 12th IAPR International Conference on Pattern Recognition, vol. 1, pp. 685-688, 1994, which is incorporated by reference in its entirety. In an alternate method, a nonparametric flow model as described in Bergen et al., “Hierarchical Model-Based Motion Estimation,” European Conference on Computer Vision, 1993, can be applied to detect residual motion.
[0066] In another example, consider the presentation of illumination of a particular wavelength, the recording of an image, and then presentation of illumination with a different wavelength and the recording of one or more additional images. Depending on the photometric properties of the material, the ratio of the digitized intensities between the images can be computed and compared to an expected ratio that has been previously documented for that material. The response of iris tissue has a unique photometric signature which can indicate whether the iris is live or not. Equally, the response of skin tissue has a unique photometric signature which can indicate whether the skin is live or not. This method can be implemented by acquiring two or more images with the computer screen projecting different wavelengths of light, such as red, green, and blue. These colors can be projected in a checkerboard or other pattern. For example, a first image may contain a red checkerboard pattern, and a second image may contain a blue checkerboard pattern. The methods described above can then be used to align the images together, and to detect the location of the eye or eyes by detecting the patterns reflected off the cornea. The iris and the sclera (the white area around the iris) are then detected. Many methods are known for detecting the iris and the sclera. For example, a Hough transform can be used to detect the circular contours of the pupil/iris and iris/sclera boundaries as explained by R. Wildes, “Iris Recognition: An Emerging Biometric Technology,” Proc IEEE, 85(9): 1348-1363, September 1997, which is incorporated herein by reference in its entirety. Intensities of the iris and sclera can then be sampled and used to measure the liveness of the eye. These ratios can be computed in several ways. In one preferred method, the ratio of the iris reflectance and the scleral reflectance is computed. This ratio is substantially independent of the brightness of the original illumination. The iris/scleral ratio is then computed on the other aligned images. This process can be repeated by measuring the scleral/skin ratio. The skin region can be detected by measuring intensities directly under the detect eye position, for example. Ratios can also be computed directly between corresponding aligned image regions captured under different illumination wavelengths. These ratios are then compared to pre-stored ratios that have been measured on a range of individuals. One method of comparison is to normalize the set of ratios such that sum of the magnitudes of the ratios is unity. The difference between each normalized ratio and the pre-stored value is then computed. If one or more of the normalized ratios is different from the pre-stored ratio by more than a pre-defined threshold ratio, then the measured intensity values are inconsistent with those of a real eye.
[0067] In yet another example, the user may be asked to fixate on two or more different locations on the computer screen while a single camera records two or more images. The specular reflection off the cornea will remain substantially in the same place since the cornea is substantially circular, but the iris will appear to move from side to side in the imagery. In order to detect this phenomenon, the alignment methods described above can be used to align the images acquired when the user is looking in the first and second directions. The high-frequency filtering methods and the image differencing method described above can then be used to identify the eye regions. The alignment process can be repeated solely in the eye regions in order to align the iris imagery. The residual misalignment of the specular image can then be detected using the methods described earlier.
Method Comparing One Configuration
[0068] Introduction:
[0069] In the previous section, images were captured using at least two different geometrical or photometric configurations of components. The captured image data (or features derived from the data) acquired using each configuration were compared to each other and a set of change parameters between the captured image data were computed. The set of change parameters were then compared with those change parameters that were predicted using knowledge of the expected change in geometrical or photometric configuration of the components. In a second method, imagery is captured using one geometric or photometric configuration of components. The captured image data (or features derived from the data) is compared with data that is predicted using absolute knowledge of the expected geometrical or photometric configuration of the components. Both the first and second methods can optionally be combined.
[0070] To illustrate an example of the second method, consider that the shape of the cornea results in a particular reflection onto the camera. For example, an image projected on the screen of computer L may be rectangular, but if the candidate corneal surface is convex then the image captured by imager C comprises a particular non-rectangular shape, that can be predicted from, for example, the ellipsoidal model described earlier in this specification. This particular reflected shape can be measured using methods described below, and can be used to determine whether the cornea has a particular shape or not. FIG. 3 shows the steps of the second method. The second method can be implemented in several ways, and the components for one approach were described above. That approach comprises the first step of projecting a random graphic pattern on a computer screen, which may optionally be pre-deformed such that the reflected image off the cornea is substantially free of deformation. The second step is then to perform pattern recognition on the image to detect the reflected graphic pattern. The expected radius of curvature of the cornea is used to compute the expected deformation and expected magnification as described above. An eye is determined to be live if the random pattern is detected at approximately the correct size and with the expected deformation. A method for performing the detection of the pattern was described above.
[0071] To illustrate the combination of the first and second methods, consider the previous example but also consider that the projected image L changes over time. Both the absolute comparison of the reflected image with the expected absolute reflection as well as the change over time in the reflected image compared to the expected change over time can be performed to validate the geometrical relationship and/or photometric relationship between or within the corneal and iris or retinal surfaces.
[0072] Optimizing Performance:
[0073] As set forth above, the number and configuration of the various system components that include (I, L, C, A, B, (X, Y, T)) can vary widely, and the methods are still capable of determining the parameters of the geometrical and/or photometric relationship between or within either surface A, B which are the corneal and iris or retinal surfaces. In order to optimize the particular configuration of the various system components, many factors in the optimization need to be included, for example: cost, size, and acquisition time. Depending on these various factors, an optimal solution can be determined. For example, consider an application where only one camera C can be used, the candidate corneal surface A and iris or retinal surface B is fixed, and only a projected light source from a computer L can be used. Using the first method, variation in the configuration may be derived from the remaining configuration parameters (X, Y, T) and L. For example, the surfaces may move in space and time, and imagery captured. In another example where the orientation and position of the eye (X, Y) is fixed, then the projected image L can be varied, and imagery acquired by camera C. Note that variation in all parameters can be performed simultaneously and not just independently. All variations provide supporting evidence about the parametric relationship between or within the corneal and iris/retinal surfaces that is used to determine whether an iris is live or not. If anyone of the measured variations does not equal the expected variation, then the iris is not live.
[0074] As mentioned above, it is well known that imagery of the iris can be reliably matched to previously recorded iris imagery in order to perform reliable verification or recognition. However since the iris patterns are not easily recognizable to a human, it is impossible to demonstrate to a user who has been rejected from any iris recognition system the reason for the rejection. On the other hand, if a face recognition system is used instead of an iris recognition system, it is easy to demonstrate the reason for rejection since face imagery can be easily interpreted by humans. However, automated face recognition systems are widely known to be much less reliable than iris recognition systems.
[0075] We propose a method whereby iris imagery is acquired and used for automatic iris matching, face imagery is acquired at least for the purposes of human inspection generally in the case of rejection, and where the face and iris imagery is acquired and processed such that it is known that the face and iris imagery were derived from the same person. We present a design methodology and identify particular system configurations, including a low-resolution single camera configuration capable of acquiring and processing both face and iris imagery so that one can confirm and corroborate the other, as well as give assurances to the user who cannot properly interpret an iris image. We first present a single-sensor approach.
[0076] Single-Sensor Approach:
[0077] Most methods for acquiring images of the face or iris use camera imagers. The simplest method for acquiring imagery of the face and iris with some evidence that the imagery is derived from the same person is to capture a single image of the face and iris from a single imager. However, in order to capture the face in the field of view, the number of pixels devoted to the iris will be quite small, and not typically sufficient for iris recognition. High resolution imagers can be used, but they are expensive and not as widely available as low-cost consumer cameras. Also, the albedo (reflectance) of the iris is typically very low compared to the face, and this means that the contrast of the iris is typically very small in cases where the full face is properly imaged within the dynamic range of the camera. It is generally much more difficult to perform reliable iris recognition using a low-contrast image of the iris. It is also more difficult to implement reliable anti-spoofing measures for iris recognition when the acquired data is low resolution or low contrast.
[0078] We propose a method whereby multiple images of the face and iris are collected, the images are processed, and a determination is made as to whether the face and iris images are part of an expected sequence of images. If a determination can be made that the images were collected as part of an expected sequence of images, then a determination can be made that the face and iris imagery are of the same person. The multiple images may be collected under different imaging conditions, for example: change in the midpoint of the camera's dynamic range; change in position of the user; and/or change in zoom of the camera.
[0079] For example, FIG. 4 illustrates the second and third scenarios. A user “A” may present themselves to a simple consumer web-camera “C”. As the user moves towards or away from the web-cam, images of the face and iris are acquired. S0, S10, S20, S30 are example images from the acquired sequence. When the user is close to the web-cam, then the iris is imaged optimally. The resolution and contrast of the iris will be substantial which is helpful to optimize recognition, and also makes anti-spoofing measures easier to implement. When the user is far from the web-cam, a full face image will be acquired.
[0080] Associating Face and Iris Imagery:
[0081] We now describe a method for associating face and iris imagery in a sequence. FIG. 5 shows the approach. The first step is to have knowledge of the expected imaging scenario “I”. For example, in the example above, the expected imaging scenario is that the user will approach or move away from the camera (as shown, for example, in FIG. 4 ). Next, the image sequence is acquired as shown in step A. Next, image processing is performed between the images in the sequence to produce parameters as shown in step M. For example, continuing with the example above, motion can be computed between frames and a similarity (zoom, translation, rotation) model of motion can be fit. The expected set of parameters is derived in step E using knowledge of the imaging scenario. For example, we would expect to see a substantial zoom component in the motion analysis parameters as the user approaches or moves away from the camera, and we would expect there to be a continuous single motion and not two motions. For example, if the user tried to insert a picture of a second person into the camera's field of view as they moved away from the camera, then two motions would be present—one due to the user moving back, and the second from the insertion of the picture into the view. The measured and expected parameters are then compared in step D. If there is a significant difference between the expected and measured parameters, then the face and iris imagery cannot be associated. If there is not a significant difference, then the face and iris imagery can be associated.
[0082] It is important that the method track and perform alignment from the image at or close to the iris image used for biometric recognition to another image taken later or earlier in the sequence of images. Ideally but not necessarily, image tracking would be from the actual image used for iris matching. However, using the very same image used for iris matching is not required. The key constraint is that the iris image at or near the matched iris image has to be close enough in time to prevent a user from suddenly switching the camera from one person to the next, or from inserting a picture of someone else's iris or face, without detection. If the frame rate were as low as 0.5 Hz, then it is plausible to see that this could happen. A preferred time interval between frames is thus 2 seconds or less.
[0083] The image acquiring process of the method must include acquiring an iris image suitable for biometric recognition. The determination of what constitutes a suitable image can be made automatically by known methods. Once that suitable iris image has been determined to have been acquired, as mentioned above, tracking and alignment must be performed between at least that iris image (or a nearby image in the sequence) and another image, e.g., the image at the other end of the sequence where the iris image is at one end. The other image is described as being preferably an image of the user's face, however it need not be so limited. The other image used for tracking an alignment could be an image of the whole body of a person, a place, a face, an ID number on a wall, or pretty much anything that allows for confirmation of the user's iris image in a manner that is perceptible to the human eye. The selection of that other image can be accomplished in one or more of several ways. For example, it could be selected manually (e.g., by a button press holding the device far away or at a target), and then the end of the sequence (where the iris imagery is acquired) is detected automatically. As another example, it could also be selected via an automatic face finding algorithm, or an automatic symbol detection algorithm. The selection can also be made using the zoom difference between a face image and an iris image, since if an iris image is selected, then taking an image at least 10 times zoomed out and in the same location will result in the face.
[0084] Regarding this last method, if an iris image is selected, one can be sure there is a face in the image without doing processor-intensive face finding if the zoom and position parameters of images in the sequence are examined. If the position hasn't moved by more than the field of view of the camera, and the zoom is a certain amount, then the face is surely in the field of view. Put another way, if there are N pixels across the iris when matched (the ISO standard for N is in the range of 100 to 200 pixels), and P pixels between the eyes in the face image are desired (also 100-200 pixels, per ISO standards), then we wait until the zoom difference measured is approximately 10, since the ratio of the typical iris to the typical eye separation is about 10.
[0085] Example Implementation Methods:
[0086] There are many methods for performing steps M, E, C, D in FIG. 5 . We present a preferred set of methods as an example. First, if the images acquired in step A are labeled 11, 12, 13, 14 etc., then a difference image sequence D1, D2, D3, D4 is computed by subtracting adjacent frames. For example, D1=12−11, and D2=13−12 etc. If the camera sensor is stationary, then this differencing removes the background from processing meaning that all resultant intensities in the sequence are due to the moving person. Note that this approach is only used if only the user is moving. In cases of a lens that zooms, this step would not be performed since the background also moves. Second, flow analysis is performed between successive image pairs. There are many methods known in the art for performing flow analysis. An example is Bergen et. al, “Hierarchical Motion Analysis”, European Conference on Computer Vision, 1992. We compute both flow values and also confidence measures in the flow at each location in the image for each image pair consisting of a reference and an inspection image. Third, we fit a similarity transform (translation, zoom and rotation) model to the recovered flow vectors, accounting for the confidence values using a lest-squares model-fit method. For example in the case of a moving user, regions due to the background have zero confidence since there are no intensities due to the use of the first image differencing step. A RANSAC fitting algorithm that is robust to outliers can be used [M. A. Fischler, R. C. Bolles. Random Sample Consensus: A Paradigm for Model Fitting with Applications to Image Analysis and Automated Cartography. Comm. of the ACM, Vol 24, pp 381-395, 1981.]. Fourth, once the model has been fit, we warp the inspection image to the reference image using the model and compute the residual misalignment or difference between the warped image and the reference image. For example, we can re-compute the flow analysis between the warped image and the reference image. Any motion that is inconsistent with a person moving towards or away from the camera (such as the motion from a person's picture being inserted into the sequence) will be measured. We then histogram the magnitudes of these residual intensities, and repeat the entire process for every successive image pair in the sequence. For additional sensitivity, we also repeat the motion analysis between non-adjacent image pairs using the computed cascaded motion parameters between frames as a seed to begin the motion analysis. Finally, we inspect the histogram of the residual motions or differences. If there are any residual motions or differences above a threshold value, then we declare that the face and iris imagery cannot be associated.
[0087] In addition, we can use the recovered model parameters to ensure that a face image has actually been acquired. For example, an iris finder algorithm may have located the iris precisely. The motion parameters from the model-fitting process defined above can be cascaded in order to predict whether a full face image is in fact visible in any part of the sequence by predicting the coverage of the camera on the person's face for every image with respect to the location of the iris. For example, we may measure a translation T and a zoom Z between an image containing the iris at location L and a second image.
[0088] We can then predict the face coverage on the second image using the parameters T, Z and L and the typical size of a person's head compared to their iris. For example, an iris is typically 1 cm in diameter and a person's head is typically 10 cm in diameter. A zoom factor of approximately 10 between the iris image and the second image will indicate that the second image is at least at the correct scale to capture an image of the face. The translation parameters can be inspected similarly. This inspection method can also be used to stop the acquisition process given an initial detection of the iris.
[0089] Multi-Sensor Approach:
[0090] The single-sensor approach above can be extended to the use of multiple sensors. For example, FIG. 6 shows two sensors focused on a person.
[0091] One imager may have higher resolution than the other. We now can perform image processing both within a single sequence and also between the two sequences. For example, if one imager is low resolution and the second imager is high resolution, then the parameters of motion recovered from each image sequence using the methods described above will be directly related—for example if the imagery moves to the right in the low-resolution imager, then the imagery will move to the right at a faster speed in the second imager. If this does not occur, then the imagery being sent from each imaging device are likely not derived from the same person. This is important in non-supervised scenarios where video connections to the two sensors may be tampered with. In addition to comparison of motion parameters between sequences, images themselves can be compared between sequences. For example, if the approximate zoom factor between the high and low resolution cameras is known, then the high resolution image can be warped to the resolution of the low resolution image, and an image correlation can be performed to verify that the imagery from the two or more sensors are in fact derived from the same scene.
[0092] In the foregoing specification, embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. Thus, the sole and exclusive indicator of what is the invention, and is intended by the applicants to be the invention, is the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction. Any definitions expressly set forth herein for terms contained in such claims shall govern the meaning of such terms as used in the claims. Hence, no limitation, element, property, feature, advantage or attribute that is not expressly recited in a claim should limit the scope of such claim in any way. The summary, specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
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A method of biometric recognition is provided. Multiple images of the face or other non-iris image and iris of an individual are acquired. If the multiple images are determined to form an expected sequence of images, the face and iris images are associated together. A single camera preferably acquires both the iris and face images by changing at least one of the zoom, position, or dynamic range of the camera. The dynamic range can be adjusted by at least one of adjusting the gain settings of the camera, adjusting the exposure time, and/or adjusting the illuminator brightness. The expected sequence determination can be made by determining if the accumulated motion vectors of the multiple images is consistent with an expected set of motion vectors and/or ensuring that the iris remains in the field of view of all of the multiple images.
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BACKGROUND OF THE INVENTION
Although it is desirable, in angiographic examination of human vascular portions injected with a contrast medium, to scan with an X-ray beam rotating around the patient so as to produce a series of X-ray images at successive angles, a remaining problem is that available rotational X-ray scanners do not rotate fast enough to complete a substantial angular scan, e.g. up to 180 degrees, during the short period while the contrast medium remains in the vascular body portion under examination, e.g. 3 seconds. Extending the time and the amount of injected contrast medium increases the risk to the patient from the medium's toxicity. Available X-ray systems suitable for angiographic examination are limited to accelleration within 360 degrees.
Accordingly it is the object of the present invention to provide an apparatus and method which will make possible an angiographic scan of a human vascular portion though a wide angle during the short period that an acceptably safe injection of contrast medium remains in the portion.
SUMMARY OF THE INVENTION
According to the invention apparatus in an X-ray system for angiographic examination of a patient comprises a rotatable support; a motor for turning the support about a central axis; radiation means including an X-ray source for exposing a portion of a patient on the central axis, and an X-ray receptor generating video signals representing an image of the exposed patient volume, the source and receptor being aligned on a common radiation axis through and isocenter on the central axis; means on the rotatable support mounting the source and receptor at opposite sides of the central axis; and a programmer controlling the motor and the radiation means; wherein the X-ray source radiates a cone-shaped beam through a three-dimensional volume of the patient; the receptor generates a two-dimensional video image signal; and the programmer include a timer energizing the X-ray source at a continuous succession of predetermined angular positions of the rotating support and radiation axis while the patient is stationary, so as to produce a plurality of two-dimensional images of the patient volume at successive angles.
Further the invention involves a method of angiographic examination of a patient comprising disposing a vascular volume of a stationary patient on the radiation axis of a beam of conical X-rays rotating around a central axis through the patient; injecting a unit of X-ray contrast medium into the patient volume while the X-ray beam is rotating; energizing the X-ray beam in a scan of a continuous succession of rotational angles of the radiation axis to expose the patient while stationary and the single unit of contrast medium remains in the volume; and generating video signals representing the patient exposure.
DRAWING
The single drawing FIGURE is an end elevation of a rotary X-ray scanning apparatus according to the invention, shown partly in section, and with diagrammatic electrical wiring to a data processing programmer.
DESCRIPTION
As shown in the drawing, rotary X-ray apparatus is mounted on a floor base 1 from which a two-armed cradle 2 extends upwardly. At the upper end of each cradle arm is a rotary bearing 3 holding a circular gimbal 4 which may turn through a limited angle around a tilt axis A1. The gimbal carries four rollers 6 which rotatively support a large, hollow inner ring 7, the ring being driven by a motor M having a pulley 8 for a belt 9, as shown and described in detail in U.S. Pat. No. 4,426,725. The inner ring rotates continuously and repeatedly through 360 degrees about a central axis A2. The hollow interior space 11 of the inner ring 7 is closed by an outer circular wall 12, end walls 13 of which one is visible, and an X-ray transparent inner circular wall 14 around a central opening 16. The central opening admits a patient P lengthwise on a table T along the central axis A2. Attached to the patient are a cardiographic electrode 17 and a catheter 18 with a motorized pump 19 for injecting a contrast medium in to a selected vascular portion of the patient under examination.
Within the hollow ring 7 are an X-ray tube X and an image intensifier I located on a radiation axis A3 which intersects the rotational axis A2 of the ring and the tilt axis A1 of the gimbal at an isocenter C within the patient. The X-ray tube X has a high voltage anode K and a grounded anode A. The tube is of a known high power type (e.g. 15 kilowatts) having a focal spot of about 0.3 to 0.5 millimeters on a high speed rotating anode from which X-rays are radiated in a cone shaped beam along the radiation axis to the image intensifier I. Typically the distance from the anode to the image intensifier is 40 inches, and to the isocenter is 20 inches. This allows an image intensifier with a 7 or 8 inch on-axis field of view and an image of 512 or 1024 pixels squared, yielding a high detail resolution and a 2:1 enlargement. By tilting the gimbal 4 the fore and aft angle of the radiation axis through the patient may be adjusted.
Operation of the system is controlled by a computer or programmer 21 with a three-phase voltage supply 22. The programmer comprises a timer 23 which receives heart pulse signals from the electrode 17 attached to the patient P and starts the inner ring drive motor M. After allowing time for the motor to bring the inner ring to desired speed, or when otherwise programmed, the timer energizes the catheter injecting contrast medium into a vascular portion of the patient. The timer then immediately triggers the high voltage supply 24 for the X-ray tube causing the supply to apply a series of high voltage pulses to the tube so that it emits a series of very short X-ray bursts through the patient to the image intensifier I. The high voltage supply is connected to the X-ray tube through the sliding contacts of brushes or slip rings 15. Similarly slip rings conduct the video signals generated by the image intensifier in response to the X-ray bursts to a processing section 26 of the programmer. The processed video signals are saved in a storage memory 27 for transmission to a video display 28 or recorder 29 as selected by the examining physician.
The X-ray tube is of the strobe type, capable of using very high power, eg. 15 to 50 kilovolt, high voltage pulses of short duration, e.g. 0.008 to 0.010 seconds. Its rotating anode has a focal point of close to 0.03 millimeter diameter, and emits a cone shaped beam which forms a two-dimensional image at the image intensifier. (This is to be contrasted with the fan shaped beam and one dimensional, line image of a computer assisted (CAT) scanner). After the timer 23 initiates injection of contrast medium into the patient it will stay within the vascular portion of the patient under examination only about three seconds. During these three seconds the motor M has a speed to rotate the inner ring 90 to 180 degrees and is of the vector or synchro type whose phase angle or position is controlled by the timer 23. The timer also controls the pulse rate of the high voltage supply 24 so that it supplies a short burst of X-rays at a preselected angle of the radiation axis A3 relative to the patient. Preferably ninety 8 to 10 millisecond X-ray pulses are emitted at thirty pulses per second during the three second rotation by the inner ring through 90 to 180 degrees of angle.
Surprisingly such rapid movement of the X-ray beam does not increase blurring of the intensifier image or its video signals beyond the unavoidable penumbra inherent in the X-ray shadow on the image intensifier. The unexpectedly clear image of 90 to 180 frames of video signals per 3 second scan of the radiation axis can be enhanced by making one scan before contrast medium injection, and, by a known data process subtracting that background image of the patient from the subsequent images after contrast medium injection. Moreover successive pairs of images provide a three-dimensional viewing of the patient.
It should be understood that the present disclosure is for the purpose of illustration only, and that the invention includes all modifications and equivalents falling within the appended claims.
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An X-ray system scans the vascular portion of a human patient by a series of rapidly pulsed exposures from an X-ray tube rotated continuously through 360 degrees around the patient. The tube emits a cone-shaped beam through the patient to a receptor which generates a corresponding series of two-dimensional video images of the patient from successive angles.
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TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to the field of devices and methods for shaping human hair, and more particularly to devices and methods for binding human hair in a styled position.
PROBLEM STATEMENT
Interpretation Considerations
[0002] This section describes the technical field in more detail, and discusses problems encountered in the technical field. This section does not describe prior art as defined for purposes of anticipation or obviousness under 35 U.S.C. section 102 or 35 U.S.C. section 103. Thus, nothing stated in the Problem Statement is to be construed as prior art.
Discussion
[0003] Because hair receives a great deal of attention in the human quest for beauty and attention, inventors frequently look for new ways to style hair. In that quest, a number of mechanical devices, such as hair-clips, and a number of styling methods, such as braiding, have been developed. Accordingly, the present invention provides an apparatus and method for styling human hair in a new manner.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Various aspects of the invention, as well as an embodiment, are better understood by reference to the following detailed description. To better understand the invention, the detailed description should be read in conjunction with the drawings and tables, in which:
[0005] FIG. 1 illustrates an inventive pony tail wrap.
[0006] FIG. 2 shows the pony tail wrap attached to a pony tail with the strip member shown in a first extended open position.
[0007] FIG. 3 shows the pony tail wrap attached to a pony tail with the strip member shown in a second cylindrical position.
[0008] FIG. 4 illustrates the pony tail wrap with the pony tail looped back through the pony tail wrap.
DETAILED DESCRIPTION OF THE INVENTION
Interpretation Considerations
[0009] When reading this section (which describes an exemplary embodiment of the best mode of the invention, hereinafter “exemplary embodiment”), one should keep in mind several points. First, the following exemplary embodiment is what the inventor believes to be the best mode for practicing the invention at the time this patent was filed. Thus, since one of ordinary skill in the art may recognize from the following exemplary embodiment that substantially equivalent structures or substantially equivalent acts may be used to achieve the same results in exactly the same way, or to achieve the same results in a not dissimilar way, the following exemplary embodiment should not be interpreted as limiting the invention to one embodiment.
[0010] Likewise, individual aspects (sometimes called species) of the invention are provided as examples, and, accordingly, one of ordinary skill in the art may recognize from a following exemplary structure (or a following exemplary act) that a substantially equivalent structure or substantially equivalent act may be used to either achieve the same results in substantially the same way, or to achieve the same results in a not dissimilar way.
[0011] Accordingly, the discussion of a species (or a specific item) invokes the genus (the class of items) to which that species belongs as well as related species in that genus. Likewise, the recitation of a genus invokes the species known in the art. Furthermore, it is recognized that as technology develops, a number of additional alternatives to achieve an aspect of the invention may arise. Such advances are hereby incorporated within their respective genus, and should be recognized as being functionally equivalent or structurally equivalent to the aspect shown or described.
[0012] Second, the only essential aspects of the invention are identified by the claims. Thus, aspects of the invention, including elements, acts, functions, and relationships (shown or described) should not be interpreted as being essential unless they are explicitly described and identified as being essential. Third, a function or an act should be interpreted as incorporating all modes of doing that function or act, unless otherwise explicitly stated (for example, one recognizes that “tacking” may be done by nailing, stapling, gluing, hot gunning, riveting, etc., and so a use of the word tacking invokes stapling, gluing, etc., and all other modes of that word and similar words, such as “attaching”).
[0013] Fourth, unless explicitly stated otherwise, conjunctive words (such as “or”, “and”, “including”, or “comprising” for example) should be interpreted in the inclusive, not the exclusive, sense. Fifth, the words “means” and “step” are provided to facilitate the reader's understanding of the invention and do not mean “means” or “step” as defined in §112, paragraph 6 of 35 U.S.C., unless used as “means for—functioning—” or “step for—functioning—” in the Claims section. Sixth, the invention is also described in view of the Festo decisions, and, in that regard, the claims and the invention incorporate equivalents known, unknown, foreseeable, and unforeseeable. Seventh, the language and each word used in the invention should be given the ordinary interpretation of the language and the word, unless indicated otherwise.
[0014] It should be noted in the following discussion that acts with like names are performed in like manners, unless otherwise stated. Of course, the foregoing discussions and definitions are provided for clarification purposes and are not limiting. Words and phrases are to be given their ordinary plain meaning unless indicated otherwise. The numerous innovative teachings of present application are described with particular reference to presently preferred embodiments.
DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 illustrates an inventive hair wrap 100 . The hair wrap 100 is generally comprised of a hair tie 110 that is coupled to a strip member 130 . Generally, a hair tie (or ponytailer, ponytail holder, or hair band) is a small, stretchy band used to fasten hair, particularly long hair, into a hairstyle (usually a ponytail). Typically, a hair tie comprises an elastic interior and a cover of cloth or other material to reduce the tendency of hair to get caught in the elastic and pulled out of one's scalp. Accordingly, it can be said that the hair tie 110 typically has an elastic interior portion and a non-abrasive covering such as nylon, silk, or fabric, for example.
[0016] The strip member 130 is a free spontaneously-curved anisotropic strip positionable in a first generally planar position, and a second generally cylindrical position. When in the second generally cylindrical position, the strip member is said to have an interior surface 132 and an exterior surface 134 which is in some embodiments ornamental, and the hair tie 110 is attached to the interior surface 132 of the strip member. The strip member 130 may be made of any material that has anisotropic properties, and is preferably metal or a plastic.
[0017] Accordingly, a user may perceive the strip member 130 to be similar to a slap-bracelet (or snap bracelet). Generally, a slap bracelet is a bracelet consisting of layered, flexible stainless steel or plastic bistable spring bands sealed within a fabric or plastic cover. The bracelet can be straightened out, creating tension within the springy metal bands. The straightened bracelet can be slapped against the wearer's wrist, causing the bands to spring back to form a cylindrical shape that wraps around the wrist.
[0018] The hair tie 110 and the strip member 130 are attached via an attachment 120 , such as an adhesive. However, in alternative embodiments the attachment 120 is an attaching member that may be separately glued to the interior surface 132 of the strip member 130 , or may be integrally formed with the strip member 130 on the interior surface 132 . In one embodiment the attaching member includes a hook.
[0019] In another aspect, the invention is a method of creating hair styles. FIG. 2 shows the hair wrap 100 attached to hair 200 (a pony tail) with the strip member 130 shown in a first extended open position. To get to this position a user grasps a hair wrap 100 and secures hair 200 to the hair wrap 100 by pulling hair through the hair tie 110 . Next, the strip member 130 is articulated into the second generally cylindrical position. FIG. 3 shows the hair wrap 100 attached to hair 200 with the strip member 130 shown in the second cylindrical position to create a pony tail.
[0020] Alternatively, a user may pull their hair 200 through the strip member 130 portion of the hair wrap 100 while in the second generally cylindrical position. FIG. 4 illustrates the pony tail wrap 100 with hair 200 of the pony tail looped back through the hair wrap 100 .
[0021] Though the invention has been described with respect to specific preferred embodiments, many variations and modifications will become apparent to those skilled in the art upon reading the present application. Specifically, the invention may be altered in ways readily apparent to those of ordinary skill in the art upon reading the present disclosure. It is therefore the intention that the appended claims and their equivalents be interpreted as broadly as possible in view of the prior art to include all such variations and modifications.
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The invention is an apparatus and method for creating a hairstyle. 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
[0001] The present application is a continuation-in-part of U.S. application Ser. No. 10/858,100, filed on Jun. 1, 2004, entitled “Method and System to Control Movement of a Body for Nano-Scale Manufacturing,” listing Byung-Jin Choi and Sidlgata V. Sreenivasan as inventors, and a divisional of U.S. application Ser. No. ______ Attorney Docket Number, P228N2271142, filed on even date herewith, entitled “Compliant Device for Nanoscale Manufacturing,” listing Byung-Jin Choi and Sidlgata V. Sreenivasan as inventors.
BACKGROUND OF THE INVENTION
[0002] The field of invention relates generally to orientation devices. More particularly, the present invention is directed to an orientation stage suited for use in imprint lithography and a method of utilizing the same.
[0003] Micro-fabrication involves the fabrication of very small structures, e.g., having features on the order of micro-meters or smaller. One area in which micro-fabrication has had a sizeable impact is in the processing of integrated circuits. As the semiconductor processing industry continues to strive for larger production yields while increasing the circuits per unit area formed on a substrate, micro-fabrication becomes increasingly important. Micro-fabrication provides greater process control while allowing increased reduction of the minimum feature dimension of the structures formed. Other areas of development in which micro-fabrication has been employed include biotechnology, optical technology, mechanical systems and the like.
[0004] An exemplary micro-fabrication technique is commonly referred to as imprint lithography and is described in detail in numerous publications, such as United States published patent applications 2004/0065976, entitled “Method And A Mold To Arrange Features On A Substrate To Replicate Features Having Minimal Dimensional Variability”; 2004/0065252, entitled “Method Of Forming A Layer On A Substrate To Facilitate Fabrication Of Metrology Standards”; 2004/0046271, entitled “Method And A Mold To Arrange Features On A Substrate To Replicate Features Having Minimal Dimensional Variability,” all of which are assigned to the assignee of the present invention. An exemplary imprint lithography technique as shown in each of the aforementioned published patent applications includes formation of a relief pattern in a polymerizable layer and transferring the relief pattern into an underlying substrate, forming a relief image in the substrate. To that end, a template is employed to contact a formable liquid present on the substrate. The liquid is solidified forming a solidified layer that has a pattern recorded therein that is conforming to a shape of the surface of the template. The substrate and the solidified layer are then subjected to processes to transfer, into the substrate, a relief image that corresponds to the pattern in the solidified layer.
[0005] It is desirable to properly align the template with the substrate so that proper orientation between the substrate and the template is obtained. To that end, an orientation stage is typically included with imprint lithography systems. An exemplary orientation device is shown in U.S. Pat. No. 6,696,220 to Bailey et al. The orientation stage facilitates calibrating and orientating the template about the substrate to be imprinted. The orientation stage comprises a top frame and a middle frame with guide shafts having sliders disposed therebetween. A housing having a base plate is coupled to the middle frame, wherein the sliders move about the guide shafts to provide vertical translation of a template coupled to the housing. A plurality of actuators are coupled between the base plate and a flexure ring, wherein the actuators may be controlled such that motion of the flexure ring is achieved, thus allowing for motion of the flexure ring in the vertical direction to control a gap defined between the template and a substrate.
[0006] It is desired, therefore, to provide an improved orientation stage and method of utilizing the same.
SUMMARY OF THE INVENTION
[0007] The present invention is directed towards a method and system of controlling movement of a body coupled to an actuation system that features translating movement of the body in a plane extending by imparting angular motion in the actuation system with respect to two spaced-apart axes. Specifically, rotational motion is generated in two spaced-apart planes, one of which extending parallel to the plane in which the body translates. This facilitates proper orientation of body with respect to a surface spaced-apart therefrom. These and other embodiments are discussed more fully below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an exploded perspective view of an orientation stage showing a template chuck and a template in accordance with the present invention;
[0009] FIG. 2 is perspective view of the orientation stage shown in FIG. 1 ;
[0010] FIG. 3 is an exploded perspective view of a passive compliant device included in the orientation stage shown in FIG. 1 along with the template holder and the template in accordance with a first embodiment of the present invention;
[0011] FIG. 4 is a detailed perspective view of the passive compliant device shown in FIG. 3 ;
[0012] FIG. 5 is a side view of the passive compliant, device shown in FIG. 4 , showing detail of flexure joints included therewith;
[0013] FIG. 6 is a side view of the passive compliant device shown in FIG. 4 ;
[0014] FIG. 7 is a side view of the compliant device, shown in FIG. 6 , rotated 90 degrees;
[0015] FIG. 8 is a side view of the compliant device, shown in FIG. 6 , rotated 180 degrees;
[0016] FIG. 9 is a side view of the compliant device, shown in FIG. 6 , rotated 270 degrees; and
[0017] FIG. 10 is a perspective view of a compliant device in accordance with an alternate embodiment of the present invention;
[0018] FIG. 11 is a simplified elevation view of a the template, shown in FIG. 1 , in superimposition with a substrate showing misalignment along one direction;
[0019] FIG. 12 is a top down view of the template and substrate, shown in FIG. 11 , showing misalignment along two transverse direction;
[0020] FIG. 13 . is a top down view of the template and substrate, shown in FIG. 11 , showing angular misalignment;
[0021] FIG. 14 is a simplified elevation view of the template, shown in FIG. 1 , in superimposition with a substrate showing angular misalignment;
[0022] FIG. 15 is a simplified elevation view showing desired alignment between the template and substrate shown in FIGS. 11, 12 , 13 and 14 ;
[0023] FIG. 16 is a detailed view of one embodiment of the template shown in FIGS. 1, 3 , 11 , 12 , 13 , 14 and 15 in superimposition with a substrate; and
[0024] FIG. 17 is a detailed view of the template shown in FIG. 16 showing a desired spatial arrangement with respect to the substrate.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Referring to FIG. 1 , an orientation stage 10 is shown having an inner frame 12 disposed proximate to an outer frame 14 , a flexure ring 16 and a compliant device 18 . Compliant device 18 is discussed more fully below. The components of orientation stage 10 may be formed from any suitable material, e.g., aluminum, stainless steel and the like and may be coupled together using any suitable means, such as threaded fasteners (not shown). A template chuck 20 is coupled to orientation stage 10 , shown more clearly in FIG. 2 . Specifically, template chuck 20 is coupled to compliant device 18 . Template chuck 20 is configured to support a template 22 , shown in FIG. 1 . An exemplary template chuck is disclosed in United States patent publication No. 2004/0090611 entitled “Chuck System for Modulating Shapes of Substrate,” assigned to the assignee of the present invention and is incorporated by reference herein. Template chuck 20 is coupled to compliant device 18 using any suitable means, such as threaded fasteners (not shown) coupling the four corners of template chuck 20 to the four corners of compliant device 18 position proximate thereto.
[0026] Referring to FIGS. 1 and 2 , inner frame 12 has a central throughway 24 surrounded by a surface 25 , and outer frame 14 has a central opening 26 in superimposition with central throughway 24 . Flexure ring 16 has an annular shape, e.g. circular or elliptical and is coupled to inner frame 12 and outer frame 14 and lies outside of both central throughway 24 and central opening 26 . Specifically, flexure ring 16 is coupled to inner frame 12 at regions 28 , 30 , and 32 and outer frame 14 at regions 34 , 36 , and 38 . Region 34 is disposed between regions 28 and 30 and disposed equidistant therefrom; region 36 is disposed between regions 30 and 32 and disposed equidistant therefrom; and region 38 is disposed between regions 28 and 32 and disposed equidistant therefrom. In this manner, flexure ring 16 surrounds compliant device 18 , template chuck 20 , and template 22 and fixedly attaches inner frame 12 to outer frame 14 . Four corners 27 of compliant device 18 is attached to surface 25 using threaded fasteners (not shown).
[0027] Orientation stage 10 is configured to control movement of template 22 and place the same in a desired spatial relationship with respect to a reference surface (not shown). To that end, plurality of actuators 40 , 42 , and 44 are connected between outer frame 14 and inner frame 12 so as to be spaced about orientation stage 10 . Each of actuators 40 , 42 , and 44 has a first end 46 and a second end 48 . First end 46 of actuator 40 faces outer frame 14 , and second end 48 faces inner frame 12 . Actuators 40 , 42 , and 44 tilt inner frame 12 with respect to outer frame 14 by facilitating translational motion of inner frame 12 along three axes Z 1 , Z 2 , and Z 3 . Orientation stage 10 may provide a range of motion of approximately ±1.2 mm about axes Z 1 , Z 2 , and Z 3 . In this fashion, actuators 40 , 42 , and 44 cause inner frame 12 to impart angular motion to both compliant device 18 and, therefore, template 22 and template chuck 20 , angular motion about one or more of a plurality of axes T 1 , T 2 and T 3 . Specifically, by decreasing a distance between inner frame 12 and outer frame 14 along axes Z 2 and Z 3 and increasing a distance therebetween along axis Z 1 , angular motion about tilt axis T 2 occurs in a first direction. Increasing the distance between inner frame 12 and outer frame 14 along axes Z 2 and Z 3 and decreasing the distance therebetween along axis Z 1 , angular motion about tilt axis T 2 occurs in a second direction opposite to the first direction. In a similar manner angular movement about axis T 1 may occur by varying the distance between inner frame 12 and outer frame 14 by movement of inner frame 12 along axes Z 1 and Z 2 in the same direction and magnitude while moving of the inner frame 12 along axis Z 3 in a direction opposite and twice to the movement along axes Z 1 and Z 2 . Similarly, angular movement about axis T 3 may occur by varying the distance between inner frame 12 and outer frame 14 by movement of inner frame 12 along axes Z 1 and Z 3 in the same direction and magnitude while moving of inner frame 12 along axis Z 2 in direction opposite and twice to the movement along axes Z 1 and Z 3 . Actuators 40 , 42 , and 44 may have a maximum operational force of ±200 N. Orientation stage 10 may provide a range of motion of approximately ±0.15° about axes T 1 , T 2 , and T 3 .
[0028] Actuators 40 , 42 , and 44 are selected to minimize mechanical parts and, therefore, minimize uneven mechanical compliance, as well as friction, which may cause particulates. Examples of actuators 40 , 42 , and 44 include voice coil actuators, piezo actuators, and linear actuators. An exemplary embodiment for actuators 40 , 42 , and 44 is available from BEI Technologies of Sylmar, Calif. under the trade name LA24-20-000A. Additionally, actuators 40 , 42 , and 44 are coupled between inner frame 12 and outer frame 14 so as to be symmetrical disposed thereabout and lie outside of central throughway 24 and central opening 26 . With this configuration an unobstructed throughway between outer frame 14 to compliant device 18 is configured. Additionally, the symmetrical arrangement minimizes dynamic vibration and uneven thermal drift, thereby providing fine-motion correction of inner frame 12 .
[0029] The combination of the inner frame 12 , outer frame 14 , flexure ring 16 and actuators 40 , 42 , and 44 provides angular motion of compliant device 18 and, therefore, template chuck 20 and template 22 about tilt axes T 1 , T 2 and T 3 . It is desired, however, that translational motion be imparted to template 22 along axes that lie in a plane extending transversely, if not orthogonally, to axes Z 1 , Z 2 , and Z 3 . This is achieved by providing compliant device 18 with a functionality to impart angular motion upon template 22 about one or more of a plurality of compliance axes, shown as C 1 and C 2 , which are spaced-part from tilt axes T 1 , T 2 and T 3 and exist on the surface of the template when the template, the template chuck, and the compliant device are assembled.
[0030] Referring to FIGS. 3 and 4 , compliant device 18 includes a support body 50 and a floating body 52 that is coupled to the support body 50 vis-à-vis a plurality of flexure arms 54 , 56 , 58 , and 60 . Template chuck 20 is intended to be mounted to floating body 52 via conventional fastening means, and template 22 is retained by chuck using conventional methods.
[0031] Each of flexure arms 54 , 56 , 58 , and 60 includes first and second sets of flexure joints 62 , 64 , 66 , and 68 . The first and second sets of flexure joints 62 , 64 , 66 , and 68 are discussed with respect to flexure arm 56 for ease of discussion, but this discussion applies equally to the sets of flexure joints associated with flexure arms 56 , 58 , and 60 . Although it is not necessary, compliant device 18 is formed from a solid body, for example, stainless steel. As a result, support body 50 , floating body 52 and flexures arms 54 , 56 , 58 , and 60 are integrally formed and are rotationally coupled together vis-à-vis first and second sets of flexure joints 62 , 64 , 66 , and 68 . Support body 50 includes a centrally disposed throughway 70 . Floating body includes a centrally disposed aperture 72 that is in superimposition with throughway 70 . Each flexure arm 54 , 56 , 58 , and 60 includes opposed ends, 74 and 76 . End 74 of each flexure arms 54 , 56 , 58 , and 60 is connected to support body 50 through flexure joints 66 and 68 . End 74 lies outside of throughway 70 . End 76 of each flexure arm 54 , 56 , 58 , and 60 is connected to floating body 52 through flexure joints 62 and 64 . End 76 lies outside of aperture 72 .
[0032] Referring to FIGS. 4 and 5 , each of joints 62 , 64 , 66 , and 68 are formed by reducing material from device 18 proximate to ends 74 and 76 , i.e., at an interface either of support body 50 or floating body 52 and one of flexure arms 54 , 56 , 58 , and 60 . To that end, flexure joints 62 , 64 , 66 , and 68 are formed by machining, laser cutting or other suitable processing of device 18 . Specifically, joints 64 and 66 are formed from a flexure member 78 having two opposing surfaces 80 and 82 . Each of surfaces 80 and 82 includes hiatus 84 and 86 , respectively. Hiatus 84 is positioned facing away from hiatus 86 , and hiatus 86 faces away from hiatus 84 . Extending from hiatus 86 , away from surface 80 is a gap 88 , terminating in an opening in a periphery of flexure arm 56 . Joints 62 and 68 are also formed from a flexure member 90 having two opposing surfaces 92 and 94 . Each of surfaces 92 and 94 includes a hiatus 96 and 98 , respectively. Hiatus 98 is positioned facing surface 92 , and hiatus 98 faces away from surface 94 . Extending from hiatus 98 , away from surface 92 is a gap 100 , and extending from hiatus 98 is a gap 102 . The spacing S 1 , S 2 and S 3 of gaps 88 , 100 , and 102 , respectively define a range of motion over which relative movement between either of support body 50 and floating body 52 may occur.
[0033] Referring to FIGS. 3 and 5 , flexure member 90 associated with joints 62 of flexure arms 56 and 58 facilitates rotation about axis 104 , and flexure member 78 associated with joints 66 of flexure arms 56 and 58 facilitates rotation about axis 106 . Flexure member 90 associated with joints 62 of flexure arms 54 and 60 facilitates rotation about axis 108 , and flexure member 78 associated with joints 66 of flexure arms 54 and 60 facilitates rotation about axis 110 . Flexure member 78 associated with joints 64 of flexure arms 54 and 56 facilitates rotation about axis 112 , and flexure member 90 associated with joints 68 of flexure arms 54 and 56 facilitates rotation about axis 114 . Flexure member 78 associated with joints 64 of flexure arms 58 and 60 facilitates rotation about axis 116 , and flexure member 90 associated with joints 68 of flexure arms 58 and 60 facilitates rotation about axis 118 .
[0034] As a result, each flexure arm 54 , 56 , 58 , and 60 is located at a region of said device 18 where groups of the axes of rotation overlap. For example, end 74 of flexure arm 54 is located where axes 110 and 114 overlap and end 76 is positioned where axes 108 and 112 overlap. End 74 of flexure arm 56 is located where axes 106 and 114 overlap, and end 76 is positioned where axes 110 and 112 overlap. End 74 of flexure arm 58 is located where axes 106 and 118 overlap, and end 76 is located where axes 104 and 116 overlap. Similarly, end 74 of flexure arm 60 is located where axes 110 and 118 overlap, and end 76 is located where 108 and 116 overlap.
[0035] As a result of this configuration, each flexure arm 54 , 56 , 58 , and 60 is coupled to provide relative rotational movement with respect to support body 50 and floating body 52 about two groups of overlapping axes with a first group extending transversely to the remaining group. This provides each of flexure arms 54 , 56 , 58 , and 60 with movement about two groups of orthogonal axes while minimizing the footprint of the same. Device 18 may provide a tilting motion range of approximately ±0.04°, an active tilting motion range of approximately ±0.02°, and an active theta motion range of approximately ±0.0005° above the above mentioned axes. Furthermore, having the reduced footprint of each flexure arm 54 , 56 , 58 , and 60 allows leaving a void 120 between throughway 70 and aperture 72 unobstructed by flexure arms 54 , 56 , 58 , and 60 . This makes device 18 suited for use with an imprint lithography system, discussed more fully below.
[0036] Referring to FIGS. 4, 6 and 7 , the present configuration of flexure arms 54 , 56 , 58 , and 60 with respect to support body 50 and floating body 52 facilitates parallel transfer of loads in device 18 . For example, were a load force imparted upon support body 50 , each flexures arms 54 , 56 , 58 , and 60 imparts an substantially equal amount of force F 1 upon floating body 52 . Among other things, this facilitates obtaining a desired structural stiffness with device 18 when load with either a force F 1 or a force F 2 . To that end, joints are 62 , 64 , 66 , and 68 are revolute joints which minimize movement, in all directions, between the flexure are and either support body 50 or floating body 52 excepting rotational movement. Specifically, joints 62 , 64 , 66 , and 68 minimize translational movement between flexure arms 54 , 56 , 58 , and 60 , support body 50 and floating body 52 , while facilitating rotational movement about axes 104 , 106 , 108 , 110 , 112 , 114 , 116 , and 118 .
[0037] Referring to FIGS. 4, 5 , 6 , and 7 , the relative position of axes 104 , 106 , 108 , and 110 provides floating body 52 with a first remote center of compliance (RCC) at a position 122 spaced apart from floating body 52 , centered with respect to aperture 72 and equidistant from each axis 104 , 106 , 108 , and 110 . Similarly, the relative position of axes 112 , 114 , 116 , and 118 provides floating body 52 with a second RCC substantially close to position 122 and desirably located at position 122 . Each axis 112 , 114 , 116 , and 118 is positioned equidistant from position 122 . Each axis of the group of axes 104 , 106 , 108 , and 110 extends parallel to the remaining axes 104 , 106 , 108 , and 110 of the group. Similarly, each axis of the group of axes 104 , 106 , 108 , and 110 extends parallel to the remaining axes 104 , 106 , 108 , and 110 of the group and orthogonally to each axis 104 , 106 , 108 , and 110 . Axis 110 is spaced-apart from axis 108 along a first direction a distance d 1 and along a second orthogonal direction a distance d 2 . Axis 104 is spaced-apart from axis 106 along the first direction a distance d 3 and along the second direction a distance d 4 . Axis 112 is spaced-apart from axis 114 along a third direction, that is orthogonal to both the first and second directions a distance d 5 and along the second direction a distance d 6 . Axis 116 is spaced-apart from axis 118 along the second direction a distance d7 and along the third direction a distance d 8 . Distances d 1 , d 4 , d 6 and d 7 are substantially equal. Distances d 2 , d 3 , d 5 and d 8 are substantially equal.
[0038] Two sets of transversely extending axes may be in substantially close proximity such that RCC 122 may be considered to lie upon an intersection thereat by appropriately establishing distances d 1 -d 8 . A first set of includes four axes is shown as 124 , 126 , 128 , and 130 . Joints 62 and 66 of flexure arm 54 lie along axis 124 , and joints 62 and 66 of flexure arm 56 lie along axis 126 . Joints 62 and 66 of flexure arm 58 lie along axis 128 , and joints 62 and 66 of flexure arm 60 lie along axis 130 . A second set of four axes is shown as 132 , 134 , 136 , and 138 . Joints 64 and 68 of flexure arm 56 lie along axis 132 , and joints 64 and 68 of flexure arm 58 lie along axis 134 . Joints 64 and 68 of flexure arm 60 lie along axis 136 , and joints 64 and 68 of flexure arm 54 lie along axis 138 . With this configuration movement of floating body 52 , with respect to RCC 122 , about any one of the set of axes 124 , 126 , 128 , 130 , 132 , 134 , 136 , and 138 is decoupled from movement about the remaining axes 124 , 126 , 128 , 130 , 132 , 134 , 136 , and 138 . This provides a gimbal-like movement of floating body 52 with respect to RCC 122 , with the structural stiffness to resist, if not prevent, translational movement of floating body with respect to axis 124 , 126 , 128 , 130 , 132 , 134 , 136 , and 138 .
[0039] Referring to FIGS. 4 and 10 , in accordance with an alternate embodiment of the present invention, device 18 may be provided with active compliance functionality shown with device 18 . To that end, a plurality of lever arms 140 , 142 , 146 , and 148 are coupled to floating body 52 and extend toward support body 50 terminating proximate to a piston of an actuator. As shown lever arm 140 has one end positioned proximate to the piston of actuator 150 , lever arm 142 has one end positioned proximate to the piston of actuator 152 , lever arm 146 has one end positioned proximate to the piston of actuator 154 and one end of actuator arm 118 is positioned proximate to the piston of actuator 156 that is coupled thereto. By activating the proper sets of actuators 150 , 152 , 154 , and 156 , angular positioning of the relative position of floating body 52 with respect to support body 50 may be achieved. An exemplary embodiment for actuators 150 , 152 , 154 , and 156 is available from BEI Technologies of Sylmar, Calif. under the trade name LA10-12-027A.
[0040] To provide rotational movement of floating body 52 with respect to support body 50 actuators 150 , 152 , 154 , and 156 may be activated. For example, actuator 150 may be activated to move lever arm 140 along the F 1 direction and actuator 154 would be operated to move lever arm 146 in a direction opposite to the direction lever arm 140 moves. Similarly, at least one of actuators 152 and 156 are activated to move lever arms 142 and 148 respectively. Assuming both actuators 152 and 156 are activated, then each of lever arms 140 , 142 , 146 , and 148 are moved toward one of flexure arms 54 , 56 , 58 , and 60 that differs from the flexure arm 54 , 56 , 58 , and 60 toward which the remaining lever arms 140 , 142 , 146 , and 148 move. An example may include moving lever arm 140 toward flexure arm 54 , lever arm 142 toward flexure arm 56 , lever arm 146 toward flexure arm 58 and lever arm 142 toward flexure arm 60 . This would impart rotational movement about the F 3 direction. It should be understood, however, each of lever arms 140 , 142 , 146 , and 148 may be moved in the opposite direction. Were it desired to prevent translational displacement between support body 50 and floating body 52 along the F 3 direction while imparting rotational movement thereabout, then each of lever arms 140 , 142 , 146 , and 148 would be moved the same magnitude. However, were it desired to impart rotational movement of floating body 52 about the F 1 and F 2 directions, this may be achieved in various manners.
[0041] Since rotational movement of floating body 52 is guided by the first and second RCCs, floating body 52 can be actively adjusted for two independent angular configuration with respect to support body by translation along the F 3 direction. For example, moving each of lever arms 140 , 142 , 146 , and 148 with actuators 150 , 152 , 154 , and 156 , respectively, differing amounts would impart translation of floating body 52 along the F 3 direction while imparting angular displacement about the F 3 direction. Additionally, moving only three lever arms 140 , 142 , 146 , and 148 would also impart translation motion about the F 3 direction while imparting angular displacement about the F 3 direction. Were it desired to provide impart translational motion between support body 50 and floating body 52 without impart rotational movement therebetween, two of actuators 150 , 152 , 154 , and 156 would be activated to move two of lever arms 140 , 142 , 146 , and 148 . In one example, two opposing lever arms, such as for example, 140 and 146 , or 142 and 148 would be moved in the same direction the same magnitude. Moving lever arms 140 and 146 in one direction, e.g., toward flexure arms 60 and 58 , respectively, would cause the entire side of floating body 52 extending between flexure arms 58 and 60 to increase in distance from the side of support body 50 in superimposition therewith, effectively creating rotation movement of floating body 16 about the F 2 direction. Decrease would the distance between the side of floating body 52 extending between flexure arms 56 and 54 and the side of support body 50 in superimposition therewith. Conversely, moving lever arms 140 and 146 in an opposite direction, e.g., toward flexure arms 54 and 56 , would cause the entire side of floating body 52 extending between flexure arms 58 and 60 to decrease in distance from the side of support body 50 . The distance between the side of floating body 52 extending between flexure arms 58 and 60 and the side of support body 50 in superimposition therewith would increase. Similarly, rotational movement of floating body 52 about the F 1 direction may be achieved by movement of lever arms 142 and 148 with actuators 152 and 156 , respectively, as discussed above with respect to movement of lever arms 140 and 146 . It should be understood that any linear combination of movement of the aforementioned lever arms may be effectuated to achieve desired motion.
[0042] From the foregoing it is seen that rotational motions of floating body 52 about the F 1 , F 2 and F 3 directions are orthogonal to each other. By adjusting the magnitude of each actuation force or position at actuators 150 , 152 , 154 and 156 , any combination or rotational motions about the F 1 , F 2 and F 3 directions are constrained by the structural stiffness of flexure arms 54 , 56 , 58 , and 60 , floating body 52 and support body 50 .
[0043] Referring to FIGS. 1, 11 and 12 , in operation, orientation stage 10 is typically employed with an imprint lithography system (not shown). An exemplary lithographic system is available under the trade name IMPRIO™ 250 from Molecular Imprints, Inc. having a place of business at 1807-C Braker Lane, Suite 100, Austin, Tex. 78758. The system description for the IMPRIO 100™ is available at www.molecularimprints.com and is incorporated herein by reference. As a result, orientation stage 10 may be employed to facilitate alignment of template 22 with a surface in superimposition therewith, such as a surface of substrate 158 . As a result, the surface of substrate 158 may comprising of the material from which substrate 158 is formed, e.g. silicon with a native oxide present, or may consist of a patterned or unpatterned layer of, for example, conductive material, dielectric material and the like.
[0044] Template 22 and substrate 158 are shown spaced-apart a distance defining a gap 160 therebetween. The volume associated with gap 160 is dependent upon many factors, including the topography of the surface of template 22 facing substrate and the surface of substrate 158 facing template 22 , as well as the angular relationship between a neutral axis A of substrate with respect to the neutral axis B of substrate 158 . In addition, were the topography of both of the aforementioned surfaces patterned, the volume associated with gap 160 would also be dependent upon the angular relation between template 22 and substrate 158 about axis Z. Considering that desirable patterning with imprint lithography techniques is, in large part, dependent upon providing the appropriate volume to gap 160 , it is desirable to accurate align template 22 and substrate 158 . To that end, template 22 includes template alignment marks, one of which is shown as 162 , and substrate 158 includes substrate alignment marks, one of which is shown as 164 .
[0045] In the present example it is assumed that desired alignment between template 22 and substrate 158 occurs upon template alignment mark 162 being in superimposition with substrate alignment mark 164 . As shown, desired alignment between template 22 and substrate 158 has not occurred, shown by the two marks be offset, a distance O. Further, although offset O is shown as being a linear offset in one direction, it should be understood that the offset may be linear along two directions shown as O 1 and O 2 . In addition to, or instead of, the aforementioned linear offset in one or two directions, the offset between template 22 and substrate 158 may also consist of an angular offset, shown in FIG. 13 as angle θ.
[0046] Referring to FIGS. 2, 10 , and 14 , desired alignment between template 22 and substrate 158 is obtained by the combined rotational movement about one or more axes T 1 , T 2 , T 3 , F 1 , F 2 and F 3 . Specifically, to attenuate offset linear offset, movement, as a unit, of compliant device 18 , template chuck 20 and template 22 about one or more axes T 1 , T 2 , T 3 is undertaken. This typically results in an oblique angle φ being produced between neutral axes A and B. Thereafter, angular movement of template 22 about one or more of axes F 1 and F 2 are undertaken to compensate for the angle φ and ensure that neutral axis A extends parallel to neutral axis B. Furthermore, the combined angular movement about axes T 1 , T 2 , T 3 , F 1 , F 2 results in a swinging motion of template 22 to effectuate movement of the same in a plane extending parallel to neutral axis B and transverse, of not orthogonal, to axes Z 1 , Z 2 and Z 3 . In this manner, template 22 may be properly aligned with respect to substrate 158 along to linear axes lying in a plane extending parallel to neutral axis B, shown in FIG. 15 . Were it desired to attenuate, of not abrogate, angular offset, template 22 would be rotated about axis F 3 by use of actuators 150 , 152 , 154 , and 156 to provide the desired alignment.
[0047] After the desired alignment has occurred, actuators 40 , 42 , and 44 are operated to move template 22 into contact with a surface proximate to substrate. In the present example surface consists of polymerizable imprinting material 166 disposed on substrate 158 . It should be noted that actuators 40 , 42 , and 44 are operated to minimize changes in the angle formed between neutral axes A and B once desired alignment has been obtained. It should be known, however, that it is not necessary for neutral axes A and B to extend exactly parallel to one another, so long as the angular deviation from parallelism is within the compliance tolerance of compliant device 18 , as defined by flexure joints 62 , 64 , 66 , and 68 and flexure arms 54 , 56 , 58 , and 60 . In this fashion, neutral axes A and B may be orientated to be as parallel as possible in order to maximize the resolution of pattern formation into polymerizable material. As a result, it is desired that position 122 at which the first and second RCCs are situation be placed at the interface of template 22 and material.
[0048] Referring to FIGS. 1, 16 and 17 , as discussed above, the foregoing system 10 is useful for patterning substrates, such as substrate 158 employing imprint lithography techniques. To that end, template 22 typically includes a mesa 170 having a pattern recorded in a surface thereof, defining a mold 172 . An exemplary template 22 is shown in U.S. Pat. No. 6,696,220, which is incorporated by reference herein. The patterned on mold 172 may comprising of a smooth surface of a plurality of features, as shown, formed by a plurality of spaced-apart recesses 174 and projections 176 . Projections 30 have a width W 1 , and recesses 28 have a width W 2 . The plurality of features defines an original pattern that forms the basis of a pattern to be transferred into a substrate 158 .
[0049] Referring to FIGS. 16 and 17 the pattern recorded in material 166 is produced, in part, by mechanical contact of the material 166 with mold 172 and substrate 158 , which as shown, may include an existing layer thereon, such as a transfer layer 178 . An exemplary embodiment for transfer layer 178 is available from Brewer Science, Inc. of Rolla, Mo. under the trade name DUV30J-6. It should be understood that material 166 and transfer layer 178 may be deposited using any known technique, including drop dispense and spin-coating techniques.
[0050] Upon contact with material 166 , it is desired that portion 180 of material 166 in superimposition with projections 30 remain having a thickness t 1 , and sub-portions 182 remain having a thickness t 2 . Thickness t 1 is referred to as a residual thickness. Thicknesses “t 1 ” and “t 2 ” may be any thickness desired, dependent upon the application. Thickness t 1 and t 2 may have a value in the range of 10 nm to 10 μm. The total volume contained material 166 may be such so as to minimize, or to avoid, a quantity of material 166 from extending beyond the region of substrate 158 not in superimposition with mold 172 , while obtaining desired thicknesses t 1 and t 2 . To that end, mesa 170 is provided with a height, h m , which is substantially greater than a depth of recesses 174 , hr. In this manner, capillary forces of material 166 with substrate 158 and mold 172 restrict movement of material 166 from extending beyond regions of substrate 158 not in superimposition with mold 172 , upon t 1 and t 2 reaching a desired thickness.
[0051] A benefit provided by system 10 is that it facilitates precise control over thicknesses t 1 and t 2 . Specifically, it is desired to have each of thicknesses t 1 be substantially equal and that each of thicknesses t 2 be substantially equal. As shown in FIG. 16 , thicknesses t 1 are not uniform, as neither are thickness t 2 . This is an undesirable orientation of mold 172 with respect to substrate 158 . With the present system 10 , uniform thickness t 1 and t 2 may be obtained, shown in FIG. 17 . As a result, precise control over thickness t 1 and t 2 may be obtained, which is highly desirable. In the present invention, system 10 provide a three sigma alignment accuracy having a minimum feature size of, for example, about 50 nm or less.
[0052] The embodiments of the present invention described above are exemplary. As a result, many changes and modifications may be made to the disclosure recited above, while remaining within the scope of the invention. Therefore, the scope of the invention should not be limited by the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.
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The present invention is directed towards a method and system of controlling movement of a body coupled to an actuation system that features translating movement of the body in a plane extending by imparting angular motion in the actuation system with respect to two spaced-apart axes. Specifically, rotational motion is generated in two spaced-apart planes, one of which extends parallel to the plane in which the body translates. This facilitates proper orientation of the body with respect to a surface spaced-apart therefrom.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an engine control device installed in a vehicle, and more particularly to a crank angle detecting device for an internal combustion engine.
[0003] 2. Description of the Related Art
[0004] A crank angle position detecting means and a cam signal detecting means are used in order to perform engine crank angle position control and cylinder identification. The crank angle position detecting means is generally one that provides a signal every 10° CA (crank angle) in order to perform angle control with excellent accuracy. In addition, devices that perform early stage cylinder identification in order to improve startability have been proposed, and for the case of a four-cylinder engine, cylinder identification is performed at one ignition stroke interval (180° CA).
[0005] A device disclosed in Japanese Patent Laid-Open No. 11-315748, for example, is a conventional internal combustion engine crank angle detecting device.
[0006] The crank angle position detecting means in the device uses a 10° CA signal, and crank angle reference positions (missing teeth) are established in two locations, every 180° CA, in one crank revolution (360° CA period).
[0007] Further, identification signals for from one to four cylinders are established every 180° CA in two crank rotations (720° CA period) as cam signals.
[0008] Crank angle locations are detected by the above-mentioned crank angle detecting means, and cylinder identification is performed with respect to the number of cylinder identification signals in a 180° CA period of the cam signal. The number of cylinder identification signals in the 180° CA period of the cam signal is different for each of the cylinders, and therefore it becomes possible to identify the cylinders every ignition stroke interval. In addition, such a structure is capable of cylinder identification even if the cam phase changes due to a VVT (variable valve timing mechanism).
[0009] For cases in which a different number of cylinder identification signals are established for each cylinder in the cam signal of an engine with VVT, it is necessary to establish cylinder identification signals equal to the number of cylinders during a relatively small angular gap so as to achieve cylinder identification, even if the cam shaft angle changes by VVT, with a conventional device as discussed above. The gap between signals becomes small if the diameter of a cam signal vane is small, and therefore there is a problem in that the cylinder identification signal cannot be detected by the cam signal detecting means.
[0010] Further, the number of cylinder identification signals of the cam signal increases if there are additional cylinders, so that the signal gap becomes increasingly short, and there is a problem in that detection of the cylinder identification signal cannot be made by the cam signal detecting means.
SUMMARY OF THE INVENTION
[0011] The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to obtain an crank angle detecting device for an internal combustion engine capable of simplifying information that must be established in cam signal vanes in order to perform cylinder identification by establishing a cylinder group identifying means (missing tooth) in the crank signal vane.
[0012] A crank angle detecting device for an internal combustion engine according to an aspect of the present invention includes: a crank signal vane that rotates in synchronous with a crank shaft of the internal combustion engine, and is provided with teeth on a circumference at predetermined crank angles, and with a first missing tooth portion having a first predetermined number of missing teeth and a second missing tooth portion having a second predetermined number of missing teeth. Also, the crank angle detecting device includes: a crank angle sensor that outputs a pulse shape crank signal pattern corresponding to the teeth and attached in proximity to the crank signal vane; and an electronic control unit that calculates a crank signal period based on the crank signal pattern, computes a missing teeth determination value based on the calculated crank signal period, detects the number of missing teeth based on the computed missing teeth determination value, and detects a crank angle reference position based on the detected number of missing teeth. As a result, there can be obtained such an effect that the crank angle can be computed.
[0013] A crank angle detecting device for an internal combustion engine according to another aspect of the present invention includes: a crank signal vane that rotates in synchronous with a crank shaft of the internal combustion engine, and is provided with teeth on a circumference at predetermined crank angles, and with a first missing tooth portion having a first predetermined number of missing teeth and a second missing tooth portion having a second predetermined number of missing teeth. Also the crank angle detecting device includes a crank angle sensor that outputs a pulse shape crank signal pattern corresponding to the teeth and attached in proximity to the crank signal vane; and an electronic control unit having: a determination value computing means for calculating a crank signal period based on the crank signal pattern and computes a missing teeth determination value based on the calculated crank signal period; a region determining means for determining which of the missing tooth regions that are set in advance corresponds to the missing teeth determination value; and a missing teeth number identifying means for comparing a plurality of region determination values that are obtained in a time sequence from the region determining means with a predetermined discrimination pattern, which detects a crank angle reference position based on the determined number of missing teeth. As a result, there can be obtained such an effect that the amount of leeway is increased for missing tooth detection.
[0014] A crank angle detecting device for an internal combustion engine according to another aspect of the present invention includes: a crank signal vane that rotates in synchronous with a crank shaft of the internal combustion engine, and is provided with teeth on a circumference at predetermined crank angles, in which a plurality of missing tooth portions are formed, and at least the number of teeth existing between a reference missing tooth portion and at least one adjacent missing tooth portion differs from the number of teeth existing between other missing tooth portions. Also, the crank angle detecting device includes a crank angle sensor that outputs a pulse shape crank signal pattern corresponding to the teeth and attached in proximity to the crank signal vane; and an electronic control unit that finds the number of teeth between the missing tooth portions based on the crank signal pattern, and detects a reference position of the crank angle. As a result, there can be obtained such an effect that the crank angle can be computed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In the accompanying drawings:
[0016] [0016]FIG. 1 is a diagram showing the structure of a crank angle detecting device for an internal combustion engine according to Embodiment 1 of the present invention;
[0017] [0017]FIG. 2 is a diagram showing a crank signal vane of a four-cylinder engine according to Embodiment 1 of the present invention;
[0018] [0018]FIG. 3 is a diagram showing a crank signal pattern of the four-cylinder engine according to Embodiment 1 of the present invention;
[0019] [0019]FIG. 4 is a flowchart showing action of a crank angle detecting device for the internal combustion engine according to Embodiment 1 of the present invention;
[0020] [0020]FIG. 5 is a flowchart showing action of a crank angle detecting device for an internal combustion engine according to Embodiment 2 of the present invention;
[0021] [0021]FIG. 6 is a diagram showing a missing tooth region during missing teeth number identification by a crank angle detecting device for the internal combustion engine according to Embodiment 2 of the present invention;
[0022] [0022]FIG. 7 is a diagram showing a missing teeth number identification map of a four-cylinder engine according to Embodiment 2 of the present invention;
[0023] [0023]FIG. 8 is a diagram showing a crank signal vane of a six-cylinder engine according to Embodiment 3 of the present invention;
[0024] [0024]FIG. 9 is a diagram showing a crank signal pattern of the six-cylinder engine according to Embodiment 3 of the present invention;
[0025] [0025]FIG. 10 is a diagram showing a missing teeth number identification map of a six-cylinder engine according to Embodiment 4 of the present invention;
[0026] [0026]FIG. 11 is a diagram showing a crank signal pattern of a six-cylinder engine according to another example of Embodiment 4 of the present invention;
[0027] [0027]FIG. 12 is a diagram showing a crank signal vane of a three-cylinder engine according to Embodiment 5 of the present invention;
[0028] [0028]FIG. 13 is a diagram showing a crank signal pattern of the three-cylinder engine according to Embodiment 5 of the present invention;
[0029] [0029]FIG. 14 is a diagram showing a crank signal pattern of a three-cylinder engine according to another example of Embodiment 6 of the present invention;
[0030] [0030]FIG. 15 is a diagram showing a crank signal pattern of a four-cylinder engine according to Embodiment 7 of the present invention;
[0031] [0031]FIG. 16 is a flowchart showing action of a crank angle detecting device for an internal combustion engine according to Embodiment 7 of the present invention;
[0032] [0032]FIG. 17 is a diagram showing a crank signal pattern of a six-cylinder engine according to Embodiment 8 of the present invention; and
[0033] [0033]FIG. 18 is a diagram showing a crank signal pattern of a three-cylinder engine according to another example of Embodiment 8 of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Embodiment 1 explains a method of detecting the number of missing teeth with respect to the range of a missing tooth identification value K of a four-cylinder engine, and Embodiment 2 similarly explains a method of determining the number of missing teeth by using a missing teeth number identification map for a four-cylinder engine.
[0035] Further, Embodiment 3 explains a method of detecting the number of missing teeth with respect to the range of a missing tooth identification value K of a six-cylinder engine, and Embodiment 4 similarly explains a method of determining the number of missing teeth by using a missing teeth number identification map for a six-cylinder engine.
[0036] Further, Embodiment 5 explains a method of detecting the number of missing teeth with respect to the range of a missing tooth identification value K of a three-cylinder engine, and Embodiment 6 similarly explains a method of determining the number of missing teeth by using a missing teeth number identification map for a three-cylinder engine.
[0037] In addition, Embodiment 7 explains a method of detecting the number of missing teeth with respect to the range of the missing tooth identification value K of a four-cylinder engine for cases in which missing teeth are set in two locations in each ignition stroke interval, and Embodiment 8 explains a method of detecting the number of missing teeth with respect to the range of the missing tooth identification value K of a six-cylinder engine and a three-cylinder engine for cases in which missing teeth are set in two locations in each ignition stroke interval.
[0038] Embodiment 1
[0039] A crank angle detecting device for an internal combustion engine according to Embodiment 1 of the present invention is explained while referring to the diagrams. FIG. 1 is a diagram showing the schematic structure of the internal combustion engine according to Embodiment 1 of the present invention. Note that, within each of the figures, identical reference numerals denote identical or corresponding portions.
[0040] In FIG. 1, reference numeral 1 denotes an internal combustion engine, reference numeral 2 denotes an air cleaner, reference numeral 3 denotes an air flow sensor, reference numeral 4 denotes an intake pipe, reference numeral 5 denotes a throttle valve, reference numeral 6 denotes an injector, reference numeral 7 denotes an exhaust pipe, and reference numeral 8 denotes an oxygen (O 2 ) sensor. Reference numeral 9 denotes a catalyst, reference numeral 10 denotes an ignition coil, reference numeral 11 denotes a spark plug, reference numeral 12 denotes a cam signal sensor, and reference numeral 13 denotes a cam signal vane. Reference numeral 14 denotes a cam shaft, reference numeral 15 denotes a crank angle sensor, reference numeral 16 denotes a crank signal vane, reference numeral 17 denotes a crank shaft, and reference numeral 18 denotes an electronic control unit (ECU). Note that FIG. 1 can also be considered for the explanations of four-cylinder, six-cylinder, and three-cylinder engines in each of the following embodiments.
[0041] [0041]FIG. 2 is a diagram showing a crank signal vane of a four-cylinder engine according to Embodiment 1 of the present invention.
[0042] Teeth (protrusions) are formed in the crank signal vane 16 at every 10° CA in 360° of CA. Further, a 20° CA missing teeth portion (one missing tooth), and a 30° missing teeth portion (two missing teeth) are formed each 180° of CA.
[0043] Actions of the crank angle detecting device for the internal combustion engine according to Embodiment 1 are explained next while referring to the diagrams.
[0044] [0044]FIG. 3 is a diagram showing a crank signal pattern of the four-cylinder engine according to Embodiment 1 of the present invention.
[0045] The crank signal pattern shown in FIG. 3 is detected by the crank angle sensor 15 , and is input to the electronic control unit 18 . The crank signal pattern is a signal output waveform of the crank angle sensor 15 with respect to the teeth of the crank signal vane 16 shown in FIG. 2.
[0046] The electronic control unit 18 is set so as to detect the trailing edge timing of the crank signal, and perform computation processing for each training edge.
[0047] The electronic control unit 18 performs computation of the missing tooth identification value K described below for each crank signal detection, and detection of the number of missing teeth is performed with respect to the range of the missing tooth identification value K.
K =( Tn− 1){circumflex over ( )}2/{( Tn− 2)* Tn}
[0048] Tn expresses the current crank signal period, Tn−1 expresses the previous crank signal period, and Tn−2 expresses the crank signal period before the previous crank signal period.
[0049] If K<2.25, then no missing teeth are detected. Further, if 2.25≦K<6.25, then one missing tooth is detected. In addition, if K≧6.25, then two missing teeth are detected.
[0050] A method of missing teeth detection is explained according to FIG. 3. Note that the term crank signal period as used here simply denotes the ratio of angular gaps.
[0051] If the crank signal detected this time is equal to 1 to 6, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K=1 2 ÷(1×1)=1. This corresponds to a case in which K<2.25, and therefore no missing teeth are detected.
[0052] If the crank signal detected this time is equal to 7, then Tn−2=1, Tn−1=1, and Tn=3, and therefore K=1 2 ÷(1×3)=0.33. This corresponds to a case in which K<2.25, and therefore no missing teeth are detected.
[0053] If the crank signal detected this time is equal to 8, then Tn−2=1, Tn−1=3, and Tn=1, and therefore K=3 2 ÷(1×1)=9. This corresponds to a case in which K≧6.25, and therefore two missing teeth are detected.
[0054] Two missing teeth detection is performed with a crank signal being in the position of 8, and therefore the angular position is detected as B 75 ° CA (75° CA before top dead center) and the cylinder group is detected as A.
[0055] Similarly, if the crank signal detected this time is equal to 25, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷(1×1)=4. This corresponds to a case in which 2.25≦K<6.25, and therefore one missing tooth is detected.
[0056] One missing tooth detection is performed with a crank signal of 25, and therefore the angular position is detected as B 75 ° CA and the cylinder group is detected as B.
[0057] [0057]FIG. 4 is a flowchart showing action of the crank angle detecting device for the internal combustion engine according to Embodiment 1 of the present invention.
[0058] First, the electronic control unit 18 calculates a crank signal period in a step 101 .
[0059] That is, the crank signal period Tn of this time is calculated as follows.
Tn =(current crank signal detection time)−(previous crank signal detection time)
[0060] The missing tooth identification value is computed next from the crank signal period in a stop 102 .
[0061] That is, the missing tooth identification value K is computed as follows.
K =(previous crank signal period) 2 /{(crank signal period before previous crank signal period)*(current crank signal period)}
[0062] Identification of the number of missing teeth is performed next in a step 103 . If the missing tooth identification value K<2.25, it is determined that there are no missing teeth. Further, if 2.25≦K<6.25, then one missing tooth is detected. In addition, if K≧6.25, then two missing teeth are detected.
[0063] For cases in which missing teeth are thus identified, the crank angle reference position (B 75 ° CA) is found, and cylinder group identification can be performed with respect to the number of missing teeth detected.
[0064] In Embodiment 1, the crank angle and the cylinder groups A and B can be identified with respect to the crank signal. That is, in a four-cylinder engine, cylinder identification can be performed by providing two types of information (cylinder identification signals) to the cam signal vane, and therefore the cam signal vane information can be simplified.
[0065] Embodiment 2
[0066] A crank angle detecting device for an internal combustion engine according to Embodiment 2 of the present invention is explained while referring to the diagrams. The structure of the crank angle detecting device for the internal combustion engine according to Embodiment 2 of the present invention is similar to that of Embodiment 1 above.
[0067] The electronic control unit 18 performs computation of the identification expressions described below for each crank signal detection, and detection of the number of missing teeth is performed with respect to the range of the identification value.
K 1=( Tn− 1)/( Tn− 2)
K 2=( Tn− 1)/ Tn
K =( K 1 +K 2)/2
[0068] Tn expresses the current crank signal period, Tn−1 expresses the previous crank signal period, and Tn−2 expresses the crank signal period before the previous crank signal period.
[0069] A method of missing teeth detection is explained according to FIG. 3. Note that the term crank signal period as used here simply denotes the ratio of angular gaps.
[0070] [0070]FIG. 6 is a diagram showing a missing tooth region during identification of the number of missing teeth on a four-cylinder engine. Further, FIG. 7 is a diagram showing a number of missing teeth map for the four-cylinder engine.
[0071] In FIG. 7, reference symbols “D/E”, “A/B”, “B/C/D” denotes three types of region reference values, and in addition, the two region reference values “A/B” and “B/C/D” show a duplication of a “B” region. The amount of detection leeway, in particular, is increased by using this type of structure, and even with sudden angular speed variations of the engine and the like, the reliability of missing tooth identification is increased considerably. Note that FIG. 10 is also similar.
[0072] Further, a “1 missing tooth” pattern and a “two missing teeth” pattern in FIG. 7 are used for elements that identify differences in the number of teeth existing between missing tooth, that is “n−1 to n−16=16 teeth”, and “n−1 to n−15=15 teeth”. The accuracy and reliability of missing tooth identification can be increased considerably by using this type of structure. Note that FIG. 10 is also similar.
[0073] The correspondence between the missing tooth identification value K and missing tooth regions A, B, C, D, and E is as follows. The missing tooth region is A if K<1.5. Further, if 1.5≦K<2, then the missing tooth region is B. Further, if 2≦K<2.5, then the missing tooth region is C, and if 2.5≦K<3, then the missing tooth region is D. In addition, the missing tooth region is E if K≧3.
[0074] If the crank signal detected this time is equal to 1 to 6, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K1=1/1=1, K2=1/1=1, and K=(1+1)/2=1. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0075] If the crank signal detected this time is equal to 7, then Tn−2=1, Tn−1=1, and Tn=3, and therefore K1=1/1=1, K2=1/3=0.33, and K=(1+0.33)/2=0.67. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0076] If the crank signal detected this time is equal to 8, then Tn−2=1, Tn−1=3, and Tn=1, and therefore K1=3/1=3, K2=3/1=3, and K=(3+3)/2=3. This corresponds to a case in which K≧3, and therefore the missing tooth region E is detected.
[0077] In Embodiment 1 above, detection of two missing teeth is made when the crank signal is in the position of 8, but in Embodiment 2, missing tooth detection is implemented using the missing teeth number identification map (discrimination pattern) of FIG. 7 for cases in which the distribution region of the missing tooth region detected (region identification value) coincides with the missing teeth number identification map. If the missing tooth region identified this time is taken as n, then it is distributed at this point in the missing tooth region A when the crank signal is from n−7 to n−1, and is distributed in the missing tooth region E when the crank signal is equal to n. However, identification is not performed for regions having a number that satisfies the map, and therefore missing tooth detection is not implemented.
[0078] Similarly, if the crank signal detected this time is equal to 9, then Tn−2=3, Tn−1=1, and Tn=1, and therefore K1=1/3=0.33, K2=1/1=1, and K=(0.33+1)/2=0.67. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0079] If the crank signal detected this time is equal to 10 to 23, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K1=1/1=1, K2=1/1=1, and K=(1+1)/2=1. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0080] If the crank signal detected this time is equal to 24, then Tn−2=1, Tn−1=1, and Tn=2, and therefore K1=1/1=1, K2=1/2=0.5, and K=(1+0.5)/2=0.75. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0081] With crank signal positions from 16 to 24, the number of the previously identified missing tooth region is equal to or greater than 16, and therefore identification of the region of the number satisfying the map is performed. However, all the regions are the missing tooth region A, and therefore the distribution range of the missing tooth region (region identification value) coincides with the third missing teeth number identification map (discrimination pattern), and the number of missing teeth is identified as “none”.
[0082] If the crank signal detected this time is equal to 25 , then Tn−2=1, Tn−1=2, and Tn=1, and therefore K1=2/1=2, K2=2/1=2, and K=(2+2)/2=2. This corresponds to a case in which 2≦K<2.5, and therefore the missing tooth region C is detected.
[0083] If the crank signal is n−17 here, it is distributed in the missing tooth region E, and if the crank signal is from n−16 to n−1, it is distributed in the missing tooth region A. The distribution range of the missing tooth region (region identification value) therefore coincides with the first missing teeth number identification map (discrimination pattern), and the number of missing teeth is identified as “1”.
[0084] One missing tooth detection is performed with a crank signal of 25, and therefore the angular position is detected as B 75 ° CA and the cylinder group is detected as B.
[0085] Two missing teeth detection is not performed with the initial crank signal of 8, but with the next crank signal of 8, identification of the region of the number that satisfies the above-mentioned map is performed. If the crank signal is n−16, it is distributed in the missing tooth region C, and if the crank signal is from n−15 to n−1, it is distributed in the missing tooth region A. When the crank signal is n, it is distributed in the missing tooth region E. The distribution range of the missing tooth region (region identification value) therefore coincides with the second missing teeth number identification map (discrimination pattern), and the number of missing teeth is identified as “2”.
[0086] Two missing teeth detection is performed with the next crank signal of 8, and therefore the angular position is detected as B 75 ° CA and the cylinder group is detected as A.
[0087] In order to detect zero missing teeth, one missing tooth, and two missing teeth in Embodiment 1 above, threshold values are respectively set for classification, and detection of the number of missing teeth is performed. It is possible to set each of the classification threshold values for cases in which there is little variation in the crank signal period, but if there are large variations in the crank signal period, such as during startup, it is difficult to set the respective classification threshold values, and cases of erroneous detection of the number of missing teeth occur.
[0088] The number of missing teeth is not simply classified by threshold values in Embodiment 2, but rather, a plurality of missing teeth regions corresponding to each missing tooth are set, and the number of missing teeth is detected with respect to the distribution range of the missing tooth region (region identification value), and therefore breadth of each missing tooth threshold value becomes larger, and missing tooth detection can be performed with good accuracy even for cases in which variations in the crank signal period are large.
[0089] [0089]FIG. 5 is a flow chart showing action of the crank angle detecting device for the internal combustion engine according to Embodiment 2 of the present invention.
[0090] A method of performing identification of the missing teeth number with respect to the missing tooth identification value K is explained in Embodiment 1 above, but the number of missing teeth is detected in Embodiment 2 by a method like that discussed above in order to increase the amount of leeway for detecting the number of missing teeth. This computation processing method of Embodiment 2 is explained based on FIG. 5.
[0091] First, the electronic control unit 18 calculates a crank signal period in a step 201 .
[0092] That is, the crank signal period Tn of this time is calculated as follows.
Tn =(current crank signal detection time)−(previous crank signal detection time)
[0093] Next, a missing tooth region is identified in a step 202 for each of the crank signal periods detected. Crank signal period ratios (Tn−1)/(Tn−2) and (Tn−1)/Tn are found first, and identification of the missing teeth regions A to E is performed when a horizontal axis shown in FIG. 6 is (previous crank signal period)/(crank signal period before previous crank signal period) and a vertical axis shown in FIG. 6 is (previous crank signal period)/(current crank signal period).
[0094] Identification of the number of missing teeth is performed next in a step 203 based on the missing tooth region. For cases in which a time sequence (region identification values) of missing tooth regions identified above coincides with a missing teeth number identification map (discrimination pattern) describing a time sequence of a missing tooth region corresponding to the number of missing teeth based on FIG. 7, the number of missing teeth is identified.
[0095] For example, refer to FIG. 3. For cases in which the crank signal period ratios corresponding to 18 successive crank signals (n−17 to n) are distributed in successive corresponding missing tooth regions, the electronic control unit 18 identifies the corresponding number of missing teeth.
[0096] That is, for cases in which the above crank signal period ratio is distributed in the missing tooth region B, C, or D shown in FIG. 6 when the currently detected crank signal is n, the crank signal period ratio is distributed in the missing tooth region A or B when the crank signal is from n−1 to n−16, and the crank signal period ratio is distributed in the missing tooth region D or E when the crank signal is n−17, the electronic control unit 18 identifies one missing tooth.
[0097] Each of the permitted regions of existence for the missing teeth becomes larger when identifying the number of missing teeth as in Embodiment 2, compared to classifying the number of missing teeth by threshold values as in Embodiment 1, and therefore the degree of leeway for detection increases.
[0098] The numbers of missing teeth are one and two in Embodiment 2, but the numbers of missing teeth are not limited to those. For example, the numbers of missing teeth may also be two and three. In this case the difference with respect to no missing teeth becomes very clear, and therefore the influence of periodic variations due to engine rotation variations becomes small, and missing tooth identification becomes easy.
[0099] Embodiment 3
[0100] A crank angle detecting device for an internal combustion engine according to Embodiment 3 of the present invention is explained while referring to the diagrams.
[0101] [0101]FIG. 8 is a diagram showing a crank signal vane of a six-cylinder engine according to Embodiment 3 of the present invention.
[0102] Teeth (protrusions) are formed in the crank signal vane 16 at every 10° CA in 360° of CA. Further, two 20° CA missing teeth portions (one missing tooth), and one 30° CA missing teeth portion (two missing teeth) are formed each 120° of CA.
[0103] Actions of the crank angle detecting device for the internal combustion engine according to Embodiment 3 are explained next while referring to the diagrams.
[0104] [0104]FIG. 9 is a diagram showing a crank signal pattern of the six-cylinder engine according to Embodiment 3 of the present invention.
[0105] The crank signal pattern shown in FIG. 9 is detected by the crank angle sensor 15 , and is input to the electronic control unit 18 . The crank signal pattern is a signal output waveform of the crank angle sensor 15 with respect to the teeth of the crank signal vane 16 shown in FIG. 8.
[0106] The electronic control unit 18 is set so as to detect the trailing edge timing of the crank signal, and perform computation processing for each training edge.
[0107] The electronic control unit 18 performs computation of the missing tooth identification value K described below for each crank signal detection similarly to Embodiment 1 above, and detection of the number of missing teeth is performed with respect to the range of the missing tooth identification value K.
K =( Tn− 1){circumflex over ( )}2/{( Tn− 2)* Tn}
[0108] Tn expresses the current crank signal period, Tn−1 expresses the previous crank signal period, and Tn−2 expresses the crank signal period before the previous crank signal period.
[0109] If K<2.25, then no missing teeth are detected. Further, if 2.25≦K<6.25, then one missing tooth is detected. In addition, if K≧6.25, then two missing teeth are detected.
[0110] A method of missing teeth detection is explained according to FIG. 9. Note that the term crank signal period as used here simply denotes the ratio of angular gaps.
[0111] If the crank signal detected this time is equal to 1 to 4, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K=1 2 ÷(1×1)=1. This corresponds to a case in which K<2.25, and therefore no missing teeth are detected.
[0112] If the crank signal detected this time is equal to 5, then Tn−2=1, Tn-I=1, and Tn=3, and therefore K=1 2 ÷(1×3)=0.33. This corresponds to a case in which K<2.25, and therefore no missing teeth are detected.
[0113] If the crank signal detected this time is equal to 6, then Tn−2=1, Tn−1=3, and Tn=1, and therefore K=3 2 ÷(1×1)=9. This corresponds to a case in which K>6.25, and therefore two missing teeth are detected.
[0114] Two missing teeth detection is performed with a crank signal of 6, and therefore the angular position is detected as B 75 ° CA (75° CA before top dead center) and the cylinder group is detected as A.
[0115] Similarly, if the crank signal detected this time is equal to 17, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷(1×1)=4. This corresponds to a case in which 2.25≦K<6.25, and therefore one missing tooth is detected.
[0116] One missing tooth detection is performed with a crank signal of 17, and therefore the angular position is detected as B 75 ° CA and the cylinder group is detected as B.
[0117] Similarly, if the crank signal detected this time is equal to 28, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷(1×1)=4. This corresponds to a case in which 2.25≦K<6.25, and therefore one missing tooth is detected.
[0118] One missing tooth detection is performed with a crank signal of 28, and therefore the angular position is detected as B 75 ° CA and the cylinder group is detected as B.
[0119] The angular gaps for the missing teeth include two locations of 20° CA, and one location of 30° CA, with the crank signal vane 16 shown in FIG. 8, and therefore the identified crank angle reference positions become one at B 75 ° CA (A) and two at B 75 ° CA (B).
[0120] In Embodiment 3, the crank angle and the cylinder groups A and B can be identified with respect to the crank signal. That is, in a six-cylinder engine, cylinder identification can be performed by providing four types of information (cylinder identification signals) to the cam signal vane, and therefore the cam signal vane information can be simplified.
[0121] Embodiment 4
[0122] A crank angle detecting device for an internal combustion engine according to Embodiment 4 of the present invention is explained while referring to the diagrams.
[0123] Embodiment 4 utilizes the missing teeth region and the missing teeth number identification map of Embodiment 2 above to identify the number of missing teeth.
[0124] [0124]FIG. 10 is a diagram showing a missing teeth number identification map of a six-cylinder engine. The number of missing teeth for cases in which a series of missing tooth regions of a time sequence (region identification values) matches the missing tooth identification map (discrimination pattern) is identified based on FIG. 10, similar to Embodiment 2 above.
[0125] The electronic control unit 18 performs computation of the identification expressions described below for each crank signal detection, and detection of the number of missing teeth is performed with respect to the range of the identification value.
K 1=( Tn− 1)/( Tn− 2)
K 2=( Tn− 1)/ Tn
K =( K 1 +K 2)/2
[0126] Tn expresses the current crank signal period, Tn−1 expresses the previous crank signal period, and Tn−2 expresses the crank signal period before the previous crank signal period.
[0127] A method of missing teeth detection is explained according to FIG. 9. Note that the term crank signal period as used here simply denotes the ratio of angular gaps.
[0128] The correspondence between the missing tooth identification value K and missing tooth regions A, B, C, D, and E is as follows. The missing tooth region is A if K<1.5. Further, if 1.5≦K<2, then the missing tooth region is B. Further, if 2≦K<2.5, then the missing tooth region is C, and if 2.5≦K<3, then the missing tooth region is D. In addition, the missing tooth region is E if K≧3.
[0129] If the crank signal detected this time is equal to 1 to 4, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K1=1/1=1, K2=1/1=1, and K=(1+1)/2=1. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0130] If the crank signal detected this time is equal to 5, then Tn−2=1, Tn−1=1, and Tn=3, and therefore K1=1/1=1, K2=1/3=0.33, and K=(1+0.33)/2=0.67. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0131] If the crank signal detected this time is equal to 6, then Tn−2=1, Tn−1=3, and Tn=1, and therefore K1=3/1=3, K2=3/1=3, and K=(3+3)/2=3. This corresponds to a case in which K≧3, and therefore the missing tooth region E is detected.
[0132] In Embodiment 3 above, detection of two missing teeth is made when the crank signal is in the position of 6, but in Embodiment 4, missing tooth detection is implemented using the missing teeth number identification map (discrimination pattern) of FIG. 10 for cases in which the distribution region of the missing tooth region detected (region identification value) coincides with the missing teeth number identification map. If the missing tooth region identified this time is taken as n, then it is distributed at this point in the missing tooth region A when the crank signal is from n−7 to n−1, and is distributed in the missing tooth region E when the crank signal is equal to n. However, identification is not performed for regions having a number that satisfies the map, and therefore missing tooth detection is not implemented.
[0133] Similarly, if the crank signal detected this time is equal to 7, then Tn−2=3, Tn−1=1, and Tn=1, and therefore K1=1/3=0.33, K2=1/1=1, and K=(0.33+1)/2=0.67. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0134] If the crank signal detected this time is equal to 8 to 15, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K1=1/1=1, K2=1/1=1, and K=(1+1)/2=1. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0135] If the crank signal detected this time is equal to 16, then Tn−2=1, Tn−1=1, and Tn=2, and therefore K1=1/1=1, K2=1/2=0.5, and K=(1+0.5)/2=0.75. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0136] With crank signal positions from 10 to 16, the previously identified missing tooth region is equal to or greater than 10, and therefore identification of the region of the number satisfying the map is performed. However, all the regions are the missing tooth region A, and therefore the distribution range of the missing tooth region (region identification value) coincides with the third missing teeth number identification map (discrimination pattern), and the number of missing teeth is identified as “none”.
[0137] If the crank signal detected this time is equal to 17, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K1=2/1=2, K2=2/1=2, and K=(2+2)/2=2. This corresponds to a case in which 2≦K<2.5, and therefore the missing tooth region C is detected.
[0138] If the crank signal is n−11 here, it is distributed in the missing tooth region E, if the crank signal is from n−10 to n−1, it is distributed in the missing tooth region A, and if the crank signal is n, it is distributed in the missing tooth region C. The distribution range of the missing tooth region (region identification value) therefore coincides with the first missing teeth number identification map (discrimination pattern), and the number of missing teeth is identified as “1”.
[0139] One missing tooth detection is performed with a crank signal of 17, and therefore the angular position is detected as B 75 ° CA and the cylinder group is detected as B.
[0140] Similarly, if the crank signal detected this time is equal to 28, then Tn−2=1, Tn−1=2, and Tn 1 , and therefore K1=2/1=2, K2=2/1=2, and K=(2+2)/2=2. This corresponds to a case in which 2≦K<2.5, and therefore the missing tooth region C is detected.
[0141] If the crank signal is n−11 here, it is distributed in the missing tooth region E, if the crank signal is from n−10 to n−1, it is distributed in the missing tooth region A, and if the crank signal is n, it is distributed in the missing tooth region C. The distribution range of the missing tooth region (region identification value) therefore coincides with the first missing teeth number identification map (discrimination pattern), and the number of missing teeth is identified as “1”.
[0142] One missing tooth detection is performed with a crank signal of 28, and therefore the angular position is detected as B 75 ° CA and the cylinder group is detected as B.
[0143] Two missing teeth detection is not performed with the initial crank signal of 6, but with the next crank signal of 6, identification of the region of the number that satisfies the above-mentioned map is performed. If the crank signal is n−10, it is distributed in the missing tooth region C, and if the crank signal is from n−9 to n−1, it is distributed in the missing tooth region A. When the crank signal is n, it is distributed in the missing tooth region E. The distribution range of the missing tooth region (region identification value) therefore coincides with the second missing teeth number identification map (discrimination pattern), and the number of missing teeth is identified as “2”.
[0144] Two missing teeth detection is performed with the next crank signal of 6, and therefore the angular position is detected as B 75 ° CA and the cylinder group is detected as A.
[0145] In order to detect zero missing teeth, one missing tooth, and two missing teeth in Embodiment 3 above, threshold values are respectively set for classification, and detection of the number of missing teeth is performed. It is possible to set each of the classification threshold values for cases in which there is little variation in the crank signal period, but if there are large variations in the crank signal period, such as during startup, it is difficult to set the respective classification threshold values, and cases of erroneous detection of the number of missing teeth occur.
[0146] The number of missing teeth is not simply classified by threshold values in Embodiment 4, but rather, a plurality of missing teeth regions corresponding to each missing tooth are set, and the number of missing teeth is detected with respect to the distribution range of the missing tooth region (region identification value), and therefore breadth of each missing tooth threshold value becomes larger, and missing tooth detection can be performed with good accuracy even for cases in which variations in the crank signal period are large.
[0147] The angular gaps between missing teeth of the crank signal vane 16 include one location of 30° CA, and two locations of 20° CA in this example, but the angular gap between missing teeth may also be changed per missing tooth as shown in FIG. 11 as another example.
[0148] There are two locations of 20° CA in FIG. 9, and therefore the crank angle reference position B 75 ° CA (B) can only be identified as one of the two locations, but by changing the angular gaps of all of the missing teeth as in FIG. 11, a specific crank angle reference position B 75 ° CA can be detected.
[0149] As another example of Embodiment 4, the crank angle and the cylinder groups A, B, and C can be identified with respect to the crank signal. That is, in a six-cylinder engine, cylinder identification can be performed by providing two types of information (cylinder identification signals) to the cam signal vane, and therefore the cam signal vane information can be simplified.
[0150] Embodiment 5
[0151] A crank angle detecting device for an internal combustion engine according to Embodiment 5 of the present invention is explained while referring to the diagrams.
[0152] [0152]FIG. 12 is a diagram showing a crank signal vane of a three-cylinder engine according to Embodiment 5 of the present invention.
[0153] Teeth (protrusions) are formed in the crank signal vane 16 at every 10° CA in 360° of CA. Further, two 20° CA missing teeth portions (one missing tooth), and one 30° CA missing teeth portion (two missing teeth) are formed each 120° of CA.
[0154] Actions of the crank angle detecting device for the internal combustion engine according to Embodiment 5 are explained next while referring to the diagrams.
[0155] [0155]FIG. 13 is a diagram showing a crank signal pattern of the three-cylinder engine according to Embodiment 5 of the present invention.
[0156] The crank signal pattern shown in FIG. 13 is detected by the crank angle sensor 15 , and is input to the electronic control unit 18 . The crank signal pattern is a signal output waveform of the crank angle sensor 15 with respect to the teeth of the crank signal vane 16 shown in FIG. 12.
[0157] The electronic control unit 18 is set so as to detect the trailing edge timing of the crank signal, and perform computation processing for each training edge.
[0158] The crank signal vane 16 rotates two times in the engine 1 cycle (720° CA). The angular gap between ignition strokes is 240° in a three-cylinder engine, and therefore the specific teeth of the crank signal vane 16 and the relative angular position of the engine differ between the first rotation and the second rotation of the crank signal vane 16 in the engine 1 cycle.
[0159] Also in Embodiment 5, there is performed computation of the missing tooth identification value K similarly to Embodiment 1 above, and detection of the number of missing teeth is performed with respect to the range of the missing tooth identification value K.
[0160] The electronic control unit 18 performs computation of the missing tooth identification value K described below for each crank signal detection similarly to Embodiment 1 above, and detection of the number of missing teeth is performed with respect to the range of the missing tooth identification value K.
K =( Tn− 1){circumflex over ( )}2/{( Tn− 2)* Tn}
[0161] Tn expresses the current crank signal period, Tn−1 expresses the previous crank signal period, and Tn−2 expresses the crank signal period before the previous crank signal period.
[0162] If K<2.25, then no missing teeth are detected. Further, if 2.25≦K<6.25, then one missing tooth is detected. In addition, if K≧6.25, then two missing teeth are detected.
[0163] A method of missing teeth detection is explained according to FIG. 13. Note that the term crank signal period as used here simply denotes the ratio of angular gaps.
[0164] If the crank signal detected this time is equal to 1 to 4, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K=1 2 ÷(1×1)=1. This corresponds to a case in which K<2.25, and therefore no missing teeth are detected.
[0165] If the crank signal detected this time is equal to 5, then Tn−2=1, Tn−1=1, and Tn=3, and therefore K=1 2 ÷(1×3)=0.33. This corresponds to a case in which K<2.25, and therefore no missing teeth are detected.
[0166] If the crank signal detected this time is equal to 6 , then Tn−2=1, Tn−1=3, and Tn=1, and therefore K=3 2 ÷(1×1)=9. This corresponds to a case in which K>6.25, and therefore two missing teeth are detected.
[0167] Two missing teeth detection is performed with a crank signal of 6, and therefore the angular position is detected as B 75 ° CA (75° CA before top dead center) (cylinder group A), or A 75 ° CA (45° CA after top dead center) (cylinder group A).
[0168] Similarly, if the crank signal detected this time is equal to 17, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷(1×1)=4. This corresponds to a case in which 2.25≦K<6.25, and therefore one missing tooth is detected.
[0169] One missing tooth detection is performed with a crank signal of 17, and therefore the angular position is detected as A 75 ° CA (45° CA after top dead center) (cylinder group B), or B 75 ° CA (75° CA before top dead center) (cylinder group B).
[0170] Similarly, if the crank signal detected this time is equal to 28, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷(1×1)=4. This corresponds to a case in which 2.25≦K<6.25, and therefore one missing tooth is detected.
[0171] One missing tooth detection is performed with a crank signal of 28, and therefore the angular position is detected as B 75 ° CA (cylinder group B), or A 75 ° CA (cylinder group B)
[0172] If the crank signal detected this time is equal to 39, then Tn−2=1, Tn−1=3, and Tn=1, and therefore K=3 2 ÷(1×1)=9. This corresponds to a case in which K≧6.25, and therefore two missing teeth are detected.
[0173] Two missing teeth detection is performed with a crank signal of 39, and therefore the angular position is detected as A 75 ° CA (cylinder group A), or B 75 ° CA (cylinder group A).
[0174] Similarly, if the crank signal detected this time is equal to 50, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷(1×1)=4. This corresponds to a case in which 2.25≦K<6.25, and therefore one missing tooth is detected.
[0175] One missing tooth detection is performed with a crank signal of 50, and therefore the angular position is detected as B 75 ° CA (cylinder group B), or A 75 ° CA (cylinder group B).
[0176] Similarly, if the crank signal detected this time is equal to 61, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷(1×1)=4. This corresponds to a case in which 2.25≦K<6.25, and therefore one missing tooth is detected.
[0177] One missing tooth detection is performed with a crank signal of 61, and therefore the angular position is detected as A 75 ° CA (cylinder group B), or B 75 ° CA (cylinder group B).
[0178] The crank angle reference position B 75 ° CA (cylinder group B) or A 75 ° CA (cylinder group B) is detected when one missing tooth is detected. Further, the reference position B 75 ° CA (cylinder group A) or A 75 ° CA (cylinder group A) is detected when two missing teeth are detected.
[0179] That is, the reference position B 75 ° CA (cylinder group A) exists in one position, the reference position B 75 ° CA (cylinder group B) exists in two positions, the reference position A 75 ° CA (cylinder group A) exists in one position, and the reference position A 75 ° CA (cylinder group B) exists in two positions during the engine 1 cycle period (720° CA) in the engine 1 cycle (720° CA) with the three-cylinder engine crank signal pattern shown in FIG. 13. A distinction therefore cannot be made with the crank signal between the angular position of the reference position B 75 ° CA and the reference position A 75 ° CA, and therefore the cam signal is also used to perform angular position detection and cylinder identification. Cam signal information necessary when performing cylinder identification by B 75 ° CA is information for distinguishing between B 75 ° CA and A 75 ° CA, and for distinguishing between the two positions of B 75 ° CA (cylinder group B). For example, three types of B 75 ° CA can be distinguished if the cam signal information is taken as follows:
B 75 ° CA (A) . . . (a) pattern;
B 75 ° CA (B) . . . (a) pattern and (b) pattern; and
A 45 ° CA (A), A 45° CA (B) . . . (c) pattern.
[0180] Cylinder identification can thus be performed by providing three types of information (cylinder identification signals) to the cam signal, and therefore the cam signal vane information can be simplified.
[0181] Embodiment 6
[0182] A crank angle detecting device for an internal combustion engine according to Embodiment 6 of the present invention is explained while referring to the diagrams.
[0183] The map of FIG. 10 is used when performing identification of the number of missing teeth in the missing tooth region, as in Embodiment 2 and Embodiment 4 above.
[0184] The electronic control unit 18 performs computation of the identification expressions described below for each crank signal detection, and detection of the number of missing teeth is performed with respect to the range of the identification value.
K 1=( Tn− 1)/( Tn− 2)
K 2=( Tn− 1)/ Tn
K =( K 1 +K 2)/2
[0185] Tn expresses the current crank signal period, Tn−1 expresses the previous crank signal period, and Tn−2 expresses the crank signal period before the previous crank signal period.
[0186] A method of missing teeth detection is explained according to FIG. 13. Note that the term crank signal period as used here simply denotes the ratio of angular gaps.
[0187] The correspondence between the missing tooth identification value K and missing tooth regions A, B, C, D, and E is as follows. The missing tooth region is A if K<1.5. Further, if 1.5≦K<2, then the missing tooth region is B. Further, if 2≦K<2.5, then the missing tooth region is C, and if 2.5≦K<3, then the missing tooth region is D. In addition, the missing tooth region is E if K≧3.
[0188] If the crank signal detected this time is equal to 1 to 4, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K1=1/1=1, K2=1/1=1, and K=(1+1)/2=1. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0189] If the crank signal detected this time is equal to 5, then Tn−2=1, Tn−1=1, and Tn=3, and therefore K1=1/1=1, K2=1/3=0.33, and K=(1+0.33)/2=0.67. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0190] If the crank signal detected this time is equal to 6, then Tn−2=1, Tn−1=3, and Tn=1, and therefore K1=3/1=3, K2=3/1=3, and K=(3+3)/2=3. This corresponds to a case in which K≧3, and therefore the missing tooth region E is detected.
[0191] In Embodiment 5 above, detection of two missing teeth is made when the crank signal is in the position of 6, but in Embodiment 6, missing tooth detection is implemented using the missing teeth number identification map of FIG. 10 for cases in which the distribution region of the missing tooth region detected coincides with the missing teeth number identification map. If the missing tooth region identified this time is taken as n, then it is distributed at this point in the missing tooth region A when the crank signal is from n−7 to n−1, and is distributed in the missing tooth region E when the crank signal is equal to n. However, identification is not performed for regions having a number that satisfies the map, and therefore missing tooth detection is not implemented.
[0192] Similarly, if the crank signal detected this time is equal to 7, then Tn−2=3, Tn−1=1, and Tn=1, and therefore K1=1/3=0.33, K2=1/1=1, and K=(0.33+1)/2=0.67. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0193] If the crank signal detected this time is equal to 8 to 15, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K1=1/1=1, K2=1/1=1, and K=(1+1)/2=1. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0194] If the crank signal detected this time is equal to 16, then Tn−2=1, Tn−1=1, and Tn=2, and therefore K1=1/1=1, K2=1/2=0.5, and K=(1+0.5)/2=0.75. This corresponds to a case in which K<1.5, and therefore the missing tooth region A is detected.
[0195] With crank signal positions from 10 to 16, the previously identified missing tooth region is equal to or greater than 10, and therefore identification of the region of the number satisfying the map is performed. However, since all the regions are the missing tooth region A, the distribution range of the missing tooth region coincides with the third missing teeth number identification map, and the number of missing teeth is identified as “none”.
[0196] If the crank signal detected this time is equal to 17, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K1=2/1=2, K2=2/1=2, and K=(2+2)/2=2. This corresponds to a case in which 2≦K<2.5, and therefore the missing tooth region C is detected.
[0197] In this case, if the crank signal is n−11, it is distributed in the missing tooth region E, if the crank signal is from n−10 to n−1, it is distributed in the missing tooth region A, and if the crank signal is n, it is distributed in the missing tooth region C. The distribution range of the missing tooth region therefore coincides with the first missing teeth number identification map, and the number of missing teeth is identified as “1”.
[0198] One missing tooth detection is performed with a crank signal of 17, and therefore the angular position is identified as A 75 ° CA (45° CA after top dead center) (cylinder group B), or B 75 ° CA (75° CA before top dead center) (cylinder group B).
[0199] Similarly, if the crank signal detected this time is equal to 28, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K1=2/1=2, K2=2/1=2, and K=(2+2)/2=2. This corresponds to a case in which 2≦K<2.5, and therefore the missing tooth region C is detected.
[0200] In this case, if the crank signal is n−11, it is distributed in the missing tooth region E, if the crank signal is from n−10 to n−1, it is distributed in the missing tooth region A, and if the crank signal is n, it is distributed in the missing tooth region C. The distribution range of the missing tooth region therefore coincides with the first missing teeth number identification map, and the number of missing teeth is identified as “1”.
[0201] One missing tooth detection is performed with a crank signal of 28, and therefore the angular position is detected as B 75 ° CA (cylinder group B), or A 75 ° CA (cylinder group B)
[0202] Similarly, if the crank signal detected this time is equal to 39, then Tn−2=1, Tn−1=3, and Tn=1, and therefore K1=3/1=3, K2=3/1=3, and K=(3+3)/2=3. This corresponds to a case in which K>3, and therefore the missing tooth region E is detected.
[0203] In this case, if the crank signal is n−10, it is distributed in the missing tooth region C, if the crank signal is from n−9 to n−1, it is distributed in the missing tooth region A, and if the crank signal is n, it is distributed in the missing tooth region E. The distribution range of the missing tooth region therefore coincides with the second missing teeth number identification map, and the number of missing teeth is identified as “2”.
[0204] Two missing teeth detection is performed with a crank signal of 39, and therefore the angular position is identified as A 75 ° CA (cylinder group A), or B 75 ° CA (cylinder group A)
[0205] Similarly, if the crank signal detected this time is equal to 50, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K1=2/1=2, K2=2/1=2, and K=(2+2)/2=2. This corresponds to a case in which 2<K<2.5, and therefore the missing tooth region C is detected.
[0206] In this case, if the crank signal is n−11, it is distributed in the missing tooth region E, if the crank signal is from n−10 to n−1, it is distributed in the missing tooth region A, and if the crank signal is n, it is distributed in the missing tooth region C. The distribution range of the missing tooth region therefore coincides with the first missing teeth number identification map, and the number of missing teeth is identified as “1”.
[0207] One missing tooth detection is performed with a crank signal of 50, and therefore the angular position is detected as B 75 ° CA (cylinder group B), or A 75 ° CA (cylinder group B)
[0208] Similarly, if the crank signal detected this time is equal to 61, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K1=2/1=2, K2=2/1=2, and K=(2+2)/2=2. This corresponds to a case in which 2≦K<2.5, and therefore the missing tooth region C is detected.
[0209] In this case, if the crank signal is n−11, it is distributed in the missing tooth region E, if the crank signal is from n−10 to n−1, it is distributed in the missing tooth region A, and if the crank signal is n, it is distributed in the missing tooth region C. The distribution range of the missing tooth region therefore coincides with the first missing teeth number identification map, and the number of missing teeth is identified as “1”.
[0210] One missing tooth detection is performed with a crank signal of 61, and therefore the angular position is detected as A 75 ° CA (cylinder group B), or B 75 ° CA (cylinder group B).
[0211] Two missing teeth detection is performed with the initial crank signal of 6, but with the next crank signal of 6, identification of the region of the number that satisfies the above-mentioned map is performed. If the crank signal is n−10, it is distributed in the missing tooth region C, and if the crank signal is from n−9 to n−1, it is distributed in the missing tooth region A. When the crank signal is n, it is distributed in the missing tooth region E. The distribution range of the missing tooth region therefore coincides with the second missing teeth number identification map, and the number of missing teeth is identified as “2”.
[0212] Two missing teeth detection is performed with the next crank signal of 6, and therefore the angular position is identified as B 75 ° CA (cylinder group A), or A 75 ° CA (cylinder group A).
[0213] In order to detect zero missing teeth, one missing tooth, ′and two missing teeth in Embodiment 5 above, threshold values are respectively set for classification, and detection of the number of missing teeth is performed. It is possible to set each of the classification threshold values for cases in which there is little variation in the crank signal period, but if there are large variations in the crank signal period, such as during startup, it is difficult to set the respective classification threshold values, and cases of erroneous detection of the number of missing teeth occur.
[0214] The number of missing teeth is not simply classified by threshold values in Embodiment 6, but rather, a plurality of missing teeth regions corresponding to each missing tooth are set, and the number of missing teeth is detected with respect to the distribution range of the missing tooth region (pattern), and therefore breadth of each missing tooth threshold value becomes larger, and missing tooth detection can be performed with good accuracy even for cases in which variations in the crank signal period are large.
[0215] The angular gap between missing teeth may be changed per missing tooth as shown in FIG. 14 as another example.
[0216] The missing tooth identification value K is computed, and detection of the number of missing teeth is performed with respect to the range of the missing tooth identification value K as another example, similar to Embodiment 5 above.
[0217] The crank angle reference position B 75 (C) or A 45 (C) is detected when one missing tooth is detected. Further, the reference position B 75 (B) or A 45 (B) is detected when two missing teeth are detected. Furthermore, the reference position B 75 (A) or A 45 (A) is detected when three missing teeth are detected.
[0218] As another example of Embodiment 6, the crank angle and the cylinder groups A, B, and C can be identified with respect to the crank signal. That is, B 75 and A 45 may be distinguished for cases of performing cylinder identification at B 75 with a three-cylinder engine. Cylinder identification can be performed by providing two types of information (cylinder identification signals) to the cam signal vane, and therefore the cam signal vane information can be simplified.
[0219] Embodiment 7
[0220] A crank angle detecting device for an internal combustion engine according to Embodiment 7 of the present invention is explained while referring to the diagrams.
[0221] [0221]FIG. 15 is a diagram showing a crank signal pattern of the four-cylinder engine according to Embodiment 7 of the present invention.
[0222] Missing teeth at angular gaps of 20 20 CA are established at two locations in each ignition stroke interval (180° CA) with a crank signal vane corresponding to a crank signal pattern of a four-cylinder engine shown in FIG. 15. In addition, the angular gap between the first missing tooth (one missing tooth) (crank signals 3 to 4 ) and the second missing tooth (one missing tooth) (crank signals 6 to 7 ) is set to 20° CA in the first half ignition stroke interval (180° CA), and the angular gap between the first missing tooth (one missing tooth) (crank signals 20 to 21 ) and the second missing tooth (one missing tooth) (crank signals 22 to 23 ) is set to 10° CA in the second half ignition stroke interval (180° CA).
[0223] Similarly to Embodiment 1 above, the electronic control unit 18 performs computation of the missing tooth identification value K described below for each crank signal detection and detection of the number of missing teeth is performed with respect to the range of the missing tooth identification value K.
K =( Tn− 1){circumflex over ( )}2/{( Tn− 2)* Tn}
[0224] Tn expresses the current crank signal period, Tn−1 expresses the previous crank signal period, and Tn−2 expresses the crank signal period before the previous crank signal period.
[0225] If K<2.25, then no missing teeth are detected. Further, if K≧2.25, then one missing tooth is detected.
[0226] A method of missing teeth detection is explained according to FIG. 15. Note that the term crank signal period as used here simply denotes the ratio of angular gaps.
[0227] If the crank signal detected this time is equal to 1 to 3, then Tn−2=1, Tn−1=1, and Tn=1, and therefore K=1 2 ÷1×1=1. This corresponds to a case in which K<2.25, and therefore no missing teeth are detected.
[0228] If the crank signal detected this time is equal to 4, then Tn−2=1, Tn−1=1, and Tn=2, and therefore K=1 2 ÷(1×2)=0.5. This corresponds to a case in which K<2.25, and therefore no missing teeth are detected.
[0229] If the crank signal detected this time is equal to 5, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷1×1=4. This corresponds to a case in which K≧2.25, and therefore one missing tooth is detected.
[0230] If the crank signal detected this time is equal to 8, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷1×1=4. This corresponds to a case in which K≧2.25, and therefore one missing tooth is detected.
[0231] Detection of one missing tooth is performed here with respect to a crank signal of 8 here, and the gap with the crank signal of of the previously detected one missing tooth is 3 (=8−5), and therefore the crank angle reference position B 75 ° CA (A) is detected.
[0232] Missing tooth detection is performed with respect to a crank signal of 22. The crank signal of the previously detected one missing tooth is 8, and the gap is not 3 or 2 (≠22−8), and therefore the position of the crank angle signal of 22 is not identified as B 75 ′ CA.
[0233] Next, missing tooth detection is performed with respect to a crank signal of 24. The crank signal of the previously detected one missing tooth is 22, and the gap is 2 (=24−22), and therefore the reference position of the crank angle is identified as B 75 ° CA (B).
[0234] [0234]FIG. 16 is a flowchart showing action of the crank angle detecting device for the internal combustion engine according to Embodiment 7 of the present invention.
[0235] Actions up to performing missing tooth detection by using the missing tooth identification value K are similar to those of Embodiment 1 described above.
[0236] The electron control unit 18 finds the gap (N) (crank signal number) (N) between the previously detected missing tooth crank signal and the currently detected missing tooth crank signal in a step 501 when performing missing signal detection.
[0237] Identification of the signal number gap is performed next in a step 502 . Processing moves to a step 503 if N=3, and to a step 504 if N=2. Crank angle reference position identification is not performed for cases in which N is neither 2 nor 3.
[0238] The currently detected crank angle position is identified as the crank angle reference position B 75 ° CA (A) in the step 503 .
[0239] The currently detected crank angle position is identified as the crank angle reference position B 75 ° CA (B) in the step 504 .
[0240] In Embodiment 7, the crank angle and the cylinder groups A and B can be identified with respect to the crank signal. That is, in a four-cylinder engine, cylinder identification can be performed by providing two types of information (cylinder identification signals) to the cam signal vane, and therefore the cam signal vane information can be simplified.
[0241] Embodiment 8
[0242] A crank angle detecting device for an internal combustion engine according to Embodiment 8 of the present invention is explained while referring to the diagrams.
[0243] [0243]FIG. 17 is a diagram showing a crank signal pattern of the six-cylinder engine according to Embodiment 8 of the present invention.
[0244] Missing teeth at angular gaps of 20° CA are established at two locations in each ignition stroke interval (120° CA) with a crank signal vane corresponding to a crank signal pattern of a six-cylinder engine shown in FIG. 17.
[0245] In addition, the angular gap between the first missing tooth (one missing tooth) (crank signals 2 to 3 ) and the second missing tooth (one missing tooth) (crank signals 5 to 6 ) is set to 20° CA in the first ignition stroke interval (120° CA), and the angular gap between the first missing tooth (one missing tooth) (crank signals 11 to 12 ) and the second missing tooth (one missing tooth) (crank signals 15 to 16 ) is set to 300 CA in the second ignition stroke interval (120° CA) The angular gap between the first missing tooth (one missing tooth) (crank signals 23 to 24 ) and the second missing tooth (one missing tooth) (crank signals 25 to 26 ) is set to 10° CA in the third ignition stroke interval (120° CA).
[0246] The electronic control unit 18 performs computation of the missing tooth identification value K described below for each crank signal detection similarly to Embodiment 7 above, and detection of the number of missing teeth (whether there are missing teeth or not) is performed with respect to the range of the missing tooth identification value K.
[0247] A method of missing teeth detection is explained according to FIG. 17. Note that the term crank signal period as used here simply denotes the ratio of angular gaps.
[0248] If the crank signal detected this time is equal to 4, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷1×1=4. This corresponds to a case in which K≧2.25, and therefore one missing tooth is detected.
[0249] Next, if the crank signal detected this time is equal to 7, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷1×1=4. This corresponds to a case in which K≧2.25, and therefore one missing tooth is detected.
[0250] Detection of one missing tooth is performed here with respect to a crank signal of 7 here, and the gap with the crank signal of 4 of the previously detected one missing tooth is 3 (=7−4), and therefore the crank angle reference position B 75 ° CA (A) is detected.
[0251] If the crank signal detected this time is equal to 13, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷1×1=4. This corresponds to a case in which K>2.25, and therefore one missing tooth is detected. However, the gap with the crank signal of 7 of the previously detected one missing tooth is 6 (=13−7), and therefore detection of the crank angle position is not performed.
[0252] Next, if the crank signal detected this time is equal to 17, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷1×1=4. This corresponds to a case in which K≧2.25, and therefore one missing tooth is detected.
[0253] Detection of one missing tooth is performed here with respect to a crank signal of 17 here, and the gap with the crank signal of 13 of the previously detected one missing tooth is 4 (=17−13), and therefore the crank angle reference position B 75 ° CA (B) is detected.
[0254] If the crank signal detected this time is equal to 25, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷1×1=4. This corresponds to a case in which K≧2.25, and therefore one missing tooth is detected. However, the gap with the crank signal of 17 of the previously detected one missing tooth is 8 (=25−17), and therefore detection of the crank angle position is not performed.
[0255] Next, if the crank signal detected this time is equal to 27, then Tn−2=1, Tn−1=2, and Tn=1, and therefore K=2 2 ÷1×1=4. This corresponds to a case in which K≧2.25, and therefore one missing tooth is detected.
[0256] Detection of one missing tooth is performed here with respect to a crank signal of 27 here, and the gap with the crank signal of 25 of the previously detected one missing tooth is 2 (=27−25), and therefore the crank angle reference position B 75 ° CA (C) is detected.
[0257] In Embodiment 8, the crank angle and the cylinder groups A, B, and C can be identified with respect to the crank signal. That is, in a six-cylinder engine, cylinder identification can be performed by providing two types of information (cylinder identification signals) to the cam signal vane, and therefore the cam signal vane information can be simplified.
[0258] Next, another example of Embodiment 8 is described.
[0259] [0259]FIG. 18 is a diagram showing a crank signal pattern of the three-cylinder engine according to another example of Embodiment 8 of the present invention.
[0260] Missing teeth having an angular gap of 20° CA are established at two locations in each half angular region (120° CA) of the ignition stroke interval (240° CA) with the crank signal vane corresponding to the three-cylinder engine crank signal pattern shown in FIG. 18.
[0261] [0261]FIG. 18 is a diagram showing the relationship between the crank signal pattern of the three-cylinder engine 1 cycle (720° CA) and the angular positions.
[0262] The electronic control unit 18 performs current missing tooth detection, and the angular position identification is performed with respect to the crank signal gap (N) with the previously detected missing tooth. That is, if the gap N=3, the crank angle reference position B 75 ° CA (A) or A 75 ° CA (A) is identified. Further, the crank angle reference position B 75 ° CA (B) or A 75 ° CA (B) is identified if the gap N=4. In addition, the crank angle reference position B 75 ° CA (C) or A 75 ° CA (C) is identified if the gap N=2.
[0263] In another example of Embodiment 8, the crank angle and the cylinder groups A, B, and C can be identified with respect to the crank signal. That is, when cylinder identification is performed at B 75 in a three-cylinder engine, B 75 (A), B 75 (B), and A 45 may be distinguished. Cylinder identification can be performed by providing two types of information (cylinder identification signals) to the cam signal vane, and therefore the cam signal vane information can be simplified.
[0264] A cylinder group identifying means (missing teeth) is thus set in the crank signal vane 16 in accordance with each of the embodiments described above, and therefore the information that needs to be set into the cam signal vane in order to perform cylinder identification can be simplified.
[0265] Plural ignition strokes are needed for specific cylinder identification for cases in which there is no cylinder group identifying means in the crank signal vane, the cam signal vane diameter is small, and a complex cylinder identification signal cannot be set. However, the cam signal pattern (cylinder identification signal) is simplified, and therefore information (cylinder identification signal) can also be set in the small diameter cam signal vane, and cylinder identification can be performed in one ignition stroke.
[0266] Further, although the cam signal vane is conventionally formed by precision processing, the degree of difficulty in processing can be reduced by simplifying the cam signal pattern, and therefore costs can be reduced.
[0267] In addition, although it is necessary to use a highly accurate sensor in order to detect a complex cam signal pattern conventionally, the sensor accuracy can be lowered, and costs can be reduced.
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The present invention has: a crank signal vane in which teeth are provided on a circumference at predetermined crank angles, and a first missing tooth portion having one missing tooth and a second missing tooth portion having two missing teeth are established; a crank angle sensor for outputting a pulse shape crank signal pattern corresponding to the teeth; and an electronic control unit for calculating a crank signal period based on the crank signal pattern, computing a missing tooth identification value based on the calculated crank signal period; detecting the number of missing teeth based on the computed missing tooth identification value, detecting a crank angle reference position for cases in which the detected number of missing teeth is one or two, and identifying a cylinder group.
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FIELD OF THE INVENTION
The invention relates generally to superconducting structures; in particular, it relates to a superconducting film grown on a flexible ceramic substrate.
BACKGROUND ART
If the high-T c superconductors are to be used in practical power applications, either for power transmission or for magnetic windings, they will need to be drawn as wire or grown as films on flexible substrates, which will probably be wound on metal support cables or magnetic yokes. To date, three approaches have achieved significant results: the extrusion of bismuth-based superconductors, melt-textured growth of bulk YBa 2 Cu 3 O 7-x (YBCO), and growth of oriented thin films on flexible substrates.
Many groups have reported successful epitaxial growth of high quality thin films on singly crystalline substrates. High quality is ultimately defined by high values of the superconducting transition temperature T c and the critical current J c defining the upper limits of superconducting behavior. While singly crystalline substrates may be satisfactory for applications resembling semiconductor integrated circuits, their rigidity and expense preclude their use in many applications of commercial significance, for example, interconnects between computer boards, commercial power lines, and magnet windings. Therefore, flexible substrates have been investigated. Norton et al. have disclosed substrates of yttria-stabilized zirconia (YSZ) in "Y-Ba-Cu-O thin films grown on rigid and flexible polycrystalline yttria-stabilized zirconia by pulsed laser ablation," Journal of Applied Physics, volume 68, 1990, pp. 223-227. Zirconia (ZrO 2 ) assumes a monoclinic (or tetragonal for thin films) crystal structure but is stabilized in a cubic crystal structure when combined with yttria (Y 2 O 3 ). The rigid polycrystalline YSZ substrates were stabilized with 3 mole % of Y 2 O 3 , while the thin flexible sintered zirconia substrates were prepared using a proprietary and undisclosed sheet-forming method. When YBa 2 Cu 3 O 7-x (YBCO) was deposited on the rigid substrates, it exhibited a T c of ˜89° K. (a few degrees below the best transition temperatures for YBCO epitaxially grown on singly crystalline substrates), but when grown on the flexible zirconia substrate T c was degraded to about 85° K. Norton et al, noted that the randomly oriented, polycrystalline rigid YSZ substrate produced thin films of YBCO having its c-axis highly aligned perpendicularly to the substrate. Narumi et al. have disclosed growing YBCO on a flexible metallic substrate in "Superconducting YBa 2 Cu 3 O 6 .8 films on metallic substrates using in situ laser deposition," Applied Physics Letters, volume 56, 1990, pp. 2684-2686. They used a buffer layer of 8 mole % YSZ between the YBCO and the flexible metallic substrate, which produced transition temperatures T c of no more than 83° K. This further degradation in T c is considered unsatisfactory. They considered that the buffer layer reduced the effect of the oxidized metallic surface but that the buffer layer did not prevent the substrate grains from producing granular boundaries in the YBCO.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a superconducting thin film having a high transition temperature that is grown on a flexible substrate.
The invention can be summarized as a superconducting thin film, for example, of YBa 2 Cu 3 O 7-x , grown on a fully yttria-stabilized (between 8 and 18 mole %, preferably 9 mole %) zirconia thin film that is grown on a flexible, partially yttria-stabilized (less than 8 mole % and preferably 3 mole %) zirconia substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of the dependence of strength upon the degree of stabilization in yttria-stabilized zirconia.
FIG. 2 is a cross-sectional view of an embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The stabilization of zirconia by yttria is complete only when yttria is present in yttria-stabilized zirconia (YSZ) to a fraction above a lower limit of between 8 and 9 mole %. Below this level, separate crystallites of the monoclinic and cubic phases are present. Above a fraction of about 18 mole %, the yttria and zirconia phase separate. Within this range of 8 to 18 mole %, YSZ is fully stabilized. The precise value of the lower limit tends to fluctuate so that it is better to use 9 mole % to ensure full stabilization. FIG. 1 illustrates the flexural strength of yttria-stabilized zirconia as a function of weight percentage and mole percentage of yttria in crystalline YSZ. Around 3 mole %, the YSZ has maximum flexural strength, about five times the value for fully stabilized YSZ. A very similar plot is obtained when the fracture toughness is measured. The Vickers hardness increases with stabilization percentage up to about 8 mole %. Thus, a 3 mole % stabilized YSZ substrate provides the desired flexibility. However, to achieve the best transition temperatures, a more fully stabilized substrate is desirable.
An embodiment of the invention is illustrated in cross-section in FIG. 2. The structure is grown on a substrate 10 of 3 mole % YSZ, that is, having a composition of maximum flexibility. A thin-film buffer layer 12 of fully stabilized or 8 mole % or greater YSZ is grown on the substrate 10. A superconducting thin film 14 of, for example, YBa 2 Cu 3 O 7-x (YBCO) is grown on the buffer layer 12. When electrical leads 16 and 18 are attached to the YBCO thin film 14 and its temperature is reduced to below its superconducting transition temperature T c , it conducts electrical power with zero resistance and thus no power loss.
The 3 mole % YSZ substrate 10 provides the structural strength while maintaining its flexibility. Although 3 mole % YSZ appears to be the optimal composition, adequate strength, toughness, and hardness are obtained over the compositional range of 2 mole % to 5 mole % YSZ. The substrate 10 of this 3 mole % composition is commercially available but is likely to be polycrystalline. It typically has a flexural strength of ˜1500 MPa and a fracture toughness of ˜8 MPa. The 8 mole % buffer layer 12 is a thin film so that it is inherently flexible. Its fully stabilized composition insures a good crystalline structure and thus acts as a good template and chemical barrier for the deposition of superconducting material of high T c .
EXAMPLE
The invention was experimentally verified using pulsed laser ablation for the deposition of both the fully stabilized YSZ layer 12 and the YBCO layer 14. This deposition method is well known in the deposition of superconducting films and has been described in detail by Singh et al. in "Theoretical model for deposition of superconducting thin films using pulsed laser evaporation technique," Journal of Applied Physics, volume 68, 1990, pp. 233-246. For our depositions, a KrF excimer laser delivered optical pulses of 248 nm radiation with pulse widths of 20 ns, pulse energy densities of 1.5 J/cm 2 on stoichiometric targets, and pulse repetition rates of 5 Hz. The targets and the substrate were exposed to an oxygen partial pressure of ˜75 mTorr. The substrate holder holding the substrate 10 was held at a temperature of ˜800° C. for the fully stabilized YSZ layer 12 and at ˜740° C. for the YBCO layer 14.
The partially stabilized 3 mole % YSZ substrate 10 was in the form of a thin tape, about 0.05 mm thick and having a bend radius of about 1 cm. It is commercially available from Marketech International of Pittsburgh, Pa.
The target for the deposition of the fully stabilized buffer layer 12 was a single crystal of stoichiometric composition for 9.5 mole % YSZ, which is available from Commercial Crystal Laboratories, Inc. of Naples, Fla. The buffer layer 12 was deposited to a thickness of about 100 nm.
In fabricating the sample of the example, the chamber was brought to atmosphere between depositions of the two layers to replace the target on the rotating holder. However, it is preferable that the targets were held on a carousel of the sort described by Chase et al. in "Multilayer high T c thin film structures fabricated by pulsed laser deposition of Y-Ba-Cu-O," Journal of Material Research, volume 4, 1989, pp. 1326-1329. During the depositions of the YSZ and the YBCO, the carousel would rotate the chosen target about the target axis with the laser beam hitting a circumference of the target. Between the depositions, the carousel itself would rotate about its own axis to place the YBCO target in the laser beam. Thereby, the buffer layer 12 would not be exposed to ambient conditions between the deposition steps.
The target for the laser deposition of the YBCO layer 14 was a pellet of sintered powder of YBCO. The YBCO was deposited to a thickness of about 200 nm.
After the depositions, the film was cooled to room temperature at the rate of 12° C./min in 200 Torr of oxygen.
The resistance of the film as a function of temperature was measured by a four-probe DC technique. The YBCO film of the invention exhibited a superconducting transition temperature T c of 90° K. with a transition width ΔT c of 1° to 1.5° K. The ratio R 300 /R 95 of the room temperature resistance to the resistance at 95° K., just above the transition, was 2.2.
The critical current density, J c at which superconductivity deteriorates (such that a voltage drop of 1 μV/cm is observed along the conductor) was estimated both by magnetization measurements and by I-V measurements using 125 μm-wide and 2 mm-long bridges. At 77° K. and zero applied magnetic field, J c was 0.9×10 4 A/cm 2 .
The crystallography of the film was determined by x-ray diffraction and transmission electron microscopy (TEM). The diffraction pattern was consistent with a c-axis orientation of the film, and there were no discernible reflections from other orientations. The TEM micrographs showed that the 100 nm fully stabilized YSZ buffer layer did not stop substrate grain boundaries from propagating into the YBCO film. Furthermore, it appeared that silicon contaminants in the substrate diffused into the grain boundaries of the YBCO film.
COMPARATIVE EXAMPLE 1
A YBCO film was grown on the 3 mole % YSZ substrate without an intermediate fully stabilized YSZ buffer layer. This film also exhibited a superconducting transition temperature T c of 90° K.; however, its transition width ΔT c was 2° to 3° K. Its temperature ratio R 300 /R 95 was 1.9. Its critical current J c was less than 10 3 A/cm 2 . Its x-ray pattern showed that the film was predominantly oriented along the c-axis, but the presence of (013), (011), and (103) reflections indicated a significant amount of YBCO of other orientations.
COMPARATIVE EXAMPLE 2
A YBCO film was grown directly on a singly crystalline substrate of 9 mole % fully stabilized YSZ having a (100) orientation. Its transition temperature T c was 91° K. Its critical current J c was 4:0×10 6 A/cm 2 . Its temperature ratio R 300 / R 95 was about 3.
COMPARATIVE EXAMPLE 3
A YBCO film was laser deposited on a 3 mole % buffer layer which had been itself laser deposited on a 3 mole % flexible tape. The superconducting properties degraded over those of the first comparative example in which the YBCO was deposited directly on the tape. The off-axis growths of the YBCO were about the same.
The various samples of the examples were electrically tested in applied magnetic fields. In general, the superconducting properties were improved with the use of a fully stabilized YSZ buffer layer.
These data show that the fully stabilized YSZ buffer layer on a partially stabilized, flexible YSZ substrate provides significantly larger critical currents in YBCO than YBCO films deposited directly on the flexible YSZ. The buffer layer apparently eliminates off-axis growth of the YBCO.
Although the invention has been described with reference to YBCO, almost all of the high-T c oxide superconductors have crystal structures similar to that of YBCO and exhibit similar superconducting properties, for example, the bismuth and thallium cuprate superconductors, and the bismuth potassium oxide superconductors. Therefore, the fully stabilized YSZ buffer layer of the invention can be beneficially used with all these other superconductors as well. Although pulsed laser ablation was used in the disclosed examples, the invention may be practiced with other deposition techniques, e.g., magnetron sputtering.
The invention thus provides a superconducting structure that is flexible but displays high superconducting transition temperatures and high critical currents. Therefore, it can be advantageously used in applications requiring the transmission of significant amounts electrical power over significant distances.
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A flexible superconducting wire element comprising a flexible tape of partially stabilized (˜3 mole % yttria) yttria-stabilized zirconia (YSZ), a buffer layer of fully stabilized (between 8 and 18 mole % yttria, preferably 9 mole %) YSZ deposited on the flexible tape, and a high-temperature, perovskite superconductor such as YBaCuO deposited on the buffer layer. The tape provides the strength while remaining flexible. The buffer layer is flexible because of its thinness (˜100 nm), but provides a good crystallographic template for the growth of oriented perovskite superconductors. Thereby, the superconducting properties of the wire element approach those of a superconducting film deposited on a rigid substrate.
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FIELD OF THE INVENTION
This invention relates to an aqueous coating process for use with synthetic fibers. In particular, this invention relates to a coating process that can be effectively employed with both solution dyed nylon yarn and non-solution dyed nylon yarn as well as with polyester yarns. Specifically, this invention relates to a water dispersible coating based upon polyvinyl acetate.
BACKGROUND OF THE INVENTION
Nylon and polyester yarns, regardless of the number of plies, are generally not suitable for use in industrial sewing applications unless they are bonded with a polymeric coating that encircles, or encapsulates, the yarn. The coating protects the twisted yarn from breaking and unraveling into the individual cords. An uncoated yarn used in industrial sewing applications will experience fraying and a significant number of breaks due to the high line speeds, significant tension, and significant friction.
Coating compositions, or bonding agents, that are employed with nylon and polyester fibers are well known in the art. Coatings based on low molecular weight nylons in organic solvents are common. Typical solvents employed in the various coating processes of the prior art include methanol and methylene chloride. Such systems pose fire, health, and environmental hazards and are expensive. These organic solvents are also prone to cause leaching of dye from the yarns. Additionally, the use of such systems may in the future become limited due to governmental regulations.
Between methanol and methylene chloride, the concomitant hazards associated with the use of methylene chloride are appreciably more severe than those associated with the use of methanol. As such, between the two, the use of methanol in coating systems is preferred. This preference is apparent in numerous prior art processes in which nylon yarns are coated. Unfortunately, the use of methanol systems to coat polyester yarns with common coatings, such as the aforementioned low molecular weigh nylons, has not proved to be as efficacious. In polyester coating operations, the use of methylene chloride is therefore more common. As such a coating process that could effectively be employed for both nylon and polyester yarns would be desirable. Even more desirable would be such a coating process that could be employed in an aqueous environment without the need for organic solvents. An aqueous based system would be less expensive, less prone to dye leaching concerns, and less likely to be subject to future governmental regulations.
Another problem with prior art processes used for the coating of nylon and polyester fibers relates to the practice of finishing. Nylon yarns can generally be divided into two categories: solution dyed yarn and non-solution dyed yard. For solution dyed yarns, a selected pigment or other colorant is added to the base polymer prior to extrusion. For non-solution dyed yarn, a selected dye is provided via a dye bath after extrusion of the base polymer into fiber. The dye penetrates the fibers to provide the finished color.
For both solution and non-solution dyed nylon yarns and for polyester yarns, the extruded and spun yarn, individually or in combination with a second, third, fourth yarn, etc., is twisted into a helical structure, often having been drawn in the process, and collected onto a bobbin. During these steps, a finish consisting of oil and other ingredients is applied to the yarn. The finish reduces static and aids in the processing of the thread by decreasing the potential for breaking of the yarn in the drawing and twisting process.
A problem with the finish is that if not removed from the yarn prior to the coating operation, the residual finish can prevent or substantially interfere with the bonding between the coating and the base fiber. In non-solution dyed yarn, this problem is ameliorated due to other necessary, if not desirable, process steps. After finishing, the uncolored non-solution dyed yarn is passed through the equivalent of a dye bath, without the dye, in which the yarn is subjected to a wash, or scouring, consisting of boiling water and a detergent. The washed non-solution dyed yarn is then dyed by passing the yarn through a conventional dye bath. The finish is removed to allow the dye to effectively penetrate the nylon yarn. Emerging from the wash and dye steps, the now colored yarn has no, or very little, residual oil left on its surface.
Solution dyed yarn emerging from the extrusion and twisting steps is already colored as desired and as such the use of a separate dying step and the obligatory scouring bath is unnecessary. As one might imagine however, bypassing the scouring bath also results in a solution dyed yarn having residual oil from the finishing procedure on its surface. The traditional low molecular weight nylon coatings can not effectively displace the residual oil from the surface of the solution dyed yarn. The resulting coating obtained without first removing the residual oil is imperfect and provides insufficient appearance retention. This has necessitated that the solution dyed yarn also be subjected to a washing or scouring process to remove the residual oil. This additional process step is thus inefficient and costly. The need to conduct a scouring operation is also apparent in most prior art coating processes used for polyester yarns.
Accordingly, a coating process that could be used effectively for both non-solution dyed yarn and solution dyed yarn as well as polyester yarn, without the necessity of an additional washing and scouring step, would be extremely desirable. Thus, there is a need for a coating process that could be used effectively for both nylon and polyester yarns, utilize an aqueous dispersion system rather than a system in which a solvent such as methanol or methylene chloride is necessary, and result in an effective coating for the various yarns without the necessity of a scouring process to remove residual finishing oil.
SUMMARY OF THE INVENTION
The present invention meets these and other needs by providing an aqueous coating system in which polyvinyl acetate homopolymers and copolymers are used as the bonding agent. More than one polyvinylacetate may be utilized to achieve the coating. The polyvinyl acetate system is effective for the coating of both types of nylon yarns as well as for polyester yarns.
The need to employ a separate scouring operation for the various yarns is minimized with the polyvinyl acetate and water system. The need for the separate scouring operation is further reduced by the inclusion of a coupling agent in the polyvinyl acetate/ water coating emulsion.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Nylon and polyester yarns can be made by a variety of methods well known in the art. The present disclosure relates to methods of treatment of the yarns after they are initially produced. It is anticipated that the methods presently disclosed can be utilized with any of the aforementioned methods for producing the initial nylon and polyester yarns.
In one embodiment of the invention, the aqueous coating system utilizing polyvinyl acetate as the bonding agent is used to bond non-solution dyed yarn. In accordance with this embodiment, the non-solution dyed yarn emerges from an extruder or equivalent device. The yarn is spun and a traditional finish oil is applied. The yarn is then subjected to a traditional dye bath operation. Such a dye bath will often contain a target dye and a detergent dissolved or dispersed in boiling water.
The dyed yarn is then subjected to the bonding operation. The yarn is passed through a bath containing a stable dispersion of polyvinyl acetate in water. The polyvinyl acetate bonding agent will typically be present in the form of a copolymer although homopolymers may also be used. Copolymers containing ethylene are particularly common. The characteristics of the coating bath, water temperature, concentration of polyvinyl acetate in the bath, percentage vinyl acetate in the polyvinyl acetate polymer, and time in the bath, will vary with other process parameters, including but not limited to the desired coating thickness and process line speeds. Such determinations are within the capabilities of one of ordinary skill in the art having the benefit of this disclosure.
After the coating operation, the coated fiber is passed through a drying operation. Any of the drying procedures commonly used in the art can be employed with the disclosed process as long as temperatures are maintained below those that would bring about melting of either the coating or the underlying thread. Temperatures ranging from about 200-600° F. are acceptable, with temperatures ranging from about 400-500° F. being preferred. The use of an infrared heater to effectuate drying is particularly preferred.
The yarn thus obtained exhibits a more consistent coating and is less sensitive to fraying and breaking during use that a comparable yarn obtained with a coating operation employing a low molecular weight nylon in methanol.
Depending upon the utilized dye and desired end color, one making use of this disclosure may still find it necessary to subject the non-solution dyed nylon yarn to a scouring operation prior to dying to substantially remove the finish oil. However, even in cases where it is necessary to substantially remove the finishing oil prior to dying, the presently disclosed coating operation is more tolerant of residual oil levels than prior art coating processes.
In certain instances in which the coating obtained via the disclosed process is not sufficiently resistant to subsequent processing, a coupling agent can be utilized to improve bonding. The coupling agent facilitates bonding by penetrating the oil layer and provided a link between the bonding agent and the yarn. Depending on the coupling agent, the linkage with either the bonding agent or the yarn may be due to either entanglement or reactive coupling. The coupling agent when used in this manner is added to the coating bath. As one might expect, the use of a coupling agent as indicated has a lesser effect when the oil has been substantially removed to facilitate maximum uptake of dye. The use of a coupling agent in this manner is more readily adaptable to the presently disclosed process than prior art processes as the presence of methanol, methylene chloride, or other organic solvents can often have deleterious effects on the performance of the coupling agent.
Any of the traditional coupling agents can be employed, including those based on silane, siloxane, titanate, and zirconate. Coupling agents based upon silane are particularly preferred.
In accordance with another embodiment of the invention, the aqueous coating system utilizing polyvinyl acetate is used to bond solution dyed yarn. In solution dyed yarn operations, unlike non-solution dyed yarn operations, there is no independent need to conduct a separate scouring operation in order to achieve the desired end color. As previously indicated, dying of solution dyed yarn is achieved by adding dye to the polymer prior to the spinneret or equivalent device.
Again, in certain instances in which the coating obtained via the disclosed process is not sufficiently resistant to subsequent processing, a coupling agent can be utilized to improve bonding. As was the case with non-solution dyed nylon yarn, the coupling agent effectuates bonding by penetrating the oil layer.
In accordance with another embodiment of the invention, the aqueous coating system utilizing polyvinyl acetate is used to bond polyester yarn. As previously indicated, a problem with prior art coating systems is that the same coating systems can not be effectively employed for both nylon and polyester yarns. While low molecular weight nylons have been used as coatings for both nylon yarns and polyester yarns, methanol has traditionally been used as the solvent for nylon yarns while methylene chloride has traditionally been used as the solvent for polyester yarns. The inability to use the same solvent/coating system for both nylon and polyester yarns is due to the difference in surface energy between the nylon and polyester yarns.
An advantage of the present coating system is that the polyvinyl acetate in water system can be used for both nylon and polyester yarns. When the present coating system is utilized to bond polyester yarn, it is employed or applied in the same manner as previously described for nylon yarns.
An additional advantage of the present coating process, whether employed with nylon or polyester yarns, is that the aqueous systems, in contrast to systems employing organic solvents like methanol or methylene chloride, are not as prone to dye leach concerns.
In certain instances and for certain applications it may be desirable to add other additives. Such additives include other film forming polymer emulsions, adhesion promoters, plasticizers, wetting agents, antifoaming agents, and UV stabilizers, including both UV blockers and UV absorbers.
In the various embodiments of the present coating process, the vinyl acetate polymers will comprise between 10 and 100% of the total weight of the emulsion. Preferably, the polyvinyl acetate polymers will comprise between 50 and 80% by weight of the emulsion. When employed, additional additives preferably will be present in the following amounts: coupling agents (about 0.1 to about 2.0%), UV stabilizers (about 1.0 to about 50%), antifoaming agents (about 0.1 to about 1.0%), wetting agents (about 0.1 to about 5.0%), plasticizers (about 1.0 to about 20%), and adhesion promoters (about 3 to about 40%).
EXAMPLES
The following examples are provided to illustrate the present invention. However, it should be understood that the examples provided do not represent the entire scope of the present process.
Three coating emulsions, exemplary of the present process, were prepared as follows. Percentages represent the amount by weight of the total additives.
Additives*
Function
A
B
C
Flexthane ® 620
acrylic/urethane emulsion
24.0
—
—
Flexbond ® 325
vinyl acetate emulsion
—
23.88
29.85
Vinac ® 521BP
vinyl acetate emulsion
40.0
—
—
Airflex ® 426
vinyl acetate emulsion
16.0
11.94
5.97
etherified monool
wetting agent
0.5
0.5
0.5
Foamaster ® VF
antifoaming agent
0.02
—
—
Z-6020 ®
coupling agent
0.2
—
—
Z-6040 ®
coupling agent
0.2
—
—
aqueous latex containing
UV stabilizer
—
23.88
23.88
a UV absorbing polymer
water
19.08
39.80
39.80
*Flexthane ® 620 is a acrylic/urethane polymer emulsion that additionally contains 1-methyl-2-pyrrolidone and is available from Air Products. Flexbond ® 325 is a vinyl acetate-butyl acrylate copolymer emulsion and is available from Air Products. Vinac ® 521BP, also available from Air Products, is
#a vinyl acetate polymeric emulsion. Airflex ® 426 is a vinyl acetate polymeric emulsion available from Air Products that also contains a small amount of formaldehyde. The etherified monool employed was a decyl alcohol with six moles of ethylene oxide. Foamaster ® VF, a product of the Henkel Corporation, is a
#proprietary blend containing petroleum derivatives (oil mist). Z-6020 ® is a silane coupling agent available from Dow Corning containing ethylene diaminepropyl trimethoxysilane as a primary ingredient. Z-6040 ® is a silane coupling agent available from Dow Corning containing glycidoxypropyl trimethoxysilane
#as a primary ingredient. Acceptable aqueous latexes containing UV absorbing polymer include those taught in U.S. Pat. No. 5,629,365 containing vinyl functionalized monomers of benzotriazole or benzophenone.
Both nylon and polyester yarns were prepared using the indicated coating compositions. Yarns of varying denier, ranging from 70 to 630, were coated. These yarns were compared to similar yarns coated by traditional prior art processes, methanol and low molecular weight nylon for nylons and methylene chloride and low molecular weight nylon for polyester.
All yarns prepared with the vinyl acetate coating exhibited bonds that were equivalent to or better than bonds on yarns prepared with the prior art coatings. Additionally, the bonds prepared with vinyl acetate were softer. Softer threads are desirable because they generate less heat during high speed sewing.
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An aqueous, coatable, thermally condensable composition is disclosed. The coating is based on dispersions of vinyl acetate polymers in water. Uniquely, the coating can be advantageously used for both nylon and polyester yarns. The coated yarns exhibit performance equivalent to or better than coated yarns based on traditional compositions.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of identically-titled application Ser. No. 13/105,255 filed May 11, 2011, now abandoned, and also claims the benefit of Provisional Application Ser. No. 61/461,923, filed Jan. 25, 2011, and Provisional Application Ser. No. 61/463,373, filed Feb. 16, 2011, all of which are incorporated by reference herein in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is broadly concerned with improved apparatus and methods for closure of wounds in the tissue of patients, and especially wounds attendant to endovascular interventions, such as percutaneous cardiac intervention (PCI,) wherein closure is defined as the time from removal of the catheter to ambulating the patient. More particularly, the invention is concerned with such apparatus and methods which employs a rigid wound-closing body adapted to be placed adjacent and along the length of the wound, together with a force-exerting assembly operable to create forces which generate relatively high pressures on the patient's skin and tissue adjacent the wound. In preferred forms, the rigid body has a three-dimensionally asymmetric lower force-transmitting surface so as to exert forces of different magnitudes at different locations along the force-transmitting surface. Also, the force-transmitting surface is preferably exerted substantially constantly and in a substantially time-invariant manner.
2. Description of the Prior Art
Endovascular interventions such as PCI are widely accepted as a practical treatment option for coronary artery disease. For example, femoral artery puncture is commonly used in endovascular diagnostic and interventional procedures. Alternately, access may be made via the right radial or brachial artery. Such procedures are now commonly performed on an out-patient basis. In the case of a femoral arterial intervention, a puncture wound is made with a cannula to create an oblique subcutaneous tract and a terminal arteriotomy, followed by placement of a sheath within the tract. A catheter is then threaded through the sheath and into the adjacent artery, so that access can be had to the coronary arteries. After the diagnosis or intervention is completed, the catheter is withdrawn, the sheath is removed, and steps must be taken to close the wound. Wound closure typically involves compression to control bleeding until hemostasis occurs. Ideally, wound closure serves to minimize blood loss, effect hemostasis, and render the patient ambulatory in a relatively short period of time.
Poorly executed wound closures may give rise to complications which are costly, increase hospital stays and affect morbidity. For example, inadequate hemostasis can lead to significant blood loss, patient discomfort, vessel occlusion, thrombosis, formation of arteriovenous fistula, and pseudoaneurysm requiring surgical intervention and/or steps to avoid infections. Complications at the access site due to arterial cannulation occur in 1%-5% of cases, but may be as high as 14% with some interventional procedures.
Traditionally, wound closure has been a manual operation where a physician or nurse used manual hand pressure, using either one or two hands. One-handed manual pressure is usually carried out over a period of 30 minutes with a time to ambulation (TTA) of 4-6 hours. Two-handed manual pressure (often referred to as the “gold standard” of wound closure) ideally achieves optimal wound closure. In this technique, the healthcare professional's left hand exerts a semi-occlusive pressure upstream (closer to the heart) of the arteriotomy to moderate blood pressure fluctuations and to reduce the mean blood pressure from the heart without denying blood flow downstream. The professional's right hand holds an occlusive pressure over the arteriotomy, tract, and insertion site. This is continued for a period of approximately 30 minutes. However, in actual practice, there are a number of significant problems. For example, manual pressure that is too firm does not allow sufficient clotting factors to accumulate at the arteriotomy. Moreover, manual pressure along the tract varies because the tips of the four fingers of the right hand are not flat. Even more important, the person exerting manual pressure can tire during the 30-minute holding time, or the fingers may move or may not be placed properly. The person may also temporarily stop the application of pressure to examine the wound, causing a disruption of the maturing clot. Finally, different body types present different manual pressure issues, e.g., if the panniculus intrudes on the person's left hand, pressure variations may be induced as the patient breathes and the panniculus moves. TTA for this two-handed procedure is again normally 4-6 hours.
Manual techniques can be supplemented with use of applied hemostasis adjuncts, which reduce the time to hemostasis (TTH) to 5-6 minutes, but do not lower TTA because there is no force on the arteriotomy after hemostasis is achieved. Manual pressure may also be supplemented with external devices, such as C-clamps or sand bags. These combined techniques have many of the same problems as straightforward manual pressure closures, and the external devices may be difficult to deploy on obese patients. Thus, while manual procedures are of long standing, they are deficient in that they can be tiring, require careful training, and represent inefficient use of the time of valuable medical personnel.
Other closure techniques involve use of an intra-arterial anchor giving a TTH of about five minutes and a TTA of about 2-3 hours. Drawbacks of these procedures include a maximum French size of 8 Fr and the fact that the anchor and collagen plug must be left in the body for up to 90 days. Suture-mediated intra-arterial anchor techniques have also been used, but these are deficient in that the sutures remain in the body until absorbed, and nonetheless require that the anchor and plug be left in the body for an extended period. Finally, intra-tract closure has been used where the arteriotomy is mechanically stretched and then “boomerangs” back to an 18-gauge needle diameter. In these procedures, a heparin-neutralizing drug is deployed within the wound tract, and manual pressure is still required to close the 18-gauge needle hole.
In recent years, new, larger interventional devices of up to 20 Fr are being used to perform tasks like operations within the heart itself. No existing closure device is indicated for these large interventions, and resort must be had to manual pressure or surgical techniques to close the large wounds.
In response to these problems, various specialized vascular closure devices (VCDs) have been proposed, such as the device disclosed in U.S. Pat. No. 5,307,811 and commercialized under the designation “FemoStop.” While these and other VCDs have achieved widespread use, no prior VCD has fully solved the problems inherent in wound closures. Dauerman et al. ( J AM COLL CARDIOLL. 2007; 50 (17) Elsevier Science)—“Vascular Closure Devices: The Second Decade” described an ideal VCD:
The patient factors influencing closure success notwithstanding the “ideal” closure device remains to be developed. What would this device look like? 1) A single device capable of providing successful closure for all patient and success site anatomical variations; 2) an atraumatic device without a foreign body or vascular alteration of the femoral artery; and 3) a simple-to-use device with >95% procedural success and low cost.
The prior art uses the terms “pressure” and “force” loosely. A person exerting force through small fingers would apply more pressure than a person exerting the same force with larger fingers. A further complication is that the heart is beating, making the pressure (sum of internal and external pressure) variable. What is critical is controlling blood flow. If there were no flow restriction, the arteriotomy would leak, resulting in a hematoma. If there were complete flow restriction, then the downstream extremities would be starved of oxygen and the arteriotomy would be starved of necessary clotting factors. Hence, the ideal VCD is one in which flow is restricted, but not excessively.
Accordingly, there is an unfulfilled need in the art for a simple-to-use VCD which closely mimics “gold standard” manual wound closure, has a complication rate of <1%, can be used on all types of patients, gives very low TTH and TTA values, and does not involve residual drugs, sutures, or anchoring devices.
SUMMARY OF THE INVENTION
The present invention overcomes the problems outlined above and provides VCDs and corresponding methods which have many outstanding features. For example, preferred embodiments of the invention used in the context of arterial PCI procedures are characterized by:
a TTA on the order of 60 minutes for diagnostic PCI procedures; a complication rate of <1%; atraumatic, essentially painless wound closure with no residual foreign materials in the wound or vascular alterations; targeted asymmetric tissue pressures, with a larger non-occlusive pressure applied upstream of the arteriotomy to lower the patient's blood flow, with decreasing pressures downstream of the arteriotomy; substantially time-invariant wound closure pressures on the tissue; skin inversion adjacent the wound by means of a Z-stitch suture together with a rigid, force-transmitting surface including a transverse section positioned above the arteriotomy and generating force of greater than about 20 lbs., but not greater than the suture-rupturing force, and an obliquely oriented, axially extending section, which generates decreasing pressures downstream of the arteriotomy; secondary wound closure force through use of an adhesive sheet stretched over the device and adhered to the patient's skin on either side of the site; virtually no blood loss during wound closure; different sheath sizes, blood chemistries (e.g., INR >1.5, or the presence of blood thinners), and degrees of intervention can be accommodated by increasing the closure time; a device cost on the order of $100; wound closure procedure is typically learned with less than ten diagnostic procedures.
In the ensuing description, the methods and apparatus of the invention are described with particular reference to wounds incident to an arterial intervention procedure. However, it should be understood that the invention is equally applicable to other types of vascular vessel procedures where a wound includes an opening in a non-arterial vascular vessel, such as a venous vessel.
In one aspect of the invention, apparatus is provided to close a wound in a patient's tissue where the wound presents an insertion site and an elongated, obliquely oriented tract extending into the patient's tissue and in communication with the insertion site. Such apparatus comprises a body having an elongated, rigid force-transmitting surface and operable to be placed in an external wound-closing position with the force-transmitting surface proximal to the patient's skin, adjacent the wound and in general axial alignment with the tract. A force-exerting assembly is coupled with the body and is operable to exert forces of different magnitudes at different locations along the length of the force-transmitting surface in order to close the wound. In preferred forms, the force-transmitting surface is three-dimensionally asymmetric, and comprises first and second, preferably coplanar, surface sections having different force-transmitting areas respectively. Also, a third force-transmitting surface is provided which bridges the first and second surface sections and is generally T-shaped in configuration, presenting an elongated segment and a segment transverse to the elongated segment. Desirably, the elongated segment is obliquely oriented relative to the first and second surface sections. The force-exerting assembly is operable to exert a force which generates a force on the tissue of at least about 10 lbs., and more preferably at least about 20 lbs.
The overall force-exerting assembly also includes structure for securing the body to the patient's tissue, and a mechanism including a shiftable component for generating a mechanically-derived force through the force-transmitting surface. Such securement structure preferably comprises a suture passing through the patient's tissue and tied to the body to hold the body in the wound-closing position. The suture may be in the form of a known Z-stitch suture which serves to invert the patient's skin at the wound site. The mechanism is preferably in the form of a biasing structure including at least one (and more preferably two) spring(s). Secondary forces may be generated by means of an adhesive sheet stretched over the device and adhered to the patient's skin on opposite sides of the wound site.
Advantageously, the force-exerting assembly is designed to exert a substantially constant and time-invariant force through the force-transmitting surface; this, coupled with the preferred asymmetric force application serves to reduce the patient's blood pressure and flow within the artery and especially at the arteriotomy.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded, upper perspective view of the preferred wound-closing apparatus of the invention;
FIG. 2 is an exploded, lower perspective view of the preferred wound-closing apparatus of the invention;
FIG. 3 is a side elevational view of the fully assembled apparatus;
FIG. 4 is an end view of the fully assembled apparatus;
FIG. 5 is a side view in partial vertical section illustrating the base portion of the apparatus, with the force-exerting springs in the released position thereof;
FIG. 6 is a vertical sectional view taken along the line 6 - 6 of FIG. 5 ;
FIG. 7 is a vertical sectional view taken along the line 7 - 7 of FIG. 5 ;
FIG. 8 is a side view in partial vertical section illustrating the base portion of the apparatus, with the force-exerting springs in the cocked position thereof;
FIG. 9 is a vertical section view taken along the 9 - 9 of FIG. 8 ;
FIG. 10 is a vertical section view taken along the line 10 - 10 of FIG. 3 ;
FIG. 11 is a top view illustrating a catheter sheath positioned within a wound attendant to a vascular procedure, and further illustrating the first step in the preferred method of the invention wherein a Z-shaped stitch has been created with a suture in the patient's tissue;
FIG. 12 is a sectional view of the wound, sheath, and suture depicted in FIG. 11 ;
FIG. 13 is a top view illustrating the next step in the preferred method wherein the ends of the suture are tied to define an X-shaped stitch over the patient's skin;
FIG. 14 is an end view in partial section illustrating the next step in the preferred method wherein the X-shaped stitch is tightened to invert the patient's skin adjacent the wound opening and the base of the apparatus is pressed downwardly over the stitch and wound opening;
FIG. 15 is a sectional view of the steps depicted in FIG. 14 ;
FIG. 16 is a top view of the steps illustrated in FIGS. 14 and 15 , with the apparatus base illustrated in phantom and also showing withdrawal of the catheter sheath from the wound tract;
FIG. 17 is a top view of the next step of the method wherein the ends of the suture are passed around the rotatable operator forming a part of the apparatus base and knotted;
FIG. 18 is a sectional view illustrating the position of the apparatus base and operator after the tying and knotting step illustrated in FIG. 17 ;
FIG. 19 is a view similar to that of FIG. 18 , but illustrating the operator rotated to allow the force-exerting springs of the base to move from the cocked to the released position thereof so as to close the wound tract and reduce blood flow through the patient's artery adjacent the wound arteriotomy;
FIG. 20 is a side view of the installed apparatus with a cover secured to the base and with a stretch of adhesive passed over the cover and secured to the patient's tissue on opposite sides of the wound and apparatus;
FIG. 21 is a vertical sectional view of the fully installed apparatus illustrated in FIG. 20 ;
FIG. 22 is a top view of a preferred additional method step wherein a dam is placed around the wound opening and the sheath, and a hemostatic powder is deposited within the confines of the dam and over the wound opening; and
FIG. 23 is a top view of the condition of the patient's tissue after wound closure and with the patient ambulatory.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The Preferred Wound Closure Apparatus
Turning now to the drawings, apparatus 30 operable to close a wound in a patient's tissue is illustrated in FIGS. 1-4 . The apparatus 30 is particularly designed for closure of wounds attendant to an endovascular (i.e., arterial or venous) intervention involving, e.g., a femoral artery puncture where the wound presents an insertion site, an elongated, obliquely oriented tract extending into the patient's tissue and communicating with the insertion site and an arteriotomy. Broadly speaking, the apparatus 30 includes a force-transmitting body 32 having a force-exerting assembly 34 together with a removable cover or “hat” 36 .
As used herein, terms such as “upper” and “lower,” “top and “bottom,” and “downwardly” and “upwardly” and the like are used for convenience and because of the fact that the apparatus 30 is normally positioned in an upright orientation on a patient with the cover 36 being directly above the body 32 . However, if the apparatus 30 were to be placed in a different orientation (e.g., sideways) the cover 36 would nonetheless be deemed to be above the body 32 , and the above terms are intended to embrace all such different orientations.
In more detail, the body 32 is of rigid unitary construction and is formed of an appropriate synthetic resin material. The body 32 has first and second, axially aligned cup-like sections 38 and 40 , each with an arcuate, upstanding sidewall 42 , 44 , a bifurcated, rectilinear end wall 46 , 48 , and a bottom wall 50 , 52 serving to interconnect the section 38 , 40 . A pair of grooves 54 and 56 are provided between each of the end wall bifurcations as best seen in FIG. 2 . The bottom walls 50 , 52 are configured to present first and second substantially flat and coplanar force-transmitting sections 58 and 60 ; it will be observed that the area of section 58 is smaller than that of section 60 , and this is important for purposes to be described.
A protruding, downwardly extending segment 62 bridges and is integral with the bottom walls 50 , 52 and presents a lowermost, generally T-shaped third force-transmitting surface 64 which bridges the sections 38 and 40 . The surface 64 presents an elongated, obliquely oriented and progressively tapered segment 66 extending from the end of bottom wall 52 to a point below bottom wall 50 . Another surface segment 68 is generally transverse to the elongated segment 66 and is substantially centrally located below bottom wall 50 . The segment 62 further includes a generally U-shaped sidewall 70 extending downwardly from the bottom walls 50 , 52 of the sections 38 , 40 .
It will be appreciated that the body 32 presents an overall force-transmitting surface 72 made up of the force-transmitting sections 58 , 60 , 64 , and 68 . This surface 72 is three-dimensionally asymmetric owing to the fact that the area of first surface section 58 is less than that of the second surface section 60 (so that the overall surface 72 is asymmetric in a fore-and-aft direction), and because of the fact that the inclined surface segment 66 and transverse surface segment 68 are positioned below the first and second sections 58 , 60 (so that the overall surface 72 is asymmetric in a vertical direction). Moreover, the inclined segment 66 provides an increasing and progressive force gradient from the second surface section 60 to the transverse segment 68 .
The sections 38 and 40 are each equipped with an upstanding, slotted, tubular member 74 or 76 which extend upwardly from the upper surfaces of the corresponding bottom walls 50 , 52 . As best seen in FIGS. 5 and 8 , an elongated, downwardly extending cylindrical opening 78 is formed in bottom wall 50 and protruding segment 62 directly beneath and coaxial with the tubular member 74 . Likewise, a shorter, downwardly extending cylindrical opening 80 is provided directly beneath and coaxial with tubular member 76 . Each of the openings 78 , 80 has a plurality of elongated, upright, circumferentially spaced apart, inwardly extending, integral ribs 82 .
The configuration of the tubular members 74 , 76 is identical, and therefore only the construction of member 74 will be described in detail. Specifically, member 74 has an upstanding sidewall 84 with a pair of specially configured and opposed slots 86 formed therein. The sidewall 84 is reinforced by means of external gussets 88 and braces 90 . Each slot 86 includes a lowermost, substantially frusto-circular portion 92 , an intermediate upright portion 94 , and an uppermost, inwardly extending lip portion 96 .
The force-exerting assembly 34 generally includes a pair of identical, helically coiled springs 98 , 100 respectively housed within a corresponding tubular member 74 , 76 and supported therein by means of the adjacent upstanding ribs 82 . The overall assembly 34 further includes an elongated, axially rotatable paddle-like operator 102 , which extends fore and aft and is received by the opposed slots 86 , so that the operator extends through and is supported by both of the tubular members 74 , 76 and engages the springs 98 , 100 . The operator 102 is likewise formed of synthetic resin material and includes a central segment 104 , a pair of identical, elongated, slotted, oval-shaped segments 106 and 108 on opposite sides of the central segment 104 , and fore-and-aft segments 110 , 112 .
Referring to FIG. 5 , it will be observed that the central segment 104 is cylindrical in configuration and has a central, peripheral, suture-receiving groove 114 formed therein. The oval segments 106 , 108 are situated within the tubular members 74 , 76 and have major axes 116 and transverse, minor axes 118 ( FIG. 6 ). The fore end segment 110 has a rounded outer edge, whereas the corresponding aft end segment 112 has a recessed trailing edge. In this fashion, the operator 102 has an arrow-like shape along the length thereof.
The operator 102 serves to allow selective compression of the springs 98 , 100 so as to maintain the springs in a cocked position as best seen in FIGS. 8 and 9 . Upon 90° rotation of operator 102 , the springs 98 , 100 are released to a force-exerting position illustrated in FIGS. 5-7 and 10 . In more detail, if it is desired to cock the springs 98 , 100 , the operator 102 , in the FIG. 5-7 position where the major axes 116 are upright, is pressed downwardly through the upright portions 94 of the slots 86 until the bottom peripheries of the oval segments 106 , 108 engage the bottoms of the frusto-circular portions 92 . Thereupon, the operator 102 is rotated 90° in either direction so that the major axes 116 are substantially horizontal and the oval segments 106 , 108 are captively retained by the frusto-circular portions 92 . When it is desired to release the springs 98 , 100 , this operation is reversed, i.e., the operator 102 is rotated 90° until the major axes are again upright. The springs 98 , 100 then urge the operator 102 upwardly to the FIGS. 5-7 position, with the lip portions 96 of the slots 86 serving to retain the operator 102 within the slots 86 .
The cover 36 includes an uppermost wall 120 which is gently arcuate in cross-section and presents an upper surface 122 and a lower surface 124 . A pair of depending, slotted tubular members 126 , 128 extend from bottom surface 124 and are in alignment with the tubular members 74 , 76 . The members 126 , 128 are identical, and therefore only member 126 will be described in detail. As best seen in FIGS. 1 , 2 , and 4 , the member 126 includes a sidewall 130 with a pair of opposed slots 132 . Each slot 132 includes an uppermost arcuate portion 134 and a substantially rectilinear portion 136 . The tubular members 126 , 128 are of slightly larger diameter than the corresponding tubular members 74 , 76 , allowing the cover 36 to be positioned over body 32 and pressed downwardly over the tubular members 74 , 76 to assume the position depicted in FIGS. 3-4 . It will be observed in this respect that the slots 86 of the tubular members 74 , 76 are in substantial alignment with the slots 132 of the tubular members 126 , 128 .
Preferred Method of Use of the Wound Closure Apparatus
The preferred method of using the apparatus 30 is depicted in FIGS. 11-23 , in the context of the closure of a femoral artery puncture wound 138 ( FIG. 12 ). It is to be understood, however, that the ensuing discussion is exemplary only, and that the invention can be used in virtually every type of endovascular arterial or venous intervention.
The wound 138 is in the groin tissue 140 of a patient and includes an insertion site 142 , an elongated, obliquely extending tract 144 extending from insertion site 142 and terminating at an arteriotomy 146 in the femoral artery 148 . A conventional catheter sheath 150 is positioned within the tract 144 in order to permit an endovascular procedure using a catheter (not shown). When the procedure is completed and the catheter removed, it is necessary to promptly close the wound 138 during removal of the sheath 150 , while minimizing any blood loss and rendering the patient ambulatory in as short a period as possible.
In order to facilitate the description of the preferred wound closure technique, the direction towards the patient's heart is denominated as “north,” whereas the direction leading away from the heart is denominated “south.” Correspondingly, transverse directions are denominated as “east” and “west,” respectively. Accordingly, it will be observed that the tract 144 extends from the insertion site 142 to the arteriotomy 146 in a generally northerly direction.
In the first step of the wound closure procedure, the endovascular physician creates a Z-stitch 154 ( FIGS. 11-12 ) in the patient's tissue 140 by passing a suture 156 through an entrance 158 east of the artery 148 and south of insertion site 142 , an exit 160 west of artery 148 and south of insertion site 142 , an entrance 162 north of insertion site 142 and east of artery 148 , and finally an exit 164 . The end of the suture 156 adjacent entrance 158 is then clipped. The stitch 154 thus includes exterior suture stretches 166 and 168 , embedded suture stretches 170 and 172 above artery 148 at a depth of less than about one-half inch, and an obliquely extending exterior stretch 174 extending between the exit 160 and entrance 162 .
In the next step ( FIG. 13 ), the exterior suture stretches 166 and 168 are crossed and interconnected by folding the stretches over each other, thereby creating an X-stitch 176 with a central suture fold 178 , and with the free ends 166 a , 168 a of the exterior suture stretches 166 , 168 extending westerly and easterly, respectively. Preferably, the suture fold 178 is positioned in very close proximity or over the insertion site 142 .
The next step ( FIGS. 14-18 ) requires two health care providers and generally involves tightening of the X-stitch 176 while the force-transmitting body 32 of apparatus 30 is positioned atop wound 138 with application of a downwardly directed force, and the sheath 150 is removed. In detail, one care provider grasps the free suture ends 166 a , and 168 a , and pulls these in an easterly and westerly direction, respectively. This serves to tighten the suture while inverting the patient's skin tissue, as illustrated by numeral 180 , at the region of the insertion site 142 . That is, uninvolved, parallel peripheral tissue is forced upwardly, while the central tissue adjacent the wound is pushed downwardly over the entire insertion site 142 , tract 144 , and arteriotomy 146 . The inverted tissue in cross-section thus resembles an M in shape.
Once the skin is inverted, the second provider presses body 32 (which is in the spring-cocked position thereof) downwardly into the patient's tissue 140 , while withdrawing the sheath 150 . In particular, the body 32 is located in general north-south alignment with the artery 148 , such that the force-transmitting surface sections 58 and 68 are above and north of insertion site 142 and arteriotomy 146 , with the oblique section 64 over the suture fold 178 , and with the rearmost portion of surface section 60 located south of the insertion site 142 . As the body 32 is held in this position, the first provider, while still maintaining tension on the suture free ends 166 a and 168 a , pulls the ends upwardly through the body grooves 54 and over the central segment 104 of operator 102 , and forms a secure knot 182 at the top surface of the segment 104 . In this condition (see FIGS. 17-18 ) the artery upstream of arteriotomy 146 is partially closed, whereas tract 144 and arteriotomy 146 are fully closed.
In preferred practice, the suture ends 166 a , 168 a are pulled upwardly while avoiding any twisting prior to formation of the knot 182 . This avoids reduction in the burst strength of the suture ends. That is, if the ends are twisted prior to knotting, the burst strength of the suture ends is reduced and can induce premature failure of apparatus 30 .
In order to establish and maintain a substantially constant and time-invariant wound closure force, the operator 102 is rotated 90° so that the springs 98 , 100 are released to their force-exerting positions ( FIGS. 5-7 and 19 ). This serves to maintain the suture 156 in tension so as to firmly draw the body 32 into the wound-closure position while also maintaining a substantially even force based upon the strengths of the springs 98 , 100 . Preferably, the tensile force exerted on the suture 156 is slightly below the burst strength thereof; thus, the tensile force on suture 156 should typically be 10-15% less than the suture burst strength.
Next, the cover 36 is positioned atop body 32 by pressing the tubular members 126 , 128 over the tubular member 74 , 76 until the cover is firmly seated. At this point, a length of wide adhesive material 184 (e.g., 6×8 inches) is placed over the cover 36 with the ends of the material 184 being pulled downwardly and adhesively attached to the patient's tissue at east and west and north and south locations, respectively. This material 184 may be stretchable or non-stretchable, and if desired may be breathable. Placement of the material 184 serves to exert a secondary force through the body 32 , in addition to that exerted by the springs 98 , 100 , while also stabilizing the apparatus 30 on the patient. Advantageously, the height of the apparatus 30 above insertion site 142 divided by the maximum east-west transverse dimension of the force-transmitting surface 72 is greater than 1. With this ratio, the vertical component of the force generated by the material 184 is increased, causing additional force to be applied over the entirety of the wound.
As finally positioned, the apparatus 30 creates targeted, asymmetric tissue pressures from north to south. At the north, a larger, non-occlusive pressure is applied upstream of the arteriotomy 146 in order to lower the patient's blood pressure and blood flow at the downstream arteriotomy. The transverse surface segment 68 , positioned directly above the arteriotomy 146 , closely mimics a properly executed two-handed manual wound closure. The lesser tissue pressures created south of the arteriotomy 146 , owing to the decreasing force gradient generated through the oblique section 66 , and the greater surface area of southernmost section 60 , also are similar to such manual closure.
FIG. 22 depicts another preferred aspect of the invention, namely the use of a compressible dam 186 having a central opening 188 over the wound. In particular, the dam is placed in surrounding relationship to the insertion site 142 and a hemostatic powder 190 is sprinkled into the opening 188 (about 0.3 g). This procedure is carried out prior to tensioning of the suture free ends 166 a , 168 a , and placement of the apparatus 30 on the wound site, as previously described. Of course, the dam remains in place during the entire closure sequence, and is then removed after closure. The hemostatic powder 190 may be a cationic surfactant combined with a strong acid cation exchange resin, or a potassium ferrate/strong acid cation exchange resin. Preferably, the powder 190 is of the type described in U.S. Pat. No. 6,187,347. In another embodiment, a sheet of exudate-absorbing woven or non-woven hemostatic material (such as oxidized cellulose or chitosan) may be used in lieu of or in addition to the powder 190 .
FIG. 23 illustrates the condition of the wound 138 at the completion of wound closure. After the appropriate closure time, the knotted suture 156 is cut and the apparatus 30 is removed from the wound 138 . It will be seen that the insertion site 142 is closed (clotted) with the suture openings likewise closed. If desired or needed, a hemostatic/antiseptic powder can be sprinkled over the insertion site and the suture openings to help prevent infections and inhibit oozing. Normally, no dressing is required, and the loose powder is merely brushed off the wound site.
A significant advantage of the invention is that TTAs are substantially reduced. In the case of diagnostic procedures, TTAs on the order of 60 minutes are common, and with more complex interventional procedures, TTAs of 120 minutes are typical. In a pre-clinical study involving 100 patients with interventional procedures up to 12 Fr, the preferred apparatus of the invention closed the patients' wounds with no complications and TTAs of less than 120 minutes
The invention also is useful with seriously obese patients. With such patients, the panniculus descends to the femoral insertion site, interfering with normal deployment of closure devices. This restricts the space around the wound and the ability of the healthcare professional to properly apply manual closure pressure. However, in the present invention, pre-compression of the springs 98 , 100 and latching them with the operator 102 allows the device to be aligned over the wound and the knot 182 tied. Thereupon, the operator 102 is rotated to release the springs, and the material 184 is applied.
Those skilled in the art will appreciate that the preferred embodiment of the invention may be modified in many ways while still achieving the aims of the invention. For example, while identical springs 98 , 100 are preferred, springs of different strengths and/or types may be used, e.g., flat and coiled springs. The springs may be attached to the lower body or the top cover of the apparatus, at the discretion of the designer. Additionally, the invention may be practiced without the use of the Z-stitch suture 156 . In this embodiment, a spring force is generated directly against the top cover by manually placing the cover in direct contact with the spring(s). Then an adhesive material or film 184 is brought over the cover and pressed downwardly to compress the spring(s) and hold the device in place by adhering the film to the patient's skin on either side of the wound 138 . Such an embodiment is useful, for example, on very thin elderly patients whose skin is so fragile that sutures are not effective to retain the device in place.
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Wound closure apparatus is provided including a body having an elongated, lowermost force-transmitting surface operable to be placed in a proximal, external, wound-closing position on a patient, together with a force-exerting assembly coupled with the body and operable to exert a downwardly directed force serving to generate wound-closing pressure against the patient's tissue. The force-transmitting surface is preferably three-dimensionally asymmetric so that forces of different magnitude are exerted at different locations along the length of the surface. The apparatus is especially designed for the closure of wounds attendant to endovascular interventions, e.g., a femoral artery puncture wound incident to percutaneous cardiac intervention (PCI), and is capable of quickly effecting wound closure with a time-to-ambulation (TTA) of approximately 60 minutes, and with a very low complication rate.
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BACKGROUND OF THE INVENTION
This invention relates to a hammer of the valveless pneumatic type which is generally used for "down-the-hole" drilling.
These hammers normally comprise a hollow casing with an operatively upper and a lower end, and, which has a piston therein which reciprocates between an upper and a lower pressure chamber, and also has a bit assembly at the lower casing end and a backhead assembly at the upper casing end.
The design of such hammers usually provides for additional upper chamber space above the piston in order to prevent the pressure from rising too high when the volume decreases owing to the piston's upward movement. This space increases the volume of the upper chamber and in the conventional design results in an increase in the overall hammer length.
The outside diameter of typical hammers is usually restricted owing to the size hole that they are designed to drill, and thus there is difficulty in fitting the largest possible diameter piston inside the bore of the hammer, which is desirable in order to obtain more effective piston impact on the bit assembly. The largest diameter piston possible which could fit in the hammer, is of course a piston having a diameter marginally smaller than the inside diameter of the threaded ends of the casing. It is usually not possible to fit that piston of this size however, as a shoulder has to be provided to locate the chamber divider on the inner end thereof in the casing. This same restriction applies to the bit assembly, as a guide is usually located at the other end of the casing to secure the bit assembly.
It is an object of this invention to provide a valveless pneumatic hammer which has features which alleviate the above-mentioned problems.
SUMMARY OF THE INVENTION
In accordance with this invention there is provided a valveless pneumatic hammer comprising:
a hollow casing;
a backhead assembly at one end of the casing;
a bit assembly at the other end of the casing, having a rod extending into the casing and having a passage into the rod end and passing out to atmosphere at the other end of the assembly;
a chamber divider in the backhead end of the casing having a control rod projecting into the casing, the innermost end of the divider being adapted to seal against a piston bore during a portion of piston movement in use;
a piston having a large bore in one end and a smaller concentric bore through the other end into the larger bore, the larger bore end being adapted to co-operate with the chamber divider end for the sealing of the larger bore, the piston being further adapted to reciprocate between two positions, the first position being with the smaller bore end against the bit assembly where the bit assembly rod within and sealing off the smaller bore and the larger piston bore sealed off by the chamber divider end, and the second position being with the piston displaced towards the backhead assembly, the larger bore unsealed and the chamber divider control rod within and sealing off the smaller bore, and with the bit assembly rod removed from the smaller bore;
a first chamber with the piston in the first position, formed around a bit assembly portion extending into the casing from a stepped portion of the casing;
a second chamber with the piston in the second position, formed by the larger bore of the piston and the annular recess in the chamber divider;
a first fluid supply path through the backhead assembly, between the chamber divider walls and the casing wall, into at least one passage in the casing wall opposite the piston in the first piston position and into the first chamber;
a second fluid supply path through the backhead assembly, between the chamber divider walls and casing wall, between the unsealed chamber and piston ends in the second position of the piston and into the second chamber;
a first fluid exhaust path from the first chamber into the bit assembly passage with the piston in the second position and out into atmosphere; and,
a second fluid exhaust path from the second chamber through the smaller piston bore with the piston in its first position, into the bit assembly passage and out to atmosphere.
Further features of the invention provide for the end portion of the larger bore of the piston to be stepped inwardly, and for the inner end portion of the chamber divider to be stepped outwardly, and for the two stepped portions to co-operate for sealing off the larger bore by the sliding movement of the chamber divider within the larger piston bore.
There is provided for the chamber divider to be located within the casing by a split locating ring concentrically fitted within an annular concentric recess in the casing, the depth of the recess being less than or equal to the depth of the internal screw threading in the casing.
The chamber divider preferably has a stepped portion therein which engages with the split locating ring. The backhead end of the chamber divider is adapted to co-operate with the inner end of the back-head assembly for the securing of the chamber divider between the screwed in backhead assembly, and the locating ring.
Further, the depth of the passages in the casing walls making up the fluid supply path, are also preferably not deeper than the depth of the internal screw threading of the casing ends.
There is also provided for the control rod of the chamber divider to have a passage therethrough communicating with a pressure valve at the backhead end in order to increase the air flow through the hammer should the hammer be used at lower pressures, which cause an insufficient flow of air through the hammer. The valve 12 is adapted to open when the operating fluid for the assembly is below a predetermined level.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention is described below by way of example, and with reference to the accompanying sketches in which:
FIG. 1 is a cross-sectional view of a valveless pneumatic hammer with piston in a first position;
FIG. 2 is an enlarged cross-sectional view of a section of the hammer of FIG. 1; and
FIG. 3 is a cross-sectional view of a valveless pneumatic hammer with piston in a second position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A hollow casing 1 has a backhead assembly 2 at one end thereof, and a bit assembly 3 at the other end.
The backhead assembly 2 is secured in the casing 1 end by internal screw-threading 4 in the casing. A chamber divider 5 is located in the casing 1 between a split locating ring 6 and the inner end 7 of the back-head assembly 2. This chamber divider 5 has an outwardly stepped portion 8 at the end thereof remote from the back-head assembly 2, and a central control rod 9 projecting from this end. An annular recess 10 is located in this end around the central control rod 9. A central bore 11 extends through the control rod 9 from end to end to a pressure valve assembly 12 in the backhead assembly 2.
A piston 13 has a large bore 14 in one end thereof and a smaller bore 15 in the other end thereof, which extends through to the larger bore 14. The large bore end of the piston 13 has an inwardly stepped section 16, which is slidable in an airtight manner over the outer surface of the outwardly stepped section 8 of the chamber divider 5.
The bit assembly 3 has a shaft 17 which has a protruding rod 18 extending into the chamber. The assembly 3 is slidable within the casing 1 between predetermined limits. This degree of slide is achieved, and the assembly 3 is located within the casing 1, in any suitable manner. A portion of the shaft 17 extends into the casing 1 interior from a stepped section of the casing 1, and the degree of slide of the bit assembly 3 allows it to move between a raised position in which the shaft 17 portion is in the casing 1 interior and a lowered position where the bit assembly 3 end is flush with the stepped section of the casing 1.
A passageway 19 passes through the end of the projecting rod 18 through to the atmosphere out of the bottom of the bit assembly 3. This passage 19 divides into two separate passages 20 in the outer portion of the bit assembly 3 and these passages 20 communicate with atmosphere at the side of the bit assembly 3.
Two annular recesses 21 are located in the casing 1, one near each end of the interior of the casing 1. The piston 13 has a central stepped annular recess 22, of approximately the same width as the distance between the recesses 21 in the casing 1.
The piston 13 is adapted to reciprocate between two positions. The first position (FIG. 1) is with the piston 13 against the bit assembly 3 in its raised condition, and with the bit assembly rod 18 extending fully into the small bore 15 of the piston 13. In this position a first chamber 23 is formed around the bit assembly 3 and is defined by the wall of the bit assembly 3 at this position, the casing wall opposite it, the stepped portion 24 of the bit assembly 3 and the overlapping portion 25 of the piston 13.
Further in this position the end region of the recess 21 nearest the bit assembly 3 communicates with the first chamber 23 and the other recess 21 communicates with the casing 1 interior just past the large bore 14 end of the piston 13. The inwardly stepped portions of the piston 13 and chamber the divider 5 are axially aligned and seal off the large bore 14 of the piston 13, and the annular recess 10 of the second chamber 26, from the interior of the casing 1.
In the second position of piston 13 movement (FIG. 3) the piston 13 is displaced towards the backhead assembly 2, the small bore 15 end of the piston 13 is removed from the projecting rod 18 of the bit assembly 3, and the inwardly stepped section 16 of the piston 13 has now slid past the outwardly stepped portion 8 of the chamber divider 5, as illustrated. In this position the control rod 9 of the chamber divider 5 is within the small bore 15 of the piston, and the backhead recess 21 is sealed off from the interior of the casing 1 by the piston 13 wall. At the small bore 15 end, the projecting rod 18 is removed from the bore of the piston 13. A second chamber 26 is formed with the piston 13 in this position and is defined by the large bore 14 of the piston 13 and the recess 10 in the chamber divider 5.
A first fluid supply path starts through the backhead assembly 2 past the chamber divider 5 and the casing walls into the recess 21 at the backhead 2 end, with the piston 13 in its first position, and then between the casing 1 and the recess 22 in the piston 13, into the casing recess 21 at the bit assembly 3 end, and into the first chamber 23. This first fluid supply path is clearly indicated by the arrows 27 in FIG. 1 of the drawings.
A second fluid exhaust path from the second chamber 26 passes from the chamber 26 into the small bore 15 of the piston 13 from there into the passage 19 in the bit assembly 3 and out to the atmosphere. This exhaust path is indicated by arrows 28 in FIG. 1.
A second fluid supply path, with the piston 13 in its second position (FIG. 3), passes through the backhead assembly 2 between the chamber divider 5 and casing wall and between the inner wall of the large bore 14 of the piston 13 and the outer wall of the chamber divider 5 into the second chamber 26. This path is clearly indicated by arrows 29 in FIG. 3.
A first fluid exhaust path passes from the first chamber 23, with the piston 13 in its second position, directly into the passage 19 in the bit assembly 3 and through this passage out to the atmosphere. This exhaust path is indicated by arrows 30 in FIG. 3.
A radial opening 31 through the wall of the chamber divider 5 is located at the outwardly stepped portion 8 thereof. The opening 31 is positioned so that it communicates between the second fluid chamber 26 and the passage between the chamber divider 5 and the casing 1 wall when the inwardly stepped section 16 of the piston 13 is on the bit assembly 3 side of the opening 31.
In use, air under pressure is admitted to the casing 1 by the backhead assembly 2 and passes along the first fluid path into the first fluid chamber 23 where the pressure causes the piston 13 to move towards the backhead assembly 2 and position two. Clearly the end piston surface exposed to pressure in chamber 23 has a larger area than the end surface of the piston 13 at the large bore 14 end.
As the piston 13 moves towards its second position the rod 18 is removed from the second chamber 26 and air from the second chamber 26 follows the first fluid exhaust path.
The piston moves towards its second position and the entrance to the grooves at the backhead 2 end is closed off by the piston 13 moving over it and the second fluid supply path is opened by the inwardly stepped section 16 of the piston 13 moving past the outwardly stepped section 8 of the chamber divider 5. A second fluid supply path is thus open, and air follows this path into the second chamber 26.
The pressure in this second chamber 26 causes the piston 13 to commence moving back towards the bit assembly 3. Once the piston 13 has moved sufficiently far for the projecting central control rod 9 of the chamber divider 5 to be removed from the small bore 15 of the piston, the second fluid exhaust path is now open, and air from the second chamber 26 exhausts along this path out to the atmosphere.
It will be appreciated that the recess 10 increases the volume of the second chamber 26 and thus reduces a build up of pressure caused by the piston 13 returning to its second position. This effect is achieved without increasing the overall length of the hammer and represents thus a saving in materials and allows for easier manueverability of the hammer.
Further, air following both of the fluid exhaust paths passes through the bit assembly 3 and thus serves to remove drilling material from the borehole that may have lodged therein.
The location of the chamber divider 5 by means of the locating split ring 6 allows a piston 13 of the maximum diameter to be used and thus the maximum effect of impact of the piston 13 against the bit assembly 3 is achieved. Preferably the depth of the recesses 21 is also not greater than the depth of the internal screw threading 4 of the backhead 2 end.
If the casing 1 is raised off the surface being drilled, the bit assembly 3 drops to its lower position with the piston 13 resting thereon. In this position, the end of the stepped portion 16 of the piston 13 uncovers the opening 31, which communicates between the second chamber 26 and the passage between the casing 1 wall and the chamber divider 5. Air thus follows the path between the casing 1 wall and the chamber divider 5, through the opening 31 and into the second chamber 26 and out along the exhaust path 28 to the atmosphere through the bit assembly 3. This allows for continuous flushing of the borehole and the bit assembly 3, and since all the air supply being supplied to the machine is exhausted as described, the machine is inactive in this condition.
It is considered that the invention provides an effective pneumatic hammer which alleviates difficulties experienced in prior art hammers of the same type.
Variations may be made to the above embodiment without departing from the scope of the invention. For example, the first fluid supply path may pass through a passage or passages which are located entirely in the casing 1 wall, and the piston 13 need not have recesses at all in its outer wall.
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A valveless pneumatic hammer comprises a hollow casing having a backhead assembly at one end and a bit assembly at the other, and a piston reciprocable in the casing. There is a chamber divider at the backhead end of the casing which co-operates with the piston for conducting fluid under pressure into alternate chambers, one at each piston end, for reciprocation of the piston. A chamber divider is located within the casing by a locating split ring which holds the chamber divider axially against the backhead assembly. The chamber divider also has a recess in the end thereof nearest the piston which together with a bore in this piston end, comprises the fluid chamber at this end of the casing.
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RELATED APPLICATION
[0001] This application is a divisional of application Ser. No. 10/455,069, filed Jun. 5, 2003, incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The field of the invention is wastewater cleaning systems, and more particularly systems for removing debris and other materials from wastewater.
BACKGROUND
[0003] Systems are needed for the removal of unwanted material from wastewater and other fluids. For example, bar screens are often used to protect a wastewater plant or pumping station against the entry of large objects that are likely to cause blockage in different parts of the installation, and to separate and extract bulky matter carried in the raw influent that is likely to interfere with subsequent operation or to create complications in the treatment process.
[0004] Screening is typically performed either with manually-cleaned bar screens or (when the plant is sufficiently large) with an automatically-cleaned bar screen system called a mechanical bar screen. These bar screen systems are typically installed in a fluid channel prior to entry of the influent to the treatment system to physically remove debris from the fluid as it travels along the channel.
[0005] These systems may utilize a hoist rope, pin rack or other such system to which a rake is attached. The bar screen extends down from the rack into the fluid channel to collect the debris. An electric motor, and possibly a hydraulic fluid pump, is typically used to drive the rake, forcing it down into the fluid, where it scoops up debris, dragging it up along the bar screen and up to a discharge apron, where the debris falls into a disposal unit, such as a cart or other conveyor.
[0006] During this process, the flow of the fluid through the channel does not need to be interrupted, and continues to flow during the cleaning process. While the mechanical bar screen normally operates at predetermined speed based upon the flow rate of the influent, systems are also known that may operate at two predetermined speeds; one for the off-peak flow rate and one for the peak flow rate. The system may be switched between these two speeds by the operator.
[0007] However, such systems cannot be adaptively controlled to account for ongoing variations in the flow rate of the fluid through the channel, and therefore cannot operate at maximum efficiency when fluctuations in flow rate occur. A system is therefore needed that improves upon these other designs.
SUMMARY OF THE INVENTION
[0008] Embodiments of the invention may include a system for removing waste material from a fluid flowing in a channel. This system may incorporate the use of a trap for collecting the waste material while allowing the fluid to pass; a rake for removing the waste material away from the rack; a drive assembly for moving the rake to remove the waste material; a prime mover for operating the drive assembly; and a variable speed controller configured for operating the prime mover over a variable range of speeds.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing and other aspects and advantages will be better understood from the following detailed description of the invention with reference to the drawings, in which:
[0010] FIG. 1 illustrates a mechanical bar screen system.
[0011] FIG. 2 illustrates a hydraulic mechanical bar screen system.
[0012] FIG. 3 illustrates an electrical mechanical bar screen system.
DETAILED DESCRIPTION
[0013] The invention will be understood more fully from the detailed description given below and from the accompanying drawings of the preferred embodiments of the invention; which, however, should not be taken to limit the invention to a specific embodiment, but are for explanation and understanding only.
[0014] FIG. 1 illustrates a mechanical bar screen system. Fluid channel 100 contains the influent, which is flowing at a given flow rate through the channel. The flow rate of this fluid may periodically vary due not only to predetermined peak and off peak flow rates, but also to changes in demand or other conditions that may vary the flow rate in a manner that has not previously been determined. Trap 102 may extend down into fluid channel 100 , trapping debris against it as the influent flows past. Those of ordinary skill in the art will appreciate that trap 102 may comprise any mechanism for collecting the debris, such as a wire screen, mesh, grating, porous material, etc. Trap 102 may be attached directly to fluid channel 100 , although the invention is not limited thereto.
[0015] Rake 104 is shown in an extended position as it prepares to remove the debris collected on trap 102 . Rake 104 may be operated by drive assembly 106 , which is connected to hoist 120 . In this embodiment, hoist 120 may be a pin rack and drive assembly 106 contains a cogwheel operating on the pin rack, although any mechanism capable of moving drive assembly 106 may be used, such as a rope and pulleys, etc. Hoist 120 drive assembly 106 may be operated by prime mover 108 . Prime mover 108 may comprise any mechanism capable of moving driving assembly 106 , such as an electric motor, a hydraulic motor, etc. Prime mover maybe located on drive assembly 106 , or may be located separately. The invention is not limited.
[0016] This may be accomplished in any conventional manner. For example, prime mover 108 may circle drive assembly 106 around hoist 120 within frame 116 ; causing drive assembly 106 , to move downward to the bottom of frame 116 , around, and then back up; repeating this process as necessary. The movement of drive assembly 106 , forces rake 104 down to the bottom of fluid channel 100 and up along bar screen 102 .
[0017] Drive assembly 106 is preferably configured so that rake 104 is extended out away from bar screen 102 as it is lowered into fluid channel 100 . For example, drive assembly 106 moves downward along pin rack 120 , support arm 105 (which may be connected between rake 104 and drive assembly 106 ) may move outwardly due to its connection to drive assembly 106 , causing rack 104 to move outwardly as well. As drive assembly 106 rounds the bottom of pin rack 120 , support arm 105 forces rack 104 against bar screen 102 , trapping the debris therebetween.
[0018] As drive assembly 106 then moves upward, rake 104 drags the debris up along bar screen 102 until it reaches discharge apron 112 . Wiper 114 may then be used to wipe the debris away from rake 104 , forcing the debris down into disposal cart 110 . Once disposal cart 110 is filled, it may be removed and emptied. Of course, those of ordinary skill in the art will appreciate that any means of disposing of the debris may be used instead of cart 110 , such as a conveyor, for example.
[0019] The speed of operation of prime mover 108 may be controlled by controller unit 109 . In the case of a hydraulic motor, for example, controller unit 109 controls the amount (e.g., volume) and pressure of the hydraulic fluid circulating in the system, such as by using a flow control unit. In the case of an electric motor, controller unit 109 controls the speed of the motor, such as by varying the frequency using a variable frequency controller. Of course, those of ordinary skill in the art will appreciate that the invention is not limited thereto and that prime mover 108 and controller 109 may comprise any mechanism for moving a drive assembly 106 , such as pneumatic systems, electromagnetic systems, etc. Moreover, prime mover 108 and controller 109 may comprise one device or several devices for accomplishing the movement of drive assembly 106 .
[0020] A reverse motion proximity switch 118 may also be included for preventing drive assembly 106 from reversing motion over wiper assembly 114 to avoid any damage to wiper assembly 114 . In operation, it may be necessary to reverse the motion of drive assembly 106 , such as for cleaning or manually removing debris from the system. While moving in reverse, as the cogwheel of drive assembly 106 comes into proximity to wiper 114 , proximity switch 118 disengages or stops prime mover 108 , causing drive assembly 106 to stop before it passes over wiper 114 . Similarly, an end of travel proximity switch 122 may be included to stop the motion of drive assembly 106 . As drive assembly 106 contacts end of travel proximity switch 122 it disconnects or stops prime mover 108 , stopping drive assembly 106 . The interaction of proximity switches with electric motors and hydraulic motors is well-known to those of ordinary skill in the art and will not be further elaborated upon here.
[0021] FIG. 2 illustrates a schematic for one embodiment of a variable speed control system in accordance with the invention. As shown in FIG. 2 , motor 204 is connected to fluid pump 210 via coupling assembly 208 . In this embodiment, the speed of motor 204 may remain constant (as the volume and pressure of fluid may be controlled by flow control 216 ). Coupling assembly 208 is also not particularly limited and may comprise, for example, a pump half coupling, motor half coupling, coupling spider and pump/motor adapter, the interconnection of which is well-known of those of ordinary skill in the art. Fluid pump 210 is also not limited, and may comprise, for example, a pressure compensating piston pump.
[0022] Fluid pump 210 may be connected to a pressure compensated flow control 216 through check valve 214 . Shutoff valve and gauge 212 may also be incorporated for measuring the fluid flow from pump 210 . Pressure compensated flow control 216 is not particularly limited and may comprise, for example, adjustable pressure compensated flow control, in which the flow of fluid through the valve may be continuously and/or incrementally varied across the flow range by opening or closing an internal piston within the flow control valve. The variation in flow may be done manually (such as by adjusting a knob) or automatically using a logic board or similar type of controller. The operation of fluid flow control systems is well known to those of ordinary skill in the art and will not be further elaborated upon here.
[0023] Pressure compensated flow control 216 may control the passage of fluid through flow meter 218 to subplate 220 , which contains relief valve 222 . Directional valve 224 may also be included for controlling the direction of hydraulic fluid flow to hydraulic motor 250 . In addition, ball valves 226 may be included to provide flow to hydraulic motor 250 , which may be in communication with drive assembly 106 and/or hoist 120 , and may be driven by the hydraulic fluid circulated through this system in order to control the operation of rake 104 .
[0024] The hydraulic fluid may then flow through check valve 228 and gauge 230 to pressure switch 232 . After passing through needle valve 234 , the fluid may pass through water/oil heat exchanger 236 , where its temperature may be controlled by modulating water valve 240 and solenoid valve 242 . The practice of using heat exchangers in this manner is well known to those of ordinary skill in the art and will not be further elaborated upon here.
[0025] Fluid passing through filter 238 may than be stored in reservoir 202 for reuse by fluid pump 210 . Strainer 250 may also be included for removing particles from this stored fluid to prevent the particles from being carried through fluid pump 210 .
[0026] A temperature/level switch 244 and bulb well 246 may be used for monitoring the level of hydraulic fluid in the system. Ball valve 248 may also be included for draining excess fluid from the system. Fluid may be replaced using an access port at the top of reservoir 202 .
[0027] An alternative embodiment is shown in FIG. 3 . In this embodiment, a variable speed electric motor system may be used. The speed of motor 304 , which maybe located on carriage 106 or located separately therefrom, may be continuously and/or incrementally varied by controller 304 . Motor 304 and controller 306 are not particularly limited, however, but may comprise, for example, a variable frequency drive and multi-phase motor, in which the speed of the motor may be controlled by varying the frequency of the current supplied to the motor. As the speed of motor 304 is varied, the speed of cogwheel 107 of carriage 106 is varied on pin rack 105 , varying the speed of operation of rake 104 .
[0028] Although this invention has been described with reference particular embodiments, it will be appreciated that many variations may be resorted to without departing from the spirit and scope of this invention. For example, any hoist system may be used for moving the rake up along the debris trap, such as, ropes and pulleys, geared systems, a pin rack, etc. Any system capable of moving a drive assembly along this hoist may be used as well, such as electrical, mechanical, hydraulic, pneumatic, electromagnetic, etc.
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The invention is directed to a system for removing waste material from a fluid flowing in a channel. This system may incorporate the use of a trap for collecting the waste material while allowing the fluid to pass; a rake for removing the waste material away from the trap; a drive assembly for moving the rake to remove the waste material; a prime mover for operate the drive assembly; and a variable speed controller configured for operating the prime mover over a variable range of speeds.
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CROSS-REFERENCE TO PROVISIONAL APPLICATION
[0001] This Application claims priority from provisional application No. 60/346,590 entitled “Mechanical Vibration And Group Delay Effects on Recorded/Reproduced Audio Frequency Program Material,” to Ronald L. Meyer, filed on Jan. 7, 2002, which is commonly assigned with the present invention and incorporated herein by reference as if reproduced herein in its entirety.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention is directed, in general, to a microphone holder and, more specifically, to a microphone support system that incorporates vibration shielding and damping to substantially isolate a microphone from extraneous vibrations.
BACKGROUND OF THE INVENTION
[0003] In modern music performance/recording, mechanical vibration effects on recorded/reproduced audio frequency program material are responsible for perceived (and measured) degradation of the natural transient response of all audio signals captured, stored, replayed, or reproduced by equipment of the prior art. It is a problem that exists at the system level, in all components of the system in one form or another.
[0004] The audio industry, since the inception of digital audio in the early 1980s, has faced criticism that digital recordings did not sound as good as their analog counterparts. Indeed, some fine quality recordings were produced by the technology of the late 1950's with analog recording and playback means. This was partially due to the prevalent design techniques used for microphones and microphone stands, along with the materials used in the wiring, and the design of enclosures and chassis. It was also partially due to a more direct signal recording and playback equipment path. That is, there were fewer pieces of equipment to contribute bad effects to the program material, and extra “processing” was not thought of as necessary. Additionally, since the effects of vibration, in some respects, are more detrimental to digital recording and reproduction than to analog processing, the analog recording/playback systems sounded better. In fact, they did indeed capture a better transient response in program material than did the newer digital recordings for reasons disclosed herein.
[0005] Microphones are the most susceptible link in the reproduction chain due to their proximity to the original sound source and their natural susceptibility to vibrations. They are self-evidently and inherently, the most sensitive component due to their function, which is to convert airborne vibrations sensed by the element(s) into low level electrical signals for further amplification, storage, analysis, or later reproduction. However, microphone designers have not successfully understood the issue of microphone enclosure vibrations that are also received from the environment, and how they translate into extra modulations which add to the sound already received and are converted by the main microphone sensing element(s). These enclosure-borne vibrations seriously degrade the signal received by the microphone sensing element(s). More specifically, it has been determined that the resonances of various materials comprising the microphone mounting mechanism(s) and stand assembly can cause smeared signal transients.
[0006] Common sources of vibration (unwanted inputs to the system) include the program material of interest, “monitoring” equipment used to listen to the desired program material during the recording/reproduction process, internal vibrations generated by power transformers or the mechanisms used to manipulate media (CD or tape transports) used to record or process the desired program material. Even air pressure changes caused by low frequency air handler equipment for HVAC systems (Heating, Ventilation, and Air-Conditioning) can cause vibrations to be introduced into the recorded/amplified program.
[0007] The degradation comes in multiple forms, depending on: (a) the type of equipment (analog or digital based signal processing), (b) location in the recording/reproduction chain (microphone or front end processing vs compact disc player playback and power amplifier combination back end processing), and (c) the relative magnitude of the vibration in relation to the signal processing being performed at that stage in the chain. Common effects of the various vibration sources include, but are not necessarily limited to: (a) data clock perturbations in digital systems as a byproduct of the reference crystal vibration (jitter, drift, modulation based on program material), (b) microphonic transfer of vibration to power supply lines which then subsequently modulate the desired program material as a product of amplification, and (c) microphonic transfer of vibration to the microphone electronics through the microphone stand/holder assembly and microphone wiring which then subsequently modulates the desired program material as a by-product of sensing and amplification.
[0008] Referring initially to FIG. 1, illustrated is a conventional microphone stand 100 holding a conventional microphone 110 . The conventional microphone stand 100 comprises a base 120 , a first vertical support pole 121 , a second vertical support pole 122 , an adjustable support pole 123 , a first support pole clutch assembly 124 , a second support pole clutch assembly 125 , a pole-to-microphone adapter 130 , a microphone holder 140 , and cable clamps 150 . The microphone stand 100 stands upon a floor 101 and supports the microphone 110 . The microphone 110 has a microphone body 111 coupled to a microphone cable 160 . The microphone cable 160 is coupled to the first vertical support pole 121 , the second vertical support pole 122 , and the adjustable support pole 123 with the cable clamps 150 . In the embodiment shown, the base 120 , the first vertical support pole 121 , second vertical support pole 122 , adjustable support pole 123 , first support pole clutch assembly 124 , second support pole clutch assembly 125 , pole-to-microphone adapter 130 , microphone holder 140 , and cable clamps 150 typically comprise resonant materials such as metal, hard plastic, etc. In one embodiment, the base 120 may have rubber feet 126 to decouple vibration arising from the floor 101 .
[0009] The major effect of the various vibration sources is the microphonic transfer of vibration to the microphone electronics through the microphone stand/holder assembly and microphone wiring. The vibrations subsequently modulate the desired program material as a by-product of sensing and amplification. In most cases little special care has been taken to isolate the microphone sensing element(s) (not shown) from the microphone body 111 . In an embodiment considered to be among the best of the prior art, the microphone holder 140 comprises some form of elastic suspension bands 141 coupled between a circumferential ring 142 and the microphone 110 . Various forms of this general method of isolation are disclosed in U.S. Pat. No. 6,459,802 to Young, U.S. Pat. No. 4,546,950 to Cech, U.S. Pat. No. 4,396,807 to Brewer, U.S. Pat. No. 4,194,096 to Ramsey, ostensibly to isolate the microphone 110 from floor-borne, low frequency vibrations. The above listed patents are hereby incorporated by reference. While it is desirable to isolate the microphone/stand combination from floor-borne vibrations, the methods of the prior art subject the microphone elements to significantly larger degradations from airborne vibrations through the microphone enclosure (the microphone body 111 or case) which is generally not protected in any way from airborne vibrations. Extraneous vibrations can be additionally magnified when the microphone (sensor) is suspended via these weblike mechanisms, as in the listed prior art, in an effort to isolate it from the low frequency vibrations transmitted from the floor. This is accomplished at the expense of exposure to the significantly higher levels and wider frequency spectrum of vibration levels available directly through the air. These vibrations must also be addressed in the quest to control the recording/reproduction process in an effort to preserve the transient response of the desired signal to be recorded or processed. With the prior art, the conventional microphone 110 receives, and inadvertently converts to an electrical signal, those vibrations it receives through the microphone body 111 and the microphone cable 160 , along with the airborne vibrations sensed by the microphone element from the desired signal. Vibrations in the microphone stand/holder assembly also can cause very small movements of the entire microphone 110 , and therefore the element(s) of the microphone while it is receiving the desired signal. Vibrations of the microphone stand 100 also cause a lever arm effect on the suspended microphone 110 which magnifies the effect of small vibrations in the microphone stand 100 .
[0010] In most cases little special care has been taken to isolate the microphone sensing element(s) from the microphone body. Generally, the microphone itself is, in the presumed best form of the prior art, suspended in air via elastic webs, ostensibly to isolate it from floor-borne low frequency vibrations. While it is desirable to isolate the microphone/stand combination from floor-borne vibrations, the method of the prior art subjects the microphone assembly to significantly larger degradations from airborne vibrations through its enclosure (the microphone body or case) which is not protected in any way from extraneous airborne vibrations. Ideally, the best mounting mechanism would reveal the main (desired) sensing element(s) to the sounds to be converted into electrical signals, while keeping the body of the microphone, and therefore the remaining electronics inside it, isolated from extraneous airborne vibrations. With the prior art, the microphone receives and inadvertently converts vibrations it receives through its case and the microphone wire, along with the vibrations sensed by the main (desired) element from the desired signal. Consequently, any vibrations, including extraneous solid-body vibrations, received through the microphone body ill or its holding mechanism 140 , stand 100 , and cabling 160 get combined with the desirable sounds from an intended source impinging on the main microphone element (s); thereby the net combination of these signals becomes the overall signal produced by the microphone 110 , microphone holding system 100 , and cabling 160 .
[0011] Accordingly, what is needed in the art is a microphone support system that does not suffer from the transmission of extraneous vibrations to the sensing element(s) of the microphone.
SUMMARY OF THE INVENTION
[0012] To address the above-discussed deficiencies of the prior art, the present invention provides a microphone support system that substantially isolates a microphone from extraneous vibrations comprising a base assembly, a microphone support rod, a microphone sheath, a microphone cable, and a microphone cable sheath. In a preferred embodiment, the base assembly is configured to dampen at least some of the extraneous vibrations communicated to the support system. The microphone support rod is coupleable to the base assembly and is configured to support a microphone. The microphone sheath substantially surrounds the microphone and is coupled to the microphone support rod wherein the microphone sheath is configured to substantially isolate the microphone from at least some of the extraneous vibrations. Furthermore, in the preferred embodiment, the microphone cable is coupleable to the microphone, and the microphone cable sheath substantially surrounds the microphone cable and is configured to substantially isolate the microphone cable from at least some of the extraneous vibrations.
[0013] In another embodiment, the present invention provides a method of manufacturing a microphone support system that substantially isolates a microphone from extraneous vibrations. The method includes: (1) providing a base assembly configured to dampen at least some of the extraneous vibrations communicated to the support system, (2) coupling a microphone support rod to the base assembly and configuring the microphone support rod to support a microphone, (3) coupling a microphone sheath to the microphone support rod and substantially surrounding the microphone, the microphone sheath configured to substantially isolate the microphone from at least some of the extraneous vibrations, (4) coupling a microphone cable to the microphone, and (5) coupling a microphone cable sheath to and substantially surrounding the microphone cable, the microphone cable sheath configured to substantially isolate the microphone cable from at least some of the extraneous vibrations.
[0014] The foregoing has outlined preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
[0016] [0016]FIG. 1 illustrates a conventional microphone stand holding a conventional microphone;
[0017] [0017]FIG. 2 illustrates one embodiment of a microphone support system constructed according to the principles of the present invention;
[0018] [0018]FIG. 3A illustrates one embodiment of a microphone holder constructed according to the principles of the present invention;
[0019] [0019]FIG. 3B illustrates an alternative embodiment of a microphone holder constructed according to the principles of the present invention;
[0020] [0020]FIG. 4 illustrates an alternative embodiment of a microphone support system employing non-concentric vertical poles constructed according to the principles of the present invention;
[0021] [0021]FIG. 5 illustrates an alternative embodiment of a microphone support system of FIG. 2 employing a tripod style of a base assembly constructed according to the principles of the present invention;
[0022] [0022]FIG. 6 illustrates an alternative embodiment of a microphone support system employing a ceiling-suspension system that is similar in many respects to the microphone support system of FIG. 2 and constructed according to the principles of the present invention; and
[0023] [0023]FIG. 7 illustrates comparative graphs of system response to a sound as recorded by a conventional microphone on a conventional stand and the same sound as recorded by a conventional microphone on a stand constructed according to the principles of the present invention.
DETAILED DESCRIPTION
[0024] Referring now to FIG. 2, illustrated is one embodiment of a microphone support system, generally designated 200 , constructed according to the principles of the present invention. In the illustrated embodiment, the microphone support system 200 comprises a first vertical support pole 221 , a second vertical support pole 222 , an adjustable support pole 223 , a first support pole vibration-conducting coupling 224 , a second support pole vibration-conducting coupling 225 , a pole-to-microphone adapter 230 , a microphone holder 240 , a microphone sheath 243 , cable clamps 250 , a base assembly 270 , and a counterweight 280 . The microphone support system 200 supports a conventional microphone 210 that has a microphone body 211 . The microphone body 211 is electrically and mechanically coupled to a microphone cable 260 . In a preferred embodiment, the microphone cable 260 is substantially surrounded about its entire length with a vibration-absorbing coating 261 that substantially isolates the microphone 210 from at least some of any vibration that might impinge on the microphone cable 260 . In one embodiment, only those areas of the microphone cable 260 very close to the microphone body 211 , and to the recording/reproduction electronics (not shown) are not covered with the vibration-absorbing coating/sheath 261 . In a preferred embodiment, the vibration-absorbing coating/sheath 261 is polystyrene foam. The microphone cable 260 is mechanically coupled to the first vertical support pole 221 , the second vertical support pole 222 , and the adjustable support pole 223 with the cable clamps 250 . In the illustrated embodiment, the microphone support system 200 is designed to be placed on a support element 201 that may be subjected to extraneous vibrations. In the embodiment shown, the support element 201 is a conventional floor, presumably of a musical performance/recording studio, although the microphone support system 200 may be used at other locations, e.g. a stage, meeting room, etc. In another embodiment, the support element may be a desk (not shown) or any surface suitably strong enough to support the microphone support system 200 . In such a desk-mounted system, as one who is skilled in the art will readily understand, the size and number of the support poles may be significantly reduced while the general principles of the present invention are applied. The extraneous vibrations may be caused by any of the previously listed sources including, but not limited to: a live music source, e.g., musical instruments, and the heating ventilation and air conditioning system (HVAC), etc.
[0025] Details of two embodiments of the microphone holder will be addressed below with reference to FIGS. 3A and 3B. For the sake of the present discussion, it is sufficient to note that the conventional microphone 210 is substantially surrounded by vibration-absorbing or vibration-resistant material (microphone sheath 243 ) in accordance with the principles of the present invention.
[0026] In one embodiment, the base assembly 270 comprises vibration-isolating feet 271 , a vibration-resistant sub-base 272 , vibration-absorbing receptacles 273 , a non-resonant base 274 , and a base assembly cover 279 . In a preferred embodiment, the non-resonant base 274 comprises a circular base made of carbon fiber material such as is produced by Black Diamond Racing, Inc. (BDR), a division of D. J. Casser Enterprises, Inc., Milwaukee, Wis. In one embodiment, the diameter of the non-resonant base 274 may be between about 16″ and 18″. In a preferred embodiment, the non-resonant base 274 may have a threaded hole 275 for coupling to the first vertical support pole 221 . In another embodiment, an upper surface 276 of the non-resonant base 274 may have a threaded flange (not shown) coupled to it for coupling to the first vertical support pole 221 . One who is skilled in the art is familiar with the use of threaded flanges for coupling threaded poles to flat surfaces. Performance of the recording/reproduction system was noticeably better with the threaded hole 275 embodiment.
[0027] In one embodiment, the vibration-absorbing receptacles 273 may comprise carbon fiber “cones” 273 a , “pucks” 273 b , and “pits” 273 c . The cones 273 a , pucks 273 b and pits 273 c may be ones available from BDR. The cones 273 a comprise solid carbon fiber formed as a cone with an imbedded threaded rod 273 d . In a preferred embodiment, the non-resonant base 274 may have a plurality of threaded holes 274 a in a lower surface 277 thereof to which the cones 273 a and pucks 273 b may be coupled in a point-down configuration. The pucks 273 b also comprise carbon fiber similar in appearance to a hockey puck with a central hole 273 e . The pits 273 c are coupled to an upper surface 278 of the sub-base 272 and have a depression 273 f on one surface that receives the point of a cone 273 a . In the illustrated embodiment, the pits 273 c may include an imbedded threaded rod 273 g used to coupled the pits 273 c to the upper surface 278 of the sub-base 272 . In a preferred embodiment, at least three pairs of pucks 273 b , cones 273 a , and pits 273 c are employed.
[0028] In a preferred embodiment, the vibration-resistant sub-base 272 comprises a circular oak plywood disk of a similar size to the non-resonant base 274 . In one embodiment, the sub-base 272 is 1.25 inch thick, circular oak plywood that is a substantially non-resonant material. In one embodiment, the sub-base 272 may additionally be coated with an additional, non-resonant material, such as a fiberglass-reinforced epoxy resin, to further reduce susceptibility to vibration. A suitable fiberglass-reinforced polyester/epoxy resin is Evercoat®, a product of the Fibre Glass-Evercoat Company of Cincinnati, Ohio. In one embodiment, an upper surface 278 of the sub-base 272 may have threaded holes (not shown) configured to accept mounting bolts for BDR “Thick Pits.” The Thick Pits have deep dimples 273 f on their exposed surface to receive points of the cones 273 a . The vibration-resistant sub-base 272 absorbs, through the vibration-absorbing receptacles 273 , at least some of the vibration that may impinge upon the entire microphone support system 200 .
[0029] In a preferred embodiment, the sub-base 272 has vibration-isolating feet 271 coupled to an undersurface 280 of the sub-base 272 . The vibration-isolating feet 271 serve to substantially isolate the vibration-resistant sub-base 272 from at least some of the floor-borne vibrations. In a preferred embodiment, the vibration-isolating feet 271 may comprise rubber bushings. In another embodiment, the rubber bushings may be a type 6 (ribbed bushing) or type 7 (ribbed ring) commonly available from the McMaster-Carr Company of Atlanta, Ga.
[0030] The base assembly 270 may further comprise a base assembly cover 279 substantially surrounding the sub-base 272 , the vibration-isolating feet 271 and the non-resonant base 274 . The base assembly cover 279 couples to the base assembly 270 by surrounding the first vertical support pole 221 and substantially shields the base assembly 270 from at least some of any extraneous vibrations, including airborne vibrations. The vibration-isolating feet 271 substantially isolate the sub-base 272 from floor-borne vibrations.
[0031] The base assembly 270 is coupled to the first vertical support pole 221 as detailed above with or without a flange. In turn, the first vertical support pole 221 is coupled to the second vertical support pole 222 with the first support pole vibration-conducting coupling 224 . The second vertical support pole 222 is coupled to the adjustable support pole 223 with the second support pole vibration-conducting coupling 225 . In a preferred embodiment, the first and second support pole vibration-conducting couplings 224 , 225 are constructed of substantially non-resonant material such as a brass collet and a brass jamb nut. However, these first and second support pole vibration-conducting couplings 224 , 225 are vibration conducting, and will serve to conduct any vibrations impinging upon the microphone body 211 down into the base assembly 270 .
[0032] Additionally, the first vertical support pole 221 , second vertical support pole 222 and the adjustable support pole 223 may be surrounded or coated with a vibration-damping coating 221 a , 222 a , 223 a . The vibration-damping coating may be a flexible rubber. Suitable flexible rubber coatings are also available from McMaster-Carr. In another embodiment, the vibration-damping coating may be polystyrene foam. In yet another embodiment, the vibration-damping coating may be polyethylene foam. In still yet another embodiment, the vibration-damping coating may be elastomeric foam. In a similar manner, the first support pole vibration-conducting coupling 224 and the second support pole vibration-conducting coupling 225 may be constructed of brass, which is substantially non-resonant. In this embodiment, the second vertical support pole 222 and the adjustable support pole 223 may be advantageously hollow and therefore filled with a vibration-damping filler 222 b to effectively dampen the normal resonant modes of the support poles 222 , 223 while allowing high frequency vibrations to be transmitted to the absorbing base assembly 270 . In one embodiment, the vibration-damping filler 222 b comprises lead and sand. In a preferred embodiment, the vibration-damping filler 222 b is a 50/50 mixture by volume of #7 or #8 lead shot and play sand.
[0033] Referring now to FIG. 3A with continuing reference to FIG. 2, illustrated is one embodiment of a microphone holder, generally designated 340 , constructed according to the principles of the present invention. In the illustrated embodiment, a conventional microphone 310 has a microphone body 311 and a hard mount 312 for coupling to a conventional microphone stand 323 . The hard mount 312 also provides for the vibration coupling of the microphone body 311 to the microphone stand 200 of FIG. 2. In this embodiment, the microphone holder 340 comprises a microphone sheath 343 of vibration-absorbing material substantially isolating the microphone 310 from at least some of any extraneous vibration. In one embodiment, the vibration-absorbing material is foam rubber. In another embodiment, the vibration-absorbing material is a polymer resin. In a perferred embodiment, the vibration-absorbing material is Rubatex insulation tape. Rubatex insulation tape is a closed cell, polymer foam insulation tape manufactured by RBX Industries, Inc., of Roanoke, Va. The insulation tape may be wrapped and shaped to ensure minimal impact on the reception pattern of the microphone 310 as well as thorough coverage of the exposed microphone body 311 . The use of vibration-absorbing material allows the sheath 343 to absorb extraneous vibrations, such as airborne vibrations, prior to the vibration's impact on the microphone body 311 . The result is that the microphone 310 is shielded from extraneous vibration, and whatever vibration the microphone body 311 does receive is channeled downward through the stand 200 into the base assembly 270 where absorbing material dissipates the vibration.
[0034] Referring now to FIG. 3B, illustrated is an alternative embodiment of a microphone holder 341 constructed according to the principles of the present invention. In the illustrated embodiment, the conventional microphone 310 has a microphone body 311 but does not have a hard mount for coupling to a conventional microphone stand, thereby requiring a different approach. A microphone 310 of this type typically uses a holder shaped like a circle, or semi-circle, into which the microphone 310 is slid, or a clamp of some sort to grab the microphone body 311 in order to hold the microphone 310 . In this embodiment, the microphone holder 341 comprises a two-part outer shell 342 , 343 , and an inner packing 344 shown as two parts 344 a , 344 b . In one embodiment, the two-part outer shell 342 , 343 comprises a section of PVC pipe shorter than the length of the microphone 310 and cut lengthwise to create two halves 342 , 343 . The two halves 342 , 343 have rounded/sculpted ends to minimize the shielding effect on the desired reception pattern of the basic microphone 310 . In a preferred embodiment, the inner packing 344 comprises a lining of the two halves 342 , 343 with Evercoat. The Evercoat lining comprises a densely packed fiberglass material which allows a good vibration-resistive coupling to the microphone body 311 while enabling a channeling of vibration received by the PVC halves 342 , 343 down into the microphone stand. This effectively isolates the microphone 310 from both airborne and floor-borne vibrations. It should be understood that the alternative microphone holder embodiments of FIGS. 3A and 3B may be employed with any of the microphone stand embodiments of FIG. 2, 4, 5 or 6 .
[0035] Referring now to FIG. 4, illustrated is an alternative embodiment of a microphone support system, generally designated 400 , employing non-concentric vertical poles constructed according to the principles of the present invention. In the illustrated embodiment, the microphone support system 400 comprises a first vertical support pole 421 , a second vertical support pole 422 , an adjustable support pole 423 , a first support pole vibration-conducting coupling 424 , a second support pole vibration-conducting coupling 425 , a pole-to-microphone adapter 430 , a microphone holder 440 , cable clamps 450 , and a base assembly 470 . The microphone support system 400 supports a conventional microphone 410 that has a microphone body 411 that is coupled to a microphone cable 460 . The microphone cable 460 is coupled to the first vertical support pole 421 , the second vertical support pole 422 , and the adjustable support pole 423 with the cable clamps 450 . In the illustrated embodiment, the microphone support system 400 is designed to be supported on a support element 401 that may be subjected to a mechanical vibration. Of course, one who is skilled in the art will recognize that the microphone support system may also be subjected to other extraneous vibrations, such as airborne vibrations, as detailed above.
[0036] The illustrated embodiment of FIG. 4 demonstrates an alternative embodiment of the present invention constructed with non-concentric vertical support poles 421 , 422 . Such a configuration takes advantage of further damping material within the support poles 421 , 422 . In this embodiment, the first and second vertical support poles 421 , 422 are advantageously hollow and are filled with a vibration-damping filler 422 b to effectively dampen the normal resonant modes of the support poles 421 , 422 while allowing high frequency vibrations to be transmitted to the absorbing base assembly 470 . In a preferred embodiment, the base assembly 470 is analogous in materials and construction to the base assembly 270 of FIG. 2. In one embodiment, the first and second vertical support poles 421 , 422 comprise steel. In one embodiment, the vibration-damping filler 422 b is a mixture of lead shot and sand. In a preferred embodiment, the vibration-damping filler 422 b is a 50/50 mixture by volume of #7 or #8 lead shot and play sand.
[0037] Referring now to FIG. 5, illustrated is an alternative embodiment of a microphone support system of FIG. 2, generally designated 500 , employing a tripod style of a base assembly constructed according to the principles of the present invention. In the illustrated embodiment, the microphone support system 500 comprises a first vertical support pole 521 , a second vertical support pole 522 , an adjustable support pole 523 , a first support pole vibration-conducting coupling 524 , a second support pole vibration-conducting coupling 525 , a base-to-pole vibration-conducting coupling 526 , a pole-to-microphone adapter 530 , a microphone holder 540 , cable clamps 550 , and a base assembly 570 . All components above the base-to-pole vibration-conducting coupling 526 are analogous to and therefore may be identical to the associated components of the microphone support system 200 of FIG. 2.
[0038] In the illustrated embodiment of FIG. 5, the base assembly 570 employs a tripod style of base assembly. In one embodiment, the base assembly 570 comprises vibration-isolating feet 571 , a vibration-resistant sub-base 572 , vibration-absorbing receptacles 573 , and a plurality of non-resonant legs 574 . In one embodiment the microphone support system 500 may also comprise a base cover (not shown). In a preferred embodiment, the plurality of non-resonant legs 574 comprises hollow steel poles with a vibration-damping coating 575 or a vibration-damping filling as in the support poles 421 , 422 of FIG. 4. In one embodiment, the base-to-pole vibration-conducting coupling 526 comprises non-resonant materials such as a brass/PVC combination and may additionally comprise a vibration-damping coating 575 . The vibration-isolating feet 571 , vibration-resistant sub-base 572 , and vibration-absorbing receptacles 573 are analogous and may be identical to the associated components of the microphone support system 200 of FIG. 2. In one embodiment, the vibration-absorbing receptacles 573 may be pits similar to the pits 273 c of FIG. 2. In another embodiment, the sub-base 572 may additionally be coated with a non-resonant material, such as Evercoat, the fiberglass-reinforced epoxy resin detailed above, to further reduce susceptibility to vibration.
[0039] Referring now to FIG. 6, illustrated is an alternative embodiment of a microphone support system, generally designated 600 , employing a ceiling-suspension system that is similar in many respects to the microphone support system 200 of FIG. 2 and constructed according to the principles of the present invention. The microphone support system 600 holds a conventional microphone 610 . In the illustrated embodiment, the microphone support system 600 comprises a vertical support pole 621 , a horizontal support pole 622 , a microphone holder 640 , cable clamps 650 , a base assembly 670 , and a counterweight 680 . The microphone support system 600 is suspendable from a ceiling beam(s) 601 .
[0040] In a preferred embodiment, the base assembly 670 comprises vibration-isolating feet 671 , a vibration-resistant sub-base 672 , and vibration-absorbing receptacles 673 . In the illustrated embodiment, the base assembly 760 also includes support cones 674 that are coupled to the horizontal support pole 622 and are configured to rest upon the vibration-absorbing receptacles 673 . All components below and including the vertical support pole 621 are analogous to and may be identical to similar components of the microphone support system 200 of FIG. 2.
[0041] Referring now to FIG. 7, illustrated are comparative graphs of system response to a sound as recorded by a conventional microphone on a conventional stand and the same sound simultaneously recorded by a substantially-identical, (both microphones have matched performance graphs) conventional microphone on a stand constructed according to the principles of the present invention. The upper chart 710 (left channel) illustrates the response of a conventional microphone shielded and mounted on a microphone support system of the present invention as described above. The lower chart 720 (right channel) illustrates the response of a conventional microphone mounted on a conventional microphone stand to the same sound. As can be seen, the amplitude (percent of full scale) response of the left channel (present invention) is approximately 10 percent higher throughout than the response of the right channel (conventional system). The difference between the two systems (what could be characterized as the left channel signal minus the right channel signal) illustrates the corruption in the desired signal caused by vibration-induced effects on the microphone sensing element(s) and the amplification electronics.
[0042] Thus, an improved microphone support system with vibration damping material applied to, or used in construction of, each component of the microphone support system has been described. The effect is to substantially inhibit the effects of unwanted extraneous vibrations that would otherwise impinge upon the microphone and its body, thereby causing undesirable alteration of the signal to be recorded or reproduced by the system electronics.
[0043] While the preferred embodiment as described includes a number of enhancements associated with each of the above listed elements of the microphone support system, one who is skilled in the art will recognize that at least some improvement in a recorded/reproduced audio signal may be realized by some smaller set of individual enhancements to the listed elements.
[0044] Although the present invention has been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the invention in its broadest form.
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The present invention provides a microphone support system and a method of manufacturing that substantially isolates a microphone from extraneous vibrations. In one embodiment, the microphone support system comprises a base assembly, a microphone support rod, a microphone sheath, a microphone cable, and a microphone cable sheath. The base assembly is configured to dampen at least some of the extraneous vibrations communicated to the support system. The microphone support rod is coupleable to the base assembly and is configured to support a microphone. The microphone sheath is coupled to the microphone support rode, substantially surrounds the microphone, and is configured to substantially isolate the microphone from at least some of the extraneous vibrations. Furthermore, the microphone cable is coupleable to the microphone, and the microphone cable sheath substantially surrounds the microphone cable and is configured to substantially isolate the microphone cable from at least some of the extraneous vibrations.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application relates to another application filed of even date herewith, with common assignee, and entitled: “Computer Network Events-Notification System, Apparatus and Method under User Control”.
FIELD OF THE INVENTION
The present invention generally relates to a computer network events-notification system, apparatus and method, and, more particularly, relates to device management software under user control at a client or head-end station which manages the monitoring and reporting-on of events throughout the network.
BACKGROUND OF THE INVENTION
Computer networks are pervasive in our society and virtually all human activity is now influenced at least to some extent by existence and usage of these networks. Therefore, the more reliable these networks are, the better for all concerned. Accordingly, substantial effort is being invested in improving reliability and long-term operability of these networks. One current approach to improving computer network reliability is to continuously monitor events or operating states of peripheral devices on an individual basis in the network to determine if those states reflect normal or failing peripheral-device operation. Each peripheral device or group thereof has its own individually dedicated server for performing at least that monitoring function. If such monitoring allows for sufficiently early notification of an event such as a failing device or portion thereof, (e.g., in a disk drive peripheral, failure-events such as cooling-fan failure, bad fuse, ac power failure, invalid data sector read, checksum error, inconsistent time stamps, incoherent stripe, etc. can occur), then action can be undertaken in an attempt to avoid or mitigate effects of the particular failure mechanism(s) involved. Accordingly, overall system or network reliability is generally enhanced by such timely event-notification and response thereto. But, setting-up the notification system on an individual basis, and monitoring and reporting events on an individual basis is problematic as discussed further below.
Typically, in the aforementioned prior art, operating states of hardware peripheral devices, such as, for example, disk drives, are monitored and software is utilized as the avenue by which such monitoring is performed. Distributed management software running in client server networks is available now for these purposes. In this prior art, as noted, a server-host computer is normally associated with, or dedicated to, a group of peripherals including disk drives and is tasked with monitoring events (such as failures) associated with those peripherals and reporting such events to its client. However, since each such group of peripherals has its own server for that purpose, each such server operates in this events notification arena independently of all other servers in the network. Thus, there is a one-to-one relationship between any disk array and the server computer monitoring it. This arrangement necessitates the programming and set-up of each such server on an individual basis to monitor a particular peripheral or group of peripherals. In other words, in the prior art, methodology for handling this peripheral device state information, or system event configuration information, involves a manual set-up on a per-host basis (one server at a time). This set-up is accomplished by editing a text-based configuration file which is very time consuming and error-prone. And this arrangement offers further complexity if changes or upgrades are required: for example, if a new computer network service person hires-on with a new pager number, it is a non-trivial challenge to travel to each separate storage system on a network of, for example, a thousand or more disk drive peripherals scattered geographically around the nation (or, even worse, around the globe) in order to properly upgrade the pager number for each peripheral device cluster. Additional challenge is presented in the events-notification arena by pre-existing network state conditions wherein portions of a client's database contain data in conflict with other data contained in portions of one or more of its servers' databases. These complexities, limitations and challenges of the prior art are addressed and overcome while further enhancing reliability of network operation, by the welcome arrival of the present invention.
SUMMARY OF THE INVENTION
In certain embodiments of the present invention which avoid the aforementioned prior-art one-to-one relationship between server and peripheral cluster in the event-notification arena, control over all event notification activity in the network is placed with the network's user at a single point in the network by virtue of novel improvements made to existing distributed management software. In these embodiments, system, apparatus, method or computer program product is provided to enable the client to permit the network user to establish an events-notification system wherein template software objects of event-errors of interest are created at the user interface and deployed to the servers' databases, while at the same time ensuring that any pre-existing server-database template objects and identically-named client template objects contain identical object data. Such template software objects, created and deployed as noted, and ensuring unambiguity as noted, are also compatible with and useable in Storage Area Network (SAN) and Network Attached Storage (NAS) environments.
In further features of these embodiments of the present invention, either a system including its sub-system components, apparatus, method, or computer program product including programmable code, is provided to enable the client to permit the user to retrieve any pre-existing server-database template objects and compare their names with those stored in the client-database, add new templates to the client database comprised of pre-existing object data from any pre-existing template objects with names that do not match client template object names, and resolve any conflict between any pre-existing server-database template objects and any client template objects having identical names but having different data.
In yet another feature of these embodiments of the present invention, the client permits the user to resolve such conflict by either deleting conflicting server-stored template objects, renaming server-stored template objects, updating server-stored template objects, or taking other action to resolve the conflict.
In still another feature of the present invention, purging ambiguity between a client or primary template object and any pre-existing server-location or network-remote template objects involves apparatus, methodology, computer program product or a system for permitting the client to retrieve pre-existing server-location template objects, compare names of each of the pre-existing objects with all names in the client template-object, add pre-existing template object data to the client template object from pre-existing server objects having names that do not match client template object names, compare pre-existing contents of pre-existing server objects with other contents of the client template object for client and server objects having the same name and to purge ambiguity if the compared contents are different.
In an alternative embodiment of the present invention, an events notification system deployed across multiple client-server networks, under the conditions of a client from one network being operatively coupled to a server of a different network, updates templates on the different-network server to conform to otherwise conflicting templates on the client from the one network. And the different-network client updates the templates in its database to conform to the updated templates in the different network server.
It is thus advantageous to use the present invention to improve reliability of computer networks utilizing network-distributed event-notification techniques without encountering the complexities, inconveniences and shortcomings of the prior art approaches to reliability enhancement.
It is therefore a general object of the present invention to provide improved computer networks.
It is another object of the present invention to provide improved client-server computer networks, including those operating within SAN (Storage Area Network) and/or NAS (Network Attached Storage) environments, with enhanced reliability due to utilizing network-distributed event-notification techniques that can purge ambiguity in, and resolve conflicts between, conflicting databases located respectively on the client and on its server(s).
Other objects and advantages will be understood after referring to the detailed description of the preferred embodiments and to the appended drawings wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a network of the type for which the present invention would provide enhanced reliability;
FIG. 2 is a flowchart depicting an algorithm useful with the present invention and associated with use of a template object by a server to process events and notify the user;
FIG. 3 is a flowchart depicting an algorithm useful with the present invention and associated with the user-interface at the client creating a template object;
FIG. 4 is a flowchart depicting an algorithm useful with the present invention and associated with the user-interface at the client applying a created template-object to specific server(s) in the network;
FIG. 5 is a flowchart depicting an algorithm of an aspect of the present invention associated with synchronizing between, or purging ambiguity of, pre-existing template-object contents and template-object names on the one hand and newly-retrieved template-object contents and template-object names on the other hand;
FIG. 6 is a flowchart depicting an algorithm of an aspect of the present invention associated with resolving any conflicts in template-object names and contents uncovered through use of the algorithm depicted in FIG. 5 ;
FIG. 7 is a block diagram of an alternative embodiment of the present invention wherein features of enhanced reliability provided thereby are applied to multiple clients sharing one or more common servers; and,
FIG. 8 is a facsimile of a dialog box of the type that could be employed within the present invention at the user interface.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Prior to discussion of FIG. 1 , it should be understood that certain terms herein are used interchangeably. The terms client, head-end station, head station or work-station all refer to the same section of a computer network having a terminal typically with keyboard and mouse interface (collectively, user interface) and local storage (local database or client database), such section being in charge of, in control of, the head of, or the client demanding service from, the remainder of its network or system. And, the terms server, server location, host, agent, remote agent all refer to other section(s) of the network each including processing, storage and other peripheral functions responding to commands from the client and serving the client in response to those commands. A template is a software object or container, which holds data structures, commands, and other binary information, and which is capable of user manipulation or configuration at the location of the user interface. The template holds specific binary information pertaining to: (1) screen displays for the user interface such as dialog boxes, check boxes, etc.; and/or (2) substantive content on, or information contained within or represented by, such screen displays including at a minimum: (a) different kinds of events; (b) varying severity of the different kinds of events; and, (c) various kinds of responses to each of the various event occurrences. The templates or portions of binary information contributing to such templates are deployable or assignable throughout the network by the user at the user interface which is capable of being situated at one location in the network. The user-interface is that connective boundary between the human-user and the computer system, typically conceived as the client terminal's screen with keyboard/mouse interaction. In a client server network, whether or not included in or with a SAN or NAS environment, the client and its servers including communication therebetween and client-control thereover comprise a system, with such servers and their respective processors and storage being sub-system components therein. Peripheral cluster includes such storage and any other peripheral devices under control of its respective server.
FIG. 1
Referring to FIG. 1 , a block diagram is shown of a client-server network of the type for which the present invention would provide enhanced reliability. Client (or head station) 101 presents a user interface (UI) for a user of the network via its terminal screen and keyboard at a single point of control in the network. Typical computer system dialog, edit, and check boxes, etc. are presented on the screen which the user can configure and with which the user can interact, and about which more will be discussed in connection with FIG. 8 hereinbelow. Additional screen shots (screen display facsimiles) and other relevant information is published in “EMC Navisphere Event Monitor Version 4.X USER GUIDE P/N 069000970-00” having 122 pages, printed by EMC Corporation, Hopkinton, Mass., October, 2000, and incorporated herein by reference in its entirety. Storage device or disk array 105 is operatively coupled to client 101 and contains at least the client's database. Client or user templates 110 are shown associated with client 101 . They are software objects which are stored in storage device 105 and subject to user control and deployment throughout the network by way of operation of client 101 with which the user interfaces, as noted. Templates 110 will be discussed in more detail in connection with other figures hereinbelow.
Servers 102 , 103 , and 104 are shown operatively coupled via network bus 114 from Client 101 in this client-server network. Any or all of these servers can be remotely located at widely-displaced geographical distances from the client or can be located physically near the client. Also, it is to be understood that a vast number of servers (up to 1000 or more) can be connected on any particular network and only three are shown in this Figure for purposes of enhancing clarity of presentation. Server 102 is operatively coupled to disk array or storage device 106 ; server 103 is operatively coupled to disk arrays or storage devices 107 and 108 as well as to network cloud 115 representing Network Attached Storage (NAS) or Storage Area Network (SAN) environments and designated herein SAN/NAS or NAS/SAN for convenience purposes; and, server 104 is operatively coupled to storage device 109 . Server templates 111 are shown associated with server 102 and are stored in storage device 106 ; server templates 112 are shown associated with server 103 and are stored in storage devices 107 and/or 108 as well as within storage devices (not shown) operating within or associated with NAS/SAN cloud 115 ; and, server templates 113 are shown associated with server 104 and are stored in storage device 109 . These server templates are also software objects and they have been deployed or assigned by client 101 to databases in their respective server-based storage devices. Host or client 101 where the configuration UI software is running maintains a database on its storage device 105 of all server templates used throughout the site or network (in this instance templates 111 , 112 , and 113 ). These server templates as well as the client templates are thus also under control of client 101 and will also be discussed in more detail in connection with other figures hereinbelow.
FIG. 2 —Server Activity
Referring to FIG. 2 , a flowchart is presented which depicts an algorithm useful with aspects of the present invention and which is associated with use of a template software object in a client-server network by its server to process events and notify the user of those events. The algorithmic process starts with block 201 which represents the step by which such event is detected. This event could be, for example, a failure in a disk drive, such as a fan failure, fuse failure, etc. The algorithmic process moves next to block 202 where a template stored in the database associated with that server is obtained (e.g. in FIG. 1 , template 111 from the database stored within storage device 106 associated with server 102 ). The algorithmic process moves next to decision block 203 where it is determined if the detected event is covered by that obtained template. On the one hand, if that event is covered by such template, then the algorithmic process moves to block 205 representing steps to be taken to launch responses defined in the template. Such notification option responses could include, for example, the sending of an email to a particular email address or addresses advising of the particular component failure; in lieu of, or in addition to, such email response(s) another response, for example, could be to send a pager alert to page an individual or group of individuals. These notification options thus result in template options. Other responses including “specials” designed by the user such as, for example, robot intervention, substituted components, etc. could be employed. Presumably, such notifications of the occurrence of this event would bring about human reactions whereby such event would be handled or managed in a manner to mitigate any potential network-disaster ramifications. On the other hand, if such event is not covered by the obtained template, the algorithmic process moves to decision block 204 whereby a determination is made regarding the existence of any more templates in this particular server's database. If “yes, there are more templates” then the algorithmic process returns via line 206 to block 202 to obtain a heretofore “unobtained” (for this particular event examination subroutine) template which is then examined in block 203 as before to see if it covers the event and processed as described above. But, if “no, there are not any more templates”, then the process is “done”, as there are no more templates to examine.
Returning this discussion to block 205 , after the responses to this particular event such as email and/or paging are launched, the algorithmic process returns to block 202 via line 207 to determine if such event is also covered by any other templates in that server's database by iteratively cycling through blocks 202 , 203 , and 204 until it is determined that there are no more templates covering such particular event. As an alternative embodiment, after the responses are launched in accordance with block 205 , the algorithmic process at block 205 need not move via line 207 to block 202 , but instead could move via line 208 to “done”, where it is assumed in this alternative embodiment that there are no other templates covering such event in that server's database.
FIG. 3 —Creating a Template
Next, referring to FIG. 3 , a flowchart is presented depicting an algorithm useful with aspects of the present invention and associated with creating a template software object at the client or head-end station by way of the user-interface.
In block or step 301 , events of interest are selected or chosen to be covered by the template. In other words, the user determines which particular events, are to be monitored, whether they be full failure events, or degraded operating condition events, or other events. This determination can vary from template-to-template depending on which particular server-storage subsystem in the network is being targeted for monitoring. Certain subsystems may have a propensity for certain degradation or failure modes as opposed to others. These selections are made at a single point or location in the network by the usual point-and-click technique at the user interface, about which more detail will be provided in connection with FIG. 8 .
The algorithmic process moves next to step or block 302 wherein the next selection is made—selection of responses desired when events selected in block 301 are detected. All responses for all events can be identical, e.g., selection of only email responses for any detected event. Or, each response can be tailored for each event, e.g., email responses for fan failures sent to first service personnel, and pager responses for ac power failures sent to second service personnel, etc. Again, these response selections are programmed into the system via the user interface, at a single point of contact in the network, where all of these response selections can be conveniently planned at time of their creation for subsequent deployment. For example, two different templates can be conveniently and serially created by a user at a single point in the network at the head-end station for covering identical events occurring at two different server subsystems located in very different regions of the country, where each subsystem would be better serviced by signaling a different response tailored to their different regional locations, with the user's advance knowledge that either or both of these different templates can be deployed or assigned to these different server locations at separate times and when desired. Of course, it is conceivable that this convenient template creation activity can be expanded to hundreds or even thousands of templates, each being conveniently created slightly differently from others for optimization purposes for usage at hundreds or even thousands of different server locations respectively.
The algorithmic process next moves to step 303 where format of the message or response to be received by the user is selected. Format is associated with how the message would look or sound, depending on the nature of the response. In an email, for example, look or layout of the message in the email can be textual or can be pictorial if documents are attached, etc. In an audio response, if a telephone message is generated as the response, the verbally-provided explanation can take various forms including, e.g., different background music or sound styles suggestive of different levels of severity of the problem being reported. A different format can not only be selected for each template, but can also be selected for each response within the same category of responses within the same template. For example, for the email category of responses, there can be a different kind of email format selected for each different kind of event within one particular template used with a single server subsystem having one or more disk drive systems operatively coupled thereto. For example, emphasis such as capitalized letters, boldface or italicized text, or frames or borders around certain text can be provided.
Next, in step 304 , the template software object is created from data generated in steps 301 , 302 , and 303 , i.e., the template is constructed at the user interface from selected (or ranges of) events, selected (or ranges of) responses, and selected (or ranges of) message formats. The template is written to the client's diskdrive, where it is stored, e.g., diskdrive 105 associated with client 101 of FIG. 1 . This allows the user to shut-down the client computer, or head-station, without needing to recreate the template. Templates created and stored in the hard-drive will be permanently available for future deployment as the network expands or changes. Thus a database or repertoire of many templates for different requirements can be built-up in advance and stored on the head-station disk drive. Accordingly, tremendous flexibility is available to the user in that these templates can be tailored for particular circumstances, and for varying circumstances: e.g. a template which requests paging responses for weekdays can switch to requesting email responses over the weekends and holidays! Other templates can be created to run virtually any user program as a response to an event, where the user program could fail-over to another machine offering redundancy in the network; alternatively, the user program could attempt to fix the problem associated with the detected event, even sending a robot to the rescue in certain classes of failures, such as removing and replacing a broken disk drive!
FIG. 4 —Applying a Template
After a template(s) is created by the user as discussed relative to FIG. 3 , it has to be properly deployed or applied at specific locations throughout the network as desired by that user. Accordingly, referring next to FIG. 4 , a flowchart is presented depicting an algorithm useful with aspects of the present invention and associated with asserting, or controlling application of, a created template-object to specific server(s) in the network from the user-interface located at the client or host-station. The algorithm starts with step or block 401 where the user at the user interface (using the point/click technique on the appropriate dialog box on the terminal screen, to be discussed further hereinbelow) chooses a particular template from a group of templates that had been created in accordance with FIG. 3 , and stored in the client's database, e.g., in storage device 105 of FIG. 1 . This selection is made based on user's knowledge of what kinds of events, what kinds of severity levels for each of those events, and what kinds of responses have been designed-into this particular template.
Next, in step 402 , the user chooses the particular host (server) or hosts running agent software that are to be monitored by this template, by, e.g., pointing/clicking on a tree display in an event configuration dialog box displayed on the terminal screen at the user-interface. Further detail about this user interface operation will be discussed hereinbelow in connection with FIG. 8 . Next, in step 403 the user chooses certain storage system(s) operatively coupled to the particular host(s)/server(s) upon which the user wants this particular template to be asserted or applied. In other words, there may be multiple storage systems as, for example, disk drives 107 and 108 or others (not shown) associated with SAN/NAS cloud 115 connected to host/server 103 in FIG. 1 , where a template could be applied to only disk drive 107 and not disk drive 108 , or vice-versa, or only to certain others associated with cloud 115 and neither 107 nor 108 .
In step 404 , user forwards the template chosen in step 401 to the server subsystem (remote agent) associated with the storage system(s) selected in step 403 . For example, in FIG. 1 , one of the templates shown in group 110 would be sent to host 103 for application to one of the disk drives 107 or 108 or connected with cloud 115 . Also, in step 404 the server or host associated with the selected storage system(s), e.g. host 103 , and the selected storage system, e.g. disk drive 107 , are commanded to start using the forwarded template immediately. In step 405 the remote agent saves a local copy of the forwarded template on its relevant disk drive and starts using the template immediately, and the algorithm is then “done”.
FIG. 5 —Purging Template Ambiguity
The foregoing algorithms and discussion thereof set forth essentials of operation of an events-notification scheme with which certain embodiments of the present invention, involving template-calibration or template-synchronization or template-ambiguity-purging, are particularly useful. These embodiments ensure against multiple templates with the same name having different contents, which, if not corrected are erroneous conditions which can negatively impact operation of the events-notification scheme. Referring to FIG. 5 , a flowchart depicts an algorithm of an aspect of the present invention associated with purging ambiguity in a situation where pre-existing server template-object content has a certain name and different pre-existing or newly-retrieved client template-object content has the same certain name. The algorithm starts with step 501 where the head-end station (client) retrieves a particular pre-existing template from a particular database maintained on a particular storage device associated with a particular server-host, such as, for example, template 113 from a database maintained on storage device 109 associated with host 104 in FIG. 1 . (Such particular template could have been located on a storage device associated with a host (not shown) within or related to cloud 115 of FIG. 1 .) After retrieval is accomplished, the algorithmic process moves to decision block 502 wherein a comparison is made between the name of this retrieved pre-existing server template and the name of every template in this head-end station database. If the name is not the same the algorithmic process moves to block 507 wherein the retrieved template is added to this head-end database. Block 507 is returned to the start of block 501 where the next template is retrieved. But, if the name of the retrieved pre-existing template was the same as, or identical to, the name of any template in the head-end station then the algorithmic process would have moved to decision block 503 . In block 503 , a decision block, the two identically-named templates' contents are compared and if the contents are not identical the process moves to block 508 . In block 508 the conflict is resolved and the process moves from there back to the beginning at block 501 . The input to and output from block 508 are tabbed “A” and “B” respectively to coordinate with FIG. 6 which is a subroutine comprising block 508 and about which more discussion will take place hereinbelow.
However, if the two identically-named templates' contents are identical then the process moves to decision block 504 wherein the query is posed: are there any other unretrieved templates in this remote agent database (in the database on the disk drive associated with the server/host)? If “yes” then the algorithmic process loops back to “start”, is repeated, and continues to loop back until all other unretrieved templates (step 504 ) in this disk drive are retrieved; if “no” the process moves to block 505 .
At this point in the algorithm of FIG. 5 , all pre-existing templates stored in this particular remote agent database have been compared with all pre-existing (if any) and newly-retrieved templates stored in the client database, and all ambiguities, if any, regarding names and contents of templates for this particular remote agent database have been resolved. However, there may be other remote agents serving this head end station, as, for example, consider the three remote agents 102 , 103 , and 104 of FIG. 1 where only one had been compared and cleared. Accordingly, the algorithmic process moves next to block 505 wherein the query is posed: are there any other remote agents serving this head-end station? If yes, then the entire algorithmic process from “start” up to this point is repeated as depicted; but, if “no”, then the process is “done”.
FIG. 6 —Template Name/Contents Conflict Resolution
Referring to FIG. 6 , a flowchart depicts an algorithm of another aspect or further feature of the present invention associated with resolving any conflicts between template-object names and contents uncovered through use of the algorithm of FIG. 5 . The “A” tab at “start” and the “B” tab at “done” indicates that this flowchart fits within the “A” and “B” tabs of FIG. 5 . Block 601 refers to the step where the user is prompted to resolve, at the user interface, a conflict between name and contents in two templates. Decision block 602 allows the user to delete the conflicting retrieved template; if deleted by the user the procedure is “done”. If not deleted, the procedure moves to decision block 603 which allows the user to rename the conflicting retrieved template; if renamed by the user the procedure is “done”. If not renamed, the procedure then moves to decision block 604 which allows the user to update the remote server's copy of the conflicting retrieved template with the contents of the client's template; if updated the procedure is “done”. If not updated the procedure then moves to decision block 605 which allows or requires a different user to update a local template on a different client about which more will be explained in connection with FIG. 7 hereinbelow. If not updated the procedure then moves to block 606 generically entitled “take other resolution action”. Block 606 refers to “special” resolution action, such as, for example, running user's software to generate a fix or bringing in a robot to perform a robotic activity. If such special action is taken the procedure is “done”. If no special action taken, the procedure moves to “do nothing” block 607 and the procedure is “done”.
Circumstances under which a user might prefer delete to the other actions could be where he/she does not want the template to be present any longer; another template can be added at a later time. Circumstances under which a user might prefer rename to the other actions could be where the user wants the template contents on the remote host to remain as they are, but needs to resolve the naming conflict, where the action of merely renaming the remote host template accomplishes this goal. Circumstances under which a user might prefer update to the other actions could be the most common case, where the user wants to update the template of the same name with the contents of the client's database. And, circumstances under which a user might prefer other resolution action could be where none of the foregoing choices are desirable or where another special choice available to a particular user is an optimum choice under the then circumstances of that particular user.
FIG. 7 —Alternative Embodiment—Multiple Clients
Finally, there could be a network scenario where there are separate networks each having their own segregated clients and servers, but where one or more servers from one or more other networks, for some reason, have been arranged to interact with the above-noted client of this network. Referring to FIG. 7 , this scenario is presented in a block diagram. The above-noted client C 1 701 (equivalent to Client 101 of FIG. 1 ) is shown operatively networked to server-database combinations or server-locations 703 , 704 , and 705 (for purposes of simplification, these three singular blocks should be viewed as combining the functions of server, database, and template as represented separately in FIG. 1 ). Components 701 , 703 , 704 , and 705 comprise network I, as shown, which is separated from network II by imaginary demarcation line 709 . (Many more networks which could have been shown with many servers per network are not shown to enhance clarity of presentation.) Network II comprises different client C 2 702 which is operatively coupled to its server-database combinations 706 , 707 , and 708 (to be viewed similarly to 703 , 704 , and 705 ). The cross-network connection 710 shows that above-noted client 701 is operatively coupled out of its normal network to server 708 . In this instance if there is a conflict between names and contents of templates stored on databases associated with server 708 and client 701 , client 701 updates conflicting templates stored on databases in server 708 conform to its own templates. In such a case, such updated templates in server 708 are also changed relative to expectations of other client C 2 702 . However, an assumption is made that Client C 1 is operating with new data and Client C 2 is operating with old or obsolete data. In other words, the most current event-notification-establishment-user can over-ride template names or contents for templates stored in databases of servers that are common to itself and other clients. Thus if client C 2 702 had established its event-notification parameters earlier than the establishing of event-notification parameters for client C 1 701 , then any client C 1 701 templates imposed on databases associated with server 706 in Network II shall be further imposed on Client C 2 702 as being the “latest” or “most preferred” event response or template. This is summarized in decision block 605 of FIG. 6 as an action to resolve conflict by “update local template”, which means, in terms of the example and scenario used herein, to update the local template in client C 2 702 .
FIG. 8 —Template Property Dialog Box
FIG. 8 is a facsimile of a dialog box, entitled “Template”, of the type that could be utilized within disclosed embodiments of the present invention. (In FIG. 1 , client's templates 110 include dialog boxes such as the one shown in FIG. 8 .) This dialog box and other similar graphical user interface boxes and icons with their responsiveness to “point and click” of the mouse and to inputs from the keyboard are essentials of the aforementioned “user interface”. In other words, the present invention provides device management software which runs on various computer systems and which offers a user the convenience of selecting, at a single point in the network, various devices to monitor, the manner by which monitored events shall be reported, to whom such reports shall be sent, and other related activities. All of this control and management is achieved by the user interacting with various screen presentations generated by such software. For example, in the right hand portion of FIG. 8 “Event Category” is offered by way of checkboxes, and “storage system” is shown checked in the Figure, which was achieved by pointing to and clicking on that particular checkbox with the mouse associated with this client's terminal. Other event category checkboxes shown are “network”, “navisphere application”, “array software”, “storage processor state”, “HBA” (host bus adapter), and “JBOD” (just bunch of disks). Also shown below the Event Category is another section of checkboxes entitled “Event Severity”. There are four check boxes and two are shown as checked: “Error” and Critical” are checked, and “Information” and “Warning” are shown unchecked. In this manner a particular user, being interested in events of only a particular severity, can control number of notifications received about events associated with a particular piece of hardware. In this example, hardware involved is the checked “storage system” shown under the event category and the only notifications received will necessarily meet the standard of “error” and “critical” in accordance with their checked boxes. Thus other errors that rise only to the level of “warning” or “information” will not be forwarded to the user.
As is to be understood, FIG. 8 depicts a “windows” type of screen display, and a portion of a window underlying the “Template” dialog box, entitled “Event Monitor Configurator” is shown at the left-hand side of the Fig. It can be seen that the Configurator shows a “tree” presentation of servers with their associated storage devices as well as a tree presentation of templates with their respective event response directives. The rest of the nomenclature shown in that view and in the view of another window underlying that view is nothing more than typical information that could be so displayed, and it has no further relevance to operation of the present invention. In the usual fashion when dealing with Microsoft Windows styled software, the underlying Event Monitor Configurator can be brought to the top of the window pile and available icons can be selected by point and click techniques to allow the user to select amongst the servers and their respective storage systems and to choose templates and responses as noted.
It is to be understood that this singular screen display facsimile is intended to represent the concept of providing the user with a multiplicity of similar displays of various types having various modes of interaction (such as edit boxes, radio buttons, checkboxes, clickable icons, tabs, control buttons, etc.) that would be made available by running the software of the present invention. Such additional screen displays are not included as they would not further enhance clarity of presentation of the present invention. However, the incorporated-by-reference “EMC Navisphere Event Monitor Version 4.X User Guide” offers additional screen shots (screen display facsimiles) and other information which are useable and useful at the user interface in connection with operation of the present invention. Software of the present invention has been implemented in C++ programming language. Alternatively, other programming languages are suitable for use in implementing the various embodiments of the present invention and they include C, JAVA, assembly language, etc.
Various embodiments of the present invention are to be considered in all respects as illustrative and not restrictive. Other algorithmic schemes may be employed to accomplish the various aspects of the present invention. For example, in FIG. 5 , all templates could be retrieved simultaneously as opposed to the sequential operation shown. In FIG. 6 , fewer or more choices could be provided for the user, or these actions could be selected automatically without involving user choice. In FIG. 7 , more clients could be included and more interconnections between and amongst clients from one network to servers from another network could be made than only those that are shown. And, embodiments of the present invention are readily applicable to the SAN (Storage Area Network) environment, the NAS (Network Attached Storage) environment, as well as the Client-Server environment. Scope and breadth of the invention is indicated, therefore, by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
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There is disclosed an improvement to a system, apparatus, method, and computer program product relating to a novel events-notification activity occurring within computer network environments including SAN, NAS and client server environments. A user at a convenient, single user-interface location in a network is enabled to establish such activity by creating and deploying template software objects which are configurable with respect to both events of interest and genre of notifications of such events. Accordingly, such user, operating at the user-interface at a client or head-end station and employing such templates, can select: (1) which particular network-failure events (from complete failures to measured degradations), such as those occurring in peripherals including disk array storage devices, are to be reported; (2) to whom such events shall be reported, worldwide; and, (3) the mode of communication by which such events shall be reported such as email, telephone, pager, etc. In those instances where certain databases in storage devices of servers employed throughout the network may contain templates which present name/content conflicts with client database templates the events-notification activity is less effective than it otherwise would be. There is disclosed a system, apparatus, method, and computer program product for handling such conflicts and thereby enhancing the effectiveness of the events-notification activity. An alternative embodiment of this solution handles the scenario where multiple networks having multiple clients sharing particular servers create template name/content conflicts.
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BACKGROUND OF THE INVENTION
The invention relates to artificial mechanical hands, and more particularly to an improved mechanical hand with multiple prehension capability, especially suitable for bilaterals, or double amputees.
For unilaterals, or single amputees, a mechanical hand often takes the form of a simple split hook of the type shown, for example, in U.S. Pat. No. 1,042,413. This type of artificial hand unusually has a spring or elastic band urging the two hook sections together to grasp objects between them, with the sections openable by the action of a cable attached to a body harness. Another example of this type of artificial hand is shown in U.S. Pat. No. 1,206,753.
Bilaterals, with no natural hand for the more difficult grasping functions, need artificial hands with more complete prehension capability than is afforded by the hook described above. A number of more complex artificial hand mechanisms have been suggested, as shown for example in U.S. Pat. Nos. 2,422,530, 2,487,724, 2,409,884, 2,853,711, 3,413,658, and 4,016,607.
The disadvantages of these prior art devices have been that they are either too complicated to be economically feasible, they have been difficult to learn to operate, they have failed to provide important types of prehension capability, or they have been oriented so much toward cosmetic appeal that they necessarily have been very limited in functional advantages.
None of the devices shown in the prior patents provides the degree of prehensile versatility, with the simplicity of construction and operation, as does the present invention described below.
SUMMARY OF THE INVENTION
The artificial hand of the present invention facilitates a combination of important prehension functions in one relatively simple apparatus, operable by a standard sheathed cable connected to a body harness known in the prior art. The hand enables the user to grasp rounded objects such as doorknobs and to easily turn a doorknob, to grasp objects between a finger tip and a thumb, and to grip small or thin objects with an auxiliary finger which forms a line of contact with the flat surface of the thumb. The fingers are urged by a spring toward their open position away from the thumb, and cable tension is effective to close the fingers towards the thumb in a powerful grip. Many prior art mechanical hands worked oppositely, with a spring providing the pressure to close the gripping mechanism and the cable merely opening it.
When cable tension is put to the hand of the invention, the finger tip of a main finger first comes into contact with the relatively stationary thumb. Continued additional tension brings the auxiliary, straight finger into a line of contact with the thumb; and still further cable retraction pivots the entire closed hand, fingers and thumb, downward along a wrist pivot axis, to a position where the hand would be usable for reaching into a breast pocket, for example.
The thumb of the artificial hand preferably is split into two components, one of which is pivotable toward and away from the other. This is for prepositioning the openable thumb portion for functions such as gripping doorknobs, where three points of contact are desirable for a stable grip.
In a preferred embodiment, an artificial hand according to the present invention comprises a support base for connecting to the arm of the user, with a wrist connected to the base and a pivot axis in the wrist. A pivotal main finger is connected along the pivot axis to the wrist, with a downwardly angled finger tip at its ends. Alongside the main finger is a generally straight pivotal finger, also connected along the pivot axis to the wrist and normally in a position spaced angularly back of the finger tip of the main finger, so that the finger tip leads the straight finger as the two fingers are moved downwardly. A thumb extends from the wrist, positioned to be contacted by the fingers in their downward, closed position. Means are provided in association with the main finger and the thumb for enabling grasping of rounded objects between them. There are provided a control cable and cable housing adapted for connection to typical harness apparatus worn on the body of the user, with means connecting the forward end of the cable housing to the thumb and means connecting the forward end of the cable, extending from the housing, to the fingers in such a way that retraction of the cable in the housing pulls the fingers toward the thumb, first contacting the main finger tip with the thumb and then bringing the straight finger toward contact with the thumb on further retraction of the cable. A means is provided for biasing the main finger and the straight finger away from the thumb to their normal open position.
Accordingly, it is among the objects of the invention to provide an improved artificial, mechanical hand capable of fulfilling the needs of bilaterals and providing for multiple forms of prehension from a simple, single-cable actuation system. Other objects, advantages and features of the invention will be apparent from the following description of some preferred embodiments, considered in connection with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing an artificial hand according to the invention, connected to a prosthetic device at the end of the arm of a user. The hand illustrated is a right hand.
FIG. 2 is a left side elevational view of the hand of FIG. 1.
FIG. 3 is a detailed, partially sectioned view showing a resilient insert in the tip of a finger of the artificial hand.
FIG. 4 is a bottom view of the artificial hand.
FIG. 5 is a sectional view showing the connection of several relatively movable components of the artificial hand of the invention.
FIG. 6 is an exploded view in perspective of the artificial hand.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, FIG. 1 shows an artificial hand 10 according to the invention, preferably employed as a right hand because of the location of a cable and sheath 11 and 12 and the orientation of certain other components.
The hand 10 includes a support base 13 with some form of connection such as a threaded stud 14 for securing to a prosthetic device 16 attached to the arm of the user. Preferably, the support base 13 has a forward extending flange or wrist 17 as shown, from which a main finger 18, a straight finger 19 and a thumb 21 are pivotally supported along a wrist pivot axis 22. A threaded shaft 23 (see also FIG. 6) is advantageously used for supporting the fingers 18 and 19 and the thumb 21 along the axis 22, and nuts 24 at either end and may be employed to retain the assembly together.
The position of the aritifical hand shown in FIGS. 1 and 2 is the normal position. The main finger 18 and the straight finger 19 are biased toward the open position by a spiral spring 26 on the left side of the hand (see FIGS. 2 and 6), secured to the threaded shaft 23 by a slot 23a shown in FIG. 6 and in engagement with a stud pin 27 which extends from the straight finger 19 through an elongated, slot-shaped opening or window 28 of the main finger to its connection with the spring 26 as shown in FIG. 2. The stud 27 and the window 28 are so positioned that both the fingers 18 and 19 receive the force of the spring 26 when the fingers are both in the normal open position shown in FIGS. 1 and 2. However, the straight finger 19 is permitted a small degree of movement downward relative to the main finger 18, while still being under the influence of the spring 26, tending to urge it toward the full open position. The purpose and function of the arrangement will be explained below.
Limitation of upward, opening movement of the fingers 18 and 19 is provided by a stud 29 forming a stop against which an abutment 31 engages (see FIGS. 2 and 6). This limits upward pivotal movement of the main finger 18, since the abutment 31 is on this finger, and also limits movement of the straight finger 19 in the same direction, since the stud 27 extends from the finger and is stopped by the boundary of the window 28 in the main finger.
The cable 11 and sheath 12 are adapted for connection to a standard body harness (not shown) for operation of mechanical hands, with appropriate means connected to the shoulder for pulling the cable 11, retracting it within its sheath 12, which is braced at another point, such as the upper arm. Retraction of the cable moves the two fingers downwardly with respect to the thumb 21, to which the end of the sheath 12 is anchored as shown. The end of the cable 11 is attached to a link 32, which is pivotally connected at spaced locations 33 and 34 to each of the straight finger 19 and the main finger 18, respectively. The link 32, and its connection 36 with the end of the cable 11, are so positioned that retraction of the cable 11 first pulls the main finger 18 downwardly toward the thumb, until it reaches contact with the thumb as illustrated in dashed lines in FIG. 2 with the main finger 18a and the straight finger 19a. The straight finger remains in its normal position with respect to the main finger during this retraction, and objects can be grasped between a tip 37 of the main finger and the thumb, or between a concavely curved portion 38 of the main finger and the thumb.
However, if the cable 11 is retracted further when the fingers are in the positions 18a and 19a shown in FIG. 2, the straight finger 19a will be urged by the pivotal cable link 32 further downwardly, independent of the main finger, until it meets the thumb at a position 19b shown in dashed lines in FIG. 2. This enables the grasping of small, long objects, such as a pencil. In this position both the fingers are urged against the surface of the thumb 21 by the force applied by the cable 11 through the link 32. Only the straight finger 19 is acted upon by the spring 26 in this position, since the stud 27 extending from the straight finger will be at the lower end of the window 28.
When the cable 11 is released, the spiral spring 26 would tend to pull the straight finger back to its position 19a shown in FIG. 2, before the main finger 18 leaves the position 18a shown in FIG. 2. However, in some circumstances it is desirable that the straight finger remain extended, substantially flush with the finger tip 37 of the main finger, during the initial part of the retraction. This is desirable, for example, when the hand is to be inserted in a pocket and the straight finger 19 might snag on the pocket if in its normal position with respect to the main finger 18. Therefore, a tension spring 39 is positioned as shown on the left side of the hand 10, secured to the outside of the main finger 18 and connected to the stud 27 of the straight finger, tending to move the straight finger 19 toward the position 19b shown in FIG. 2 relative to the main finger 18. The force of the spring 39 is considerably lighter than that of the spiral spring 26, but sufficient to partially counterbalance the spring 26 during the initial release of the cable 11, so that the two fingers 18 and 19 do not assume their normal positions relative to one another until they have both moved somewhat away from the thumb 21.
The normal position of the thumb 21 on the wrist or flange 17 is shown in FIGS. 1 and 2 in solid lines. However, the thumb 21, like the fingers 18 and 19, is pivotal along the axis 22. To hold it in the normal, generally straight forward position shown in the figures, a friction washer 41 is positioned between the thumb 21 and the wrist 17, as best seen in the exploded view of FIG. 6. Thus, with a prescribed degree of tightness of the nuts 24 on the threaded shaft 23, the thumb is held in its normal position while the fingers freely rotate along the axis 22.
When desired, the thumb can be moved manually or "prepositioned" to a downwardly pivoted condition, as shown in dashed lines in FIG. 2, with the thumb shown at 21b. The user does this prepositioning by reaching his arm out beyond the point where the fingers contact the thumb, to retract the cable even further. This pulls the thumb to the downwardly pivoted position 21b.
This positioning of the hand is desired, for example, when the user wishes to reach into a breast pocket. Once in this position the fingers and thumb can be used in the normal way, by retraction of the cable 11. When the thumb and fingers are to be returned, the thumb is simply pushed back to its normal position by pushing against a stationary object or against a part of one's body such as a leg, etc. The fingers stay in the same relative position with respect to the thumb (as in FIG. 1), because of the stop and abutment 29 and 31 acting between the thumb 21 and the main finger 18. The normal position is defined as shown in FIG. 1 by a rear portion 21a of the thumb engaging against a forward bottom surface 17a of the wrist 17.
To aid in the manual return of the thumb to the normal position, there may be provided a second spiral spring 42 on the right side of the hand as shown in FIGS. 1 and 6. This spring engages against a stud 43 on the wrist flange 17 and acts on the threaded shaft 23 (via a slot 23b shown in FIG. 6), which preferably is connected to the thumb 21 to urge the shaft 23 and thumb 21 toward the normal position. Friction between the wrist 17 and thumb 21 is preferably sufficient to maintain the thumb in whatever position the user prepositions it, but the spring enables it to be returned with a lighter force.
FIG. 3 shows a resilient tip 44 on the finger tip 37, which may be a replacable element inserted into the finger tip as shown. This enables better grasping of objects between the finger tip and thumb.
As shown in the drawings, particularly FIG. 6, the thumb 21 is made up of several components. A rearward or base portion 21c of the thumb is affixed to the threaded shaft 23, and this may be integral with a stationary portion 21d of the thumb, or it may be affixed thereto by fasteners 46, as shown. The thumb may also include a movable portion 21e, pivotal along a generally vertical axis 47 (FIG. 6) with respect to the remainder of the thumb. This enables the movable portion 21e to swing away from the stationary portion 21d as indicated in dashed lines in FIGS. 1 and 4.
When the thumb portions 21d and 21e are closed, i.e. in their normal position, and the main finger 18 is brought down to the thumb, the finger tip 37 (i.e. the resilient insert 44) engages against the movable portion of the thumb 21e. The straight finger 19 comes down adjacently and engages against the surface of the stationary thumb portion 21d. When the movable thumb portion 21e is opened, by manual prepositioning, the main finger 18 then converges toward the space between the two thumb portions. This provides a three-point set of gripping contacts for engaging thick or rounded objects, particularly those which are to be turned such as doorknobs. A rubber or resilient type surface 48 preferably is included on both thumb portions for better gripping of objects, and this aids considerably in the gripping of rounded objects.
The movable thumb portion 21e may be connected to the thumb base portion 21c by a threaded fastener 49, as best seen in FIGS. 4 and 6. It is maintained in the normal position or the open position by a ball and detent arrangement. As indicated in FIG. 6, this may include a spring 51 urging a ball 52 downwardly from a bore (see FIG. 2) in the portion 21c, for engagement with either of two detents 53 and 54 in the upper surface of the movable thumb portion 21e.
As indicated in broken lines in the bottom view of FIG. 4, a tension spring 55 may be included to urge the movable thumb portion 21e toward the closed position, the spring not being sufficiently strong to overcome the holding action of the ball and detent.
When the thumb portions 21d and 21e are separated, as shown in dashed lines in FIGS. 1 and 4, the hand is sometimes used to pick up heavy objects. For this purpose it is necessary to keep the thumb 21 in the normal position, preventing it from pivoting downwardly (as shown at 21b in FIG. 2). Therefore, a special feature is provided for acting between the movable thumb portion 21e and the wrist 17. As best seen in the bottom view of FIG. 4, this arrangement comprises a stud 56 extending downwardly from the bottom of the wrist 17 and a boss 57 which is clear of the stud 56 in the closed position of the thumb but directly in the path of the stud 56 when the movable thumb portion 21e is pivoted outwardly as shown in dashed lines in FIG. 4. This provides a stop against downward movement of the thumb assembly, even when heavy weights are lifted.
There are several additional features which give the artificial hand of the invention additional versatility, particularly for bilaterals who have no natural hand to supplement the use of the mechanical hand. One such feature is a groove 60 in the side of the finger tip 37 of the curved main finger 18, as shown in FIGS. 2 and 6. The groove 60 can be used to catch an edge of a small object, and the narrow portion of the finger below the groove, between the groove and the tip, enables the user to lift the edge of a small object such as a pop top seal on a can of liquid refreshment, and from there he is able to grasp the object between the pliable finger tip pad 44 and the thumb 21.
As shown in the bottom view of FIG. 4, grooves 61 or other textured surfacing preferably are included in the bottom surface of the movable thumb portion 21e, to aid the user in prepositioning the thumb to the open position.
At the top surface of the movable thumb portion 21e as shown in FIGS. 1 and 6, there may be included a metal corner area 62, in the surface otherwise covered with the resilient high-friction surface material 48. This is helpful in picking up small objects in instances where the resilient material 48 might actually hinder the grasping of the object between the finger tip 37 and the thumb portion 21e.
As indicated in the drawings, the straight finger 19, which converges down onto the non-pivotal thumb portion 21d in a line of contact just adjacent to the separation of the two thumb portions 21d and 21e, may also include a resilient surface strip 63. This further aids in gripping objects or sheet materials such as papers.
An additional feature that preferably is included in the artificial hand 10 of the invention for both aesthetic and functional reasons is a pair of protective cups 65 appropriately secured to the outside of the wrist 17 on the one side and of the main finger 18 on the other side, as shown in FIGS. 1, 2, 4 and 6. These cups 65 improve the appearance of the hand, hiding the springs 42, 26 and 39 and the other hardware associated with them, and also cover these components to prevent their catching or snagging on clothing or other objects.
It should be understood that other features of the artificial hand of the invention may be modified to present a more aesthetic appearance--the fingers may be modified to appear more like human fingers, and the thumb may also be made to appear more like the human. Preferably, these changes are made in such a way as to maintain the functionality of the hand and to avoid excessive cost of manufacture.
It should also be understood that certain modifications can be made to the function of the hand shown in the drawings, without departing from the scope of the invention. For example, the principal purpose of the two-component pivotal thumb is to provide a three-point contact for certain types of gripping, such as doorknobs and other rounded or thick objects. This can be accomplished, for some applications, by simply providing a shaped thumb capable of providing two points of contact without any prior prepositioning movement, the third point of contact being made by the main finger 18. The illustrated split thumb, however, is preferred.
Similarly, for some applications it may be desirable to eliminate the straight finger 19, including the main finger 18 as the only finger converging toward the thumb. For example, if the artificial hand is to be used by a unilateral amputee, rather than a bilateral, or if it is for a bilaterial having a complete artificial hand 10 as illustrated in the drawings as one hand, the other hand may be of a somewhat simplified version, perhaps without the straight finger 19.
It should be further understood that the split thumb, as provided, can take other forms from that shown in the drawing. For example, it may be formed with the portions 21d and 21e both swingable away from one another, rather than the simpler arrangement illustrated wherein only one portion is movable.
Other embodiments and variations to the illustrated preferred embodiment will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the invention as defined in the following claims.
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An artificial hand has a stationary wrist and two fingers and a thumb pivotal from a horizontal axis in the wrist. The thumb may have two separable portions, one of which is pivotal away from the other along a generally vertical axis by manual prepositioning. This enables rounded objects such as doorknobs to be grasped by the curved main finger and the two thumb portions, making stable three-point contact. The two fingers are pivotal along the wrist axis in a fixed range of motion with respect to the thumb, and a spring urges the fingers toward a normal open position. Tension of a sheathed cable fitted to a standard body harness closes the fingers to the thumb, enabling a powerful grip. The second finger is straight and normally remains alongside the curved finger until, upon closure of the curved finger and contact to its tip with the thumb, further cable tension closes the straight finger against the thumb to grip small or flat, thin objects. A special link between the cable and the fingers is provided for this purpose.
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FIELD OF THE INVENTION
[0001] This invention relates generally to emission control valves that are used in emission control systems associated with internal combustion engines in automotive vehicles. The invention particularly relates to force-balance and anti-coking improvements in exhaust gas recirculation (EGR) valves.
BACKGROUND OF THE INVENTION
[0002] Controlled engine exhaust gas recirculation is a known technique for reducing oxides of nitrogen in products of combustion that are exhausted from an internal combustion engine to atmosphere. A typical EGR system comprises an EGR valve that is controlled in accordance with engine operating conditions to regulate the amount of engine exhaust gas that is recirculated to the fuel-air flow entering the engine for combustion so as to limit the combustion temperature and hence reduce the formation of oxides of nitrogen.
[0003] Because they are typically engine-mounted, EGR valves are subject to harsh operating environments that include wide temperature extremes and vibrations. Tailpipe emission requirements impose stringent demands on the control of such valves. An electric actuator, such as a solenoid that includes a sensor for signaling position feedback to indicate the extent to which the valve is open, can provide the necessary degree of control when properly controlled by the engine control system. An EGR valve that is operated by an electric actuator is often referred to as an EEGR valve.
[0004] When an engine with which an EEGR valve is used is a diesel engine, further considerations bear on the valve. Because such engines may generate significantly large pressure pulses, attainment of acceptable control may call for the use of a force-balanced EEGR valve so that any influence of exhaust gas pressure on valve control is minimized, and ideally completely avoided. For example, a large pressure pulse should not be allowed to force open an EEGR valve that is being operated to closed position by the solenoid.
[0005] A double-pintle type valve can endow an EEGR with a degree of force balance that is substantial enough to minimize the influence of exhaust gas pressure on valve control, for example minimizing the risk that large exhaust pressure pulses will open the EEGR valve when the engine control strategy is calling for the valve to be closed. A double-pintle type valve allows the valve to have a split-flow path where each pintle is associated with a respective valve seat. Such a valve can handle larger flow rates with a degree of control suitable for control of EGR.
[0006] Because of various factors that bear on an EEGR valve's ability to control tailpipe emissions for compliance with relevant regulations, including considerations already mentioned, construction details of a double-pintle EEGR valve become important. Individual parts must be sufficiently strong, tightly toleranced, thermally insensitive, and essentially immune to combustion products present in engine exhaust gases.
[0007] Certain combustion products in engine exhaust gases may tend to deposit on certain surfaces of certain parts of an EEGR valve. This phenomenon is sometimes called “coking”, and it can be detrimental to valve performance.
[0008] For example, when an EEGR valve pintle is unseated from its seat to allow exhaust gas flow through an annular space between the outer perimeter of the pintle and the inner perimeter of the seat, surface zones of the perimeter margins of both pintle and seat become exposed to exhaust gas flow. Depending on the particular design of the pintle-seat interface, deposits may form on those zones. The nature of the deposited material may cause a pintle to stick to some extent on the seat when the pintle is closed, and that can interfere with proper valve operation. For example, when the valve is to re-open, sticking may require extra force to unseat the pintle, particularly when the valve is cold. The presence of such material can also interfere with proper pintle re-seating on the seat, possibly resulting in leakage through the valve when the pintle should seat fully closed on the seat.
[0009] Constructing one or the other of the pintle and the seat to have a sharp corner, 90° for example, rather than a flat angled surface that makes contact with a similarly angled surface of the other when the valve is closed, tends to resist the depositing of material at and near the corner. However, the degree of sharpness of such a corner may complicate the process of making the part containing the edge. For example, machining a seat to create circular edge having a sharp 90° corner that is intended to seat on a frustoconical surface of a pintle may require an operation, such as de-burring, to assure that no imperfections, such as burrs, are present in the edge. Such an edge may be prone to nicking, also undesirable.
[0010] In mass-production automotive vehicle applications, the cost-effectiveness of the construction of a component, such as an EEGR valve, is important, and so it is desirable to avoid extra processing operations in the manufacture of such a component whenever possible.
SUMMARY OF THE INVENTION
[0011] The present invention relates to certain improvements in the construction of an EEGR valve, such as a double-pintle EEGR valve, particularly improvements in the pintle-seat interfaces.
[0012] One improvement is directed to an interface that tends to discourage the deposit of materials from the exhaust gases passing through the valve on surfaces at the interface so that proper performance of an EEGR valve can continue during its useful life free of deposits at the interface that might otherwise seriously impair acceptable valve performance.
[0013] Another improvement is directed to better force-balancing of the pintle in a double-pintle EEGR valve for minimizing the influence of exhaust pressure fluctuations on valve operation. The conjunction of these improvements in an EEGR valve can contribute to better valve performance and longer useful life of an EEGR valve in an exhaust emission control system of a diesel engine, and with cost-effectiveness.
[0014] A general aspect of the invention relates to an emission control valve for use in an emission control system of an internal combustion engine. The valve comprises valve body structure providing an inlet port at which flow enters the valve and an outlet port at which flow exits the valve. A valve element comprises first and second closures spaced apart along an axis for respective cooperation with respective seats that are axially spaced apart to selectively seat on the respective seat for disallowing flow between the inlet port and the outlet port and to unseat from the respective seat for allowing flow between the inlet port and the outlet port. An actuator selectively positions the valve element along the axis relative to the seats.
[0015] Each seat circumscribes a respective through-hole for flow. The through-hole of one seat is large enough diametrically to allow the closure that seats on the other seat to pass through during fabrication of the valve. Each through-hole comprises a respective frustoconical surface zone coaxial with the axis and tapered in the same axial direction. The closure that seats on the other seat seats on a radially outermost portion of the frustoconical surface zone of the through-hole of the other seat when the valve element is disallowing flow, and the other closure seats on a radially innermost portion of the frustoconical surface zone of the through-hole of the one seat when the valve is disallowing flow.
[0016] Another general aspect relates to an exhaust gas recirculation system having such a valve.
[0017] The accompanying drawings, which are incorporated herein and constitute part of this specification, include one or more presently preferred embodiments of the invention, and together with a general description given above and a detailed description given below, serve to disclose principles of the invention in accordance with a best mode contemplated for carrying out the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is an elevation view of an EEGR valve embodying principles of the invention.
[0019] FIG. 2 is a left side elevation view of FIG. 1 .
[0020] FIG. 3 is an enlarged cross section view in the direction of arrows 3 - 3 in FIG. 1 .
[0021] FIG. 4 is an elevation view of one part of the valve by itself, that part being a double-pintle.
[0022] FIG. 5 is a cross section view in the direction of arrows 5 - 5 in FIG. 3 .
[0023] FIG. 6 is an elevation view of another part of the valve by itself, that part being a seat element having a double-seat.
[0024] FIG. 7 is a right side elevation view of FIG. 6 .
[0025] FIG. 8 is a rear elevation view of FIG. 6 .
[0026] FIG. 9 is a top plan view of FIG. 8 .
[0027] FIG. 10 is a cross section view in the direction of arrows 10 - 10 in FIG. 8 , but including the pintle.
[0028] FIG. 11 is an enlarged fragmentary view of a portion of FIG. 10 showing a modification.
[0029] FIG. 12 is an enlarged fragmentary view of another portion of FIG. 10 showing a modification.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0030] FIGS. 1-3 illustrate the general arrangement and organization of an exemplary EEGR valve 20 embodying principles of the present invention. Valve 20 comprises a base 22 and an elbow 24 assembled together to form a flow path 26 through the valve between an inlet port 28 provided in a flange at a side of base 22 and an outlet port 30 provided in a flange at one end of elbow 24 .
[0031] Base 22 is a metal part that has a main longitudinal axis 32 . Base 22 may be considered to have a generally cylindrical shape about axis 32 comprising a generally cylindrical wall bounding an interior space that is open at opposite axial end faces of the base. Base 22 is constructed so that its interior space is also open to inlet port 28 .
[0032] An end of elbow 24 that is opposite the end containing outlet port 30 is fastened in a sealed manner to the lower end face of base 22 so that the interior of elbow 24 is open to the interior space of base 22 . A cover 34 is fastened in a sealed manner to the upper end face of base 22 to close that end of the interior space of base 22 while providing a platform for the mounting of an electric actuator 36 on the exterior of the cover.
[0033] Actuator 36 comprises a solenoid that, when the valve is installed on an engine in a motor vehicle, is electrically connected via an electric connector 38 (shown out of position in FIG. 3 ) to an electrical system of the motor vehicle to place the valve under the control of an engine controller in the vehicle.
[0034] A bearing 40 is centrally fit to cover 34 such that a guide bore of the bearing is coaxial with axis 32 . Bearing 40 serves to axially guide a double-pintle 42 (shown by itself in FIG. 4 ) of valve 20 along axis 32 via a guiding fit of the bearing guide bore to an upper portion of a stem 44 of double-pintle 42 that extends completely through the bearing guide bore from an armature of the solenoid into the interior space of base 22 where upper and lower pintles 46 , 48 are disposed on stem 44 .
[0035] A double-seat element 50 shown by itself in FIGS. 6-9 is fit to base 22 within the latter's interior space. Element 50 is a machined metal part that has a generally cylindrical shape. It comprises a generally cylindrical wall 52 that is coaxial with axis 32 in valve 20 and that is open at opposite axial ends. Element 50 comprises axially spaced apart upper and lower seats 54 , 56 (see FIG. 10 ) with which pintles 46 , 48 respectively cooperate. Wall 52 comprises two pairs of openings, or apertures: an upper pair 58 , 60 , and a lower pair 62 , 64 . The lower pair are arranged axially between seats 54 , 56 to provide for the open interior of element 50 that is circumscribed by wall 52 between seats 54 , 56 to communicate through the opening in base 22 to inlet port 28 . The upper pair 58 , 60 are arranged axially beyond seat 54 relative to the lower pair 62 , 64 to provide for the open interior of element 50 that is circumscribed by wall 52 beyond upper seat 54 to communicate with respective entrances to an internal passageway 66 (see FIG. 5 ) than runs within base 22 internally through a portion of the generally cylindrical wall of the base that is in the semi-circumferential portion of that wall opposite inlet port 28 .
[0036] The outside diameter surface of wall 52 is stepped, comprising zones of successively larger diameter from bottom to top so as to allow element 50 to be assembled to base 22 by inserting element 50 into the interior space of base 22 through the opening in the upper end face of the base. The smallest outside diameter zone of wall 52 is at the bottom of element 50 essentially coextensive with seat 56 . The next larger diameter zone is the one containing apertures 62 , 64 , and at the juncture of those two zones is a chamfered shoulder 68 .
[0037] The next larger diameter zone is the one containing apertures 58 , 60 , and at its juncture with the zone containing apertures 62 , 64 , there is a raised circular ridge 70 having an inclined surface 72 that wedges with a portion of the inside diameter of the cylindrical wall of base 22 when element 50 is assembled to the base. The uppermost zone of wall 52 comprises a circular lip 76 on the outside and a shoulder on the inside.
[0038] When element 50 is assembled to base 22 , the zone of wall 52 containing apertures 62 , 64 fits to the circular inside diameter surface of the wall of base 22 in an orientation about axis 32 that places apertures 62 , 64 in registration with inlet port 28 , as shown in FIG. 2 . Thereafter, a sub-assembly of cover 34 , bearing 40 , and actuator 36 are assembled to base 22 at the upper end face of the base by fastening the cover to the base. Before elbow 24 is placed on the lower face of base 22 , double-pintle 42 is assembled into the valve through the open lower end face of the base. Stem 44 passes through the guide bore in bearing 40 and into the interior of the actuator where it attaches to the solenoid armature. With the solenoid not being energized, each of the two pintles 46 , 48 seats on a respective seat, closing the respective opening, or through-hole, circumscribed by the respective seat. The armature is spring-biased to urge the pintles against the seats with an appropriate amount of force.
[0039] It can be appreciated that the outside diameter of upper pintle 46 is less than that of the through-hole circumscribed by lower seat 56 so that the former can pass through the latter during assembly of the double-pintle into the valve. Thereafter elbow 24 is fastened to base 22 to complete the assembly.
[0040] Valve is substantially force-balanced because of the particular double-pintle design. When inlet port 28 is communicated to the engine exhaust system so that hot engine exhaust gases can enter the valve, the pressure of those gases acting on the pintles creates forces that are substantially equal in magnitude, but in opposite directions along axis 32 , although the upward force acting on pintle 48 will have a slightly larger magnitude than the downward one acting on pintle 46 . Hence, pressure pulses will at most have a very minor, and ideally negligible, effect on the positioning of double-pintle 42 by actuator 36 . This is important for control accuracy.
[0041] For the accurate handling of flow within a rather large range of flow rates, it is also important that the internal construction of the valve be substantially immune to the effects of exhaust gas constituents, exhaust gas temperature extremes, and exhaust gas pressure extremes. Parts that are important to control accuracy need strict manufacturing tolerances. Restriction of the flow path through the valve should be determined by the positioning of the valve element in relation to the valve seat, meaning that the design of other parts of the valve that define the flow path should impose a restriction that is essentially negligible when compared to the restriction between the valve element and the valve seat.
[0042] These objectives are best met by rigid metal parts that can be machined to the required dimensional accuracy. A double-pintle valve, as described, splits the entering exhaust gas flow so that the flow divides more or less equally as it passes through seat element 50 . Ideally there should be essentially no restriction to the incoming flow entering the seat element from inlet port 28 . For maximizing the cross sectional area through which the incoming flow enters seat element 50 , the circumferential span of the opening in the wall of seat element 50 should be essentially its semi-circumference. Collectively, apertures 62 , 64 do just that. But in order to minimize the wall thickness of the seat element while retaining the necessary degree of strength, rigidity, and dimensional accuracy of the seat element, the seat element is a machined part where the two apertures 62 , 64 are separated by a narrow axial bar 80 in the wall, rather than being a single aperture having a like semi-circumferential span. Similarly, apertures 58 , 60 are separated by a somewhat wider bar 84 .
[0043] FIG. 10 shows the closed condition with each pintle 46 , 48 seated on the respective seat 54 , 56 . Seat 54 circumscribes a circular through-hole defined by a circular cylindrical surface zone 54 A both parallel and coaxial with axis 32 and a frustoconical surface zone 54 B that extends from a circular edge 54 C at its junction with zone 54 A coaxial with axis 32 in the direction toward the space circumscribed by wall 52 between the two seats. The cone angle of zone 54 B is 30° in this particular embodiment. Zone 54 B ends at a flat surface zone 54 D that is perpendicular to axis 32 . The geometric relationship between zones 54 B and 54 D endows the seat with an obtuse-angled circular corner edge 54 E against which a frustoconical surface 46 A of pintle 46 seats when valve 20 is closed. Surface 46 A has a cone angle of 42° in this particular embodiment.
[0044] Seat 56 circumscribes a circular through-hole defined by a circular cylindrical surface zone 56 A both parallel and coaxial with axis 32 and a frustoconical surface zone 56 B that extends from an obtuse-angled circular corner edge 56 C at its junction with zone 56 A coaxial with axis 32 in the direction away from the space circumscribed by wall 52 between the two seats. Zone 56 B ends at a flat surface zone 56 D that is perpendicular to axis 32 . The cone angle of zone 56 B is 60° in this particular embodiment. A frustoconical surface 48 A of pintle 48 seats on corner edge 56 C when valve 20 is closed. Surface 48 A has a cone angle of 42° in this particular embodiment.
[0045] So that double-pintle 42 can be assembled into the valve, the diameter of zone 56 A is made larger than the largest outside diameter of pintle 46 , with an appropriate amount of radial clearance to facilitate assembly. The largest outside diameter of pintle 46 occurs in a circular cylindrical portion that extends axially from frustoconical surface 46 A.
[0046] When each pintle is seated on the respective seat as shown in FIG. 10 , the obtuse-angled corner edge 54 E at the junction of seat surface zones 54 B, 54 d makes essentially circular line edge contact with surface 46 A of pintle 46 , and the obtuse-angled corner edge 56 C at the junction of seat surface zones 56 A, 56 B makes essentially circular line edge contact with surface 48 A of pintle 48 .
[0047] With the smallest diameter portion of the through-hole in seat 56 contacting pintle 48 and the largest diameter portion of the through-hole in seat 54 contacting pintle 46 , greatest correspondence between the effective areas of the two pintles on which exhaust gas pressure acts is attained, maximizing the extent of force-balance. The effective areas have respective diameters of 25.1 centimeters and 26.0 centimeters in this example.
[0048] At the same time, the geometries of the respective seat-pintle interfaces tend to discourage deposit of certain exhaust gas constituents at the interfaces. With the valve just slightly open, exhaust gas flowing through seat 54 is increasingly constricted between surfaces 54 D, 46 A as it approaches the point of maximum restriction at the obtuse-angled corner edge 54 E, but once past that corner edge, the flow is allowed to expand as it passes between surfaces 54 B, 46 A.
[0049] The same is true at the other seat-pintle interface where the flow is increasingly constricted as it approaches corner edge 56 C, and then once past corner edge 56 C, it is allowed to expand due to the angular relationship between surfaces 48 A, 56 B.
[0050] FIGS. 11 and 12 show respective modifications to seats 54 and 56 in another example. The drawings are exaggerated for clarity of illustration. Edge 54 E has a slight chamfer 54 F instead of being sharp. The cone angle of the chamfer is slightly larger (1° larger in the example) than the cone angle of surface 46 A. Similarly, edge 56 C has been modified to includes a slight chamfer 54 E, whose cone angle is also 1° larger than the cone angle of surface 48 A. It is believed that the inclusion of the chamfers can improve durability and performance.
[0051] Anti-coking features are embodied in the pintle-seat interfaces because of the geometries that have been described. A seat having an obtuse corner with a sharp edge or alternately a slightly chamfered one, as shown and described, makes substantial circular edge contact with a frustoconical surface zone of the corresponding pintle. When the valve is operated just slightly open, the flow is increasingly constricted as it approaches the corner edge. Once past the corner edge, the flow is allowed to expand due to the angular relationship between the seat and pintle surface zones.
[0052] While the foregoing has described a preferred embodiment of the present invention, it is to be appreciated that the inventive principles may be practiced in any form that falls within the scope of the following claims.
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A double-pintle valve ( 20 ) has two seats ( 54, 56 ) each circumscribing a respective through-hole for exhaust gas flow. The through-hole of one seat ( 56 ) is large enough diametrically to allow the closure ( 46 ) that seats on the other seat ( 54 ) to pass through during fabrication of the valve. The closure ( 46 ) seats substantially on a radially outermost portion of a frustoconical surface zone ( 54 B) of the seat ( 54 ) and the other closure ( 48 ) seats substantially on a radially innermost portion of a frustoconical surface zone ( 56 B) of the one seat ( 56 ) when the valve is disallowing flow.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional application No. 60/249,137, filed on Nov. 16, 2000, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to drawer slides and more particularly to a telescopic frictional drawer slide.
[0003] Telescopic slides for file drawers and the like are often desirable for use in cabinets and other rack mounted applications. Such slides permit easy access to the interior of the drawer. The slides maintain the drawer in a horizontal position regardless of how far the drawer is withdrawn from the cabinet. The slides are also useful in the mounting of extendable shelves and cabinets. A typical drawer will often have two slides securing the drawer to the cabinet or enclosure, with the slides attached to each of the outside vertical walls of the drawer.
[0004] Frictional drawer slides typically have members that rub against each other in sliding engagement. One advantage of frictional drawer slides is that there are no ball bearings. One disadvantage of typical frictional drawer slides is noise of operation. Another disadvantage of typical frictional drawer slides is difficulty in opening because of a large amount of friction, especially after wear.
SUMMARY OF THE INVENTION
[0005] A telescopic drawer slide according to an embodiment of the present invention includes first, second and third drawer slides each having a longitudinal length with a web, and arms along the longitudinal margins of the web. The second drawer slide is nested within the arcuate arms of the first drawer slide. The third drawer is nested within the arcuate arms of the second drawer slide. The telescopic drawer slide has a lock between the second drawer slide and the first drawer slide, the lock having a biased tab rotatably coupled to the second drawer slide and an emboss on the first drawer slide. The tab moves into a portion of the emboss upon movement over the emboss, thereby preventing the second drawer slide from closing relative to the third drawer slide.
[0006] In an embodiment, the tab is biased by gravity. In an alternative embodiment, the tab is biased by a spring. The tab is moved over the emboss by the third drawer slide thereby allowing the second drawer slide to close relative to the first drawer slide after closing of the third drawer slide relative to the second drawer slide.
[0007] In an embodiment, the emboss has an angled portion tapering toward the arcuate arms of the first drawer slide, a wide portion with longitudinal edges, and an edge leading to a narrow portion. As the second drawer slide is withdrawn from the first drawer slide, the tab moves to the narrow portion and is restrained by the edge from closing.
[0008] The web of the second drawer slide has a hat section extending along the longitudinal length. The hat section of the second drawer slide clearing the emboss on the first drawer slide. The web of the third drawer slide has a hat section extending along the longitudinal length. The hat section of the third drawer slide clearing and surrounding the hat section of the second drawer slide.
[0009] In an embodiment, the arms of the first drawer slide have a lateral portion that is bowed toward the arms of the second drawer slide. The arms of the second drawer slide are nested within the arms of the first drawer slide defining a contact area along a tip of the bowed portion of the arms and a reservoir adjacent to the contact area.
[0010] In another additional embodiment, the arms of the third drawer slide have a lateral portion that is bowed toward the arms of the second drawer slide. The arms of the third drawer slide are nested within the arms of the second drawer slide defining a contact area along a tip of the bowed portion of the arms of the third drawer and a reservoir adjacent to the contact area.
[0011] In an additional embodiment, the telescopic drawer slide has a lock between the third drawer slide and the second drawer slide. The lock has a biased tab on the third drawer slide and a hole in the second drawer slide. The biased tab enters the hole when the third drawer slide is withdrawn from the second drawer slide.
[0012] In an alternative embodiment, the lock between the third drawer slide and the second drawer slide has a biased arm with a cutout rotatably coupled to the third drawer slide and a tab on the second drawer slide oriented toward the third drawer slide. The tab enters the cutout as the third drawer slide is withdrawn from the second drawer slide. In an additional embodiment, a lock release moves the biased arm to move the cutout away from the tab.
[0013] Additionally, a telescopic drawer slide according to an embodiment has a stop between the second drawer slide and the first drawer slide. A portion of the web of the second drawer slide is punched toward the first drawer slide and a portion of the vertical web of the first drawer slide is punched toward the second drawer slide.
[0014] In an alternative embodiment, the lock between the second drawer slide and the first drawer slide has a lever biased toward the first drawer slide coupled to the second drawer slide, a tab coupled to the lever, and a hole in the first drawer slide. The tab moves into the hole in the first drawer slide as the second drawer slide is withdrawn from the first drawer slide, thereby preventing the second drawer slide being closed relative to the first drawer slide. In an additional embodiment, a c-shaped tab is formed in the web of the third drawer slide. The c-shaped tab is biased toward the second drawer slide. The c-shaped tab moves the lever and the tab away from the first drawer slide allowing the second drawer slide to be closed relative to the first drawer slide member.
[0015] In yet another embodiment, the telescopic drawer slide has a detent. The detent includes a hole in the lever of the second drawer slide and a raised bump on the c-shaped tab of the third drawer slide. When the third drawer slide is closed within the second drawer slide, the bump fits inside of the hole in the lever. The detent prevents movement of the third drawer slide relative to the second drawer slide until a predetermined amount of force is used to pull the third drawer slide from the second drawer slide. The detent causes the second drawer slide to be withdrawn from the first drawer slide prior to the withdrawing of the third drawer slide from the second drawer slide.
[0016] A telescopic drawer slide according to an embodiment of the present invention fits within a space between a drawer and a cabinet of about 0.375 inches wide by about 1 inch in height.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Other features and advantages of the preset invention will be set forth in part in the description which follows and in the accompanying drawings, wherein:
[0018] [0018]FIG. 1 is a cross-section view of a telescopic drawer slide according to an embodiment of the present invention;
[0019] [0019]FIG. 2 is a perspective view of a leading edge of an inner slide member according to an embodiment of the present invention;
[0020] [0020]FIG. 3 is a perspective view of a lock between the inner slide member and the intermediate slide member according to a first embodiment of the present invention;
[0021] [0021]FIGS. 4 a to 4 c top views of alterative spring formed stops according to a first embodiment of the present invention;
[0022] [0022]FIG. 5 is an elevational view taken from a side of a drawer slide showing the locking mechanism between the inner and intermediate slide members according to a second embodiment of the present invention;
[0023] [0023]FIG. 6 is a perspective view of the locking relationship between the inner and intermediate slide members according to a second embodiment of the present invention;
[0024] [0024]FIG. 7 is another perspective view of a lock between the intermediate slide member and the outer slide member according to an embodiment of the present invention;
[0025] [0025]FIG. 8 is a perspective view showing a lock between the intermediate slide member and the outer slide member according to an alternative embodiment of the present invention;
[0026] [0026]FIG. 9 is a cross-sectional view taken along line A-A of FIG. 9; and
[0027] [0027]FIG. 10 is a perspective view of a lock between the intermediate and outer slide members according to an alternative embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0028] A drawer slide incorporating the present invention is shown in FIG. 1. As shown in FIG. 1, an exemplary drawer slide has three separate slide members. The three slide members shown in FIG. 1 are an outer slide member 10 , an intermediate slide member 20 , and an inner slide member 30 . The three slide members are all slidably connected to one another. In alternative embodiments, the drawer slide has 4 or more slide members.
[0029] In the following description, it is assumed that the inner slide member is attached to a drawer and the outer slide member is attached to a cabinet. In practice, the outer slide member may be attached to a drawer and the inner slide member may be attached to a cabinet. Furthermore, the same drawer slide according to an embodiment of this invention, can be mounted on either side of the drawer without any modification.
[0030] The slide members fit within each other when the drawer is closed. In an embodiment, the drawer slide, in a closed position, fits inside of a space between the drawer and the cabinet having a size of approximately 0.375 inches wide by approximately 1 inch in height. In order to achieve this, the slide members increase in thickness from inner to intermediate to outer member. The inner slide member 30 nests within the intermediate slide member 20 which in turn nests within the outer slide member 10 . As shown in FIG. 1, the outer slide member 10 has an outer vertical web 12 and two outer slideways 14 . Each slideway has a horizontal portion 16 extending from the outer vertical web toward the drawer, and a vertical portion 18 that is oriented inward. The horizontal and vertical portions of the slideway in combination with a portion of the outer vertical web 12 encompass intermediate slideways of the intermediate slide member 20 .
[0031] The horizontal portions 16 of the outer slideways are slightly concave inward. As explained below, the bowed in horizontal portions 16 of the outer slide member are slid upon by the outside of intermediate slideways of the intermediate slide member 20 . The outside of the intermediate slideways of the intermediate slide member 20 contact only the top of the curve in the middle of the horizontal portions 16 of the outer slide member 10 . This reduces friction between the outer slide member 10 and the intermediate slide member 20 . Likewise, because the outer slideways are bowed inward, small pockets 19 are formed in slideway edges where the outer vertical web 12 meets the horizontal portion 16 and where the horizontal portion 16 meets the vertical portion 18 . The small pockets 19 run all along the length of the outer slide member 10 and function as reservoirs for lubricating material. The small pockets 19 also function as a depository for minute particles of materials produced during the wear of mating surfaces during use of the slide.
[0032] The outer vertical web 12 of the outer slide member 10 contains a number of holes that allow the outer slide member to be attached to either a cabinet or to a drawer. In an embodiment of the present invention, the outer slide member is attached to the cabinet using screws. In alternative embodiments, the outer slide member is attached using other attachment devices, such as nails, nuts, glue, and rivets. In yet another alternative embodiment of the present invention one or more brackets may be attached to the outer slide member, with the brackets themselves being attached to a cabinet or drawer.
[0033] The intermediate slide member 20 has intermediate slideways 25 . The intermediate slideways 25 are formed with a horizontal section attached to the intermediate vertical web 22 . Each slideway has a vertical section facing the opposite slideway. The horizontal section and vertical section, in combination with the intermediate vertical web, forms an enclosed space that encloses slider sections of the inner slide member 30 . In contrast to the horizontal portion of the slideways of the outer slide member 10 , the horizontal portions of the intermediate slideways 25 are not concave. The inside of the intermediate slideways 25 contain sharp corners. The outside corners of the intermediate slideways are curved to help form the pockets 19 on the inside of the outer slideways discussed above.
[0034] The intermediate slide member 20 also has an intermediate vertical web 22 . A portion of the intermediate vertical web 22 in the vertical center of the slide member is bent toward the drawer to form a hat section 24 . The hat section 24 has two angled portions leading from the intermediate vertical web to a vertical portion that is positioned closer to the drawer than the intermediate vertical web. The hat section is designed to fit over the screws or other means used to attach the outer slide member to a cabinet or drawer. Additionally, the hat section adds strength and stability to the intermediate slide member. In one embodiment, the hat section is recessed inward enough to clear the heads of number 8 screws or equivalent screw heads.
[0035] The inner slide member 30 has slider sections 31 that slide inside of the intermediate slideways of the intermediate slide member. The slider sections 31 are made of a vertical piece that has been bent 180 degree back upon itself, forming an edge 32 which slides on the inside of the intermediate slideway 25 . The edge 32 provides for point contact between the inner slide member 30 and the intermediate slide member 20 , reducing friction and the force necessary to extend and retract the inner slide member.
[0036] The inner slide member also has an inner hat section 33 . The inner hat section 33 has angled sides 34 leading to a vertical portion 35 . In an embodiment of the present invention, the vertical portion 35 of the inner slide member contains holes for attachment to either a cabinet or a drawer. In one embodiment, the inner slide member is attached using screws. In alternative embodiments, the inner slide member may be attached using other attachment devices, such as nails, nuts, glue, and rivets. The hat section 33 of the inner slide member is raised far enough away from the hat portion of the intermediate slide member to allow clearance of a number 8 screws or equivalent screw head. The hat section 33 of the inner slide member 30 is raised far enough away from the hat portion of the intermediate slide member to prevent contact between the hat sections of the intermediate and inner slide members.
[0037] The inner slide member has two ends. A first end is facing out from a closed position and forms one end point of the slide as it is opened. The first end of the inner slide member has a tab across the hat section. The tab functions as a stop because the tab is hit by the intermediate slide member when the inner slide member is fully closed.
[0038] A second end of the inner slide member is opposite to the first end. The inner slide member is removable from the intermediate slide member. After removal from the intermediate slide member, the second end of the inner slide member must be oriented to the intermediate slide member for reinsertion. As shown in FIG. 2, the second end of the inner slide member is tapered, and therefore the ends of the sliders are angled back into the inner slide member. The tapered second end of the inner slide member allows the slide member to align with an end of the intermediate slide member. The second end of the inner slide member is also chamfered to further assist in alignment between the inner slide member and the intermediate slide member.
[0039] The tapered second end is provided for in the preformed shape of the inner slide member. The taper eliminates the need to remove burrs caused by shearing the inner slide member. This is advantageous because the presence of burrs may lead to premature failure of the surface, thus increasing interference and later increasing the force required to move the inner slide member during drawer slide use.
[0040] The inner, intermediate, and outer slide members slide in relation to one another. In order to keep a drawer sliding evenly on both sides, the drawer slides are designed to open and close the same way in a process which may be termed sequencing. By using locks and detents, further described below, the intermediate slide member 20 is pulled out of the outer slide member 10 first. Once the intermediate slide member 20 has been fully extended from the outer slide member 10 , the inner slide member 30 is released from the intermediate slide member 20 . Likewise, when closing a drawer slide, the inner slide member 30 is closed back inside of the intermediate slide member 20 . After the inner slide member 30 is completely inside of the intermediate slide member 20 , the intermediate slide member 20 is released to close into the outer slide member 10 .
[0041] In an alternative embodiment of the present invention, the inner slide member 30 opens from the intermediate slide member 20 before the intermediate slide member opens from the outer slide member 10 . Likewise, in the alternative embodiment, the intermediate slide member 20 closes inside of the outer slide member 10 before the inner slide member 30 closes inside of the intermediate slide member 20 .
[0042] In a first embodiment of the present invention, shown in FIG. 3, a lock is placed between the inner slide member 30 and the intermediate slide member 20 so that someone cannot pull the inner slide member 30 out of the intermediate slide member 20 beyond a preselected point. In the first embodiment, the inner slide member has a spring formed stop 26 located approximately one third of the way from the second end of the inner slide member on the inside of the inner slide member. The spring formed stop has a first portion that extends toward the intermediate slide member 20 from the inner slide member. At the end of the first portion is a rectangular portion 28 . The rectangular portion 28 is biased toward to the intermediate slide member by the first portion.
[0043] The intermediate slide member has a hole 27 to catch the rectangular section of the spring formed stop. The intermediate slide member has two ends. A first end of the intermediate slide member is oriented to the second end of the inner slide member when the inner slide member is extended. In an embodiment of the present invention, the hole 27 that catches the spring formed stop is positioned near the first end of the intermediate slide member. A second end of the intermediate slide member is oriented opposite to the first end of the intermediate slide member.
[0044] As the spring formed stop passes over the hole 27 in the intermediate slide member, the spring formed stop springs into the hole. Once in the hole, the spring formed stop impacts the edge of the hole in the intermediate slide member and prevents the inner slide member from being further extended from the intermediate slide member. This prevents accidental removal of the inner slide member of the intermediate slide member and thus, the accidental removal of the drawer from the cabinet. The removal of the inner slide member from the intermediate slide member, and hence the removal of the drawer from the cabinet is possible, by manually pressing the spring formed stop 26 out of the hole 27 in the intermediate slide member.
[0045] The placement of the spring formed stop 26 also creates staging, because once the inner slide member is totally extended, and the spring formed stop 26 is in the hole 27 of the intermediate slide member, all of a drawer opening force pulls the intermediate slide member 20 out of the outer slide member 10 .
[0046] In an additional embodiment of the present invention, the hole 27 in the intermediate slide member and the spring formed stop 26 are designed so that the spring formed stop does not catch the edge of the hole when the drawer is being closed. Therefore, the spring formed stop does not prevent the inner slide member from closing inside of the intermediate slide member.
[0047] As shown in FIGS. 4 a to 4 c, the spring formed stop 27 is attached to the inner slide member. In an embodiment, shown in FIG. 4 a, the rectangular portion 28 is formed as a rectangular stamping. In an alternative embodiment, shown in FIGS. 4 b and 4 c, the rectangular portion is a three dimensional rectangular structure attached to the first portion of the spring formed stop. The spring formed stop 27 may be attached using one or more fasteners, such as rivets, that go through one or more holes 29 in the spring formed stop and one or more holes in the inner slide member. Alternatively, the spring formed stop 27 may be attached by staking, where a portion of the inner slide member is stamped to fit around the spring formed stop.
[0048] In a second embodiment of the present invention a different type of lock is used between the inner and intermediate slide members. In this alternative embodiment, shown in FIG. 5, the lock, once initiated, prevents the inner slide member from being opened further or closed in relation to the intermediate slide member.
[0049] In the second embodiment of the present invention, the inner slide member has a spring biased lever 37 positioned inside of the inner hat section. The lever 37 has an angled portion 38 that is oriented outward. The lever also has a square cut out 39 along an edge adjacent to the intermediate slide member. A spring biases the lever 37 so that the square cut out 39 is always being pressed outwards toward the intermediate slide member 20 . In an embodiment of the present invention, the lever 37 is attached to the inner slide member 30 by means of a rivet. In alternative embodiments, the lever may be attached using nuts and bolts, screws, or other means of attachment, that allow the lever to rotate around the point of attachment.
[0050] Also in the second embodiment of the present invention, the intermediate slide member 20 has a segment of the angled portion of the hat section 24 stamped inward. The inward stamped portion extends into the hat section 33 of the inner slide member 30 forming a protrusion 40 . As the inner slide member 30 and the attached spring biased lever 37 passes the protrusion 40 of the intermediate slide member, the angled portion 38 of the lever is pressed downward due to the angle of impact. The force necessary to further move the inner slide member and the lever may be manipulated by changing the strength of the spring biasing the lever. The lever continues to be pushed against the force of the spring until the square cut out 39 of the lever is positioned over the protrusion 40 of the intermediate slide member 20 . At this point, the force of the spring forces the lever down over the protrusion, and the lever is locked in place. In order to release the inner slide member from the lock, the lever must be moved over the protrusion. In an embodiment of the present invention, a user simply pushes the lever against the spring force, thus moving the lever over the protrusion and allowing the inner slide member to be either opened or closed.
[0051] In an alternative embodiment, shown in FIG. 6, attached to the inner slide member is a release lever 41 that releases the lock. The release lever 41 is attached to the inner slide member 30 with shoulder rivets 42 . The use of shoulder rivets allows the release lever to be translated, along the length of the inner slide member. Pushing the release lever 41 , particularly along a tab 43 at a forward end of the release lever 41 , causes an end 44 of the release lever 41 to press against the angled edge 38 of the lever 37 . This results in a rotation of the lever 37 such that the square surface 39 of the lever 37 is rotated over the protrusion 40 , thus releasing the lock.
[0052] A locking mechanism also exists between the intermediate slide member and the outer slide member. The locking mechanism prevents the intermediate slide member from closing inside of the outer slide member until the inner slide member is closed inside of the intermediate slide member. As shown in FIG. 7, in an embodiment of the present invention, a tab 46 is attached to the second end of the intermediate slide. The tab is “T” shaped. The tab 46 is attached using a rivet 48 . In alternative embodiments, the tab 46 may be attached using other attachments means that allow the tab to rotate around the point of attachment, such as a nut and bolt.
[0053] The “T” shape provides a rotational limit for the tab, because the top of the “T” impacts the slideways of the outer slide member. The tab is moved by the force of its own weight depending on the orientation of the slide. This allows the slide to be used on either the left or right side of a drawer, and allows the slide to be affixed with either the outer slide member or the inner slide member attached to a drawer.
[0054] The tab 46 has a first area 49 adjacent to the attachment that flares to a larger width toward the second end of the intermediate slide member. The tab has a second area 50 that extends outward from the end of the intermediate slide member. The second area forms the top of a “T” shape and has edges 51 that are folded down to impact an emboss 52 located on the outer slide member. When in a neutral position the second area extends out from the intermediate slide member in parallel to the intermediate slide member. When biased by the weight of the tab 46 , the second area slopes downward on an angle and locks in the emboss. When locked in the emboss 52 , the angle of the second area of the tab is such that the tab blocks the path of the inner slide member. The inner slide member impacts the angled second area and the angle of impact forces the tab back to a neutral position, thus enabling the tab to clear the emboss 52 .
[0055] The tab 40 also has reliefs 60 between the first and second area. The reliefs 60 are small cutouts in the tab. The reliefs 60 prevent distortion of the second end of the intermediate slide member which impacts the tab when the tab is engaged in the emboss 52 on the outer slide member 10 .
[0056] The emboss 52 on the outer slide member 10 functions as a stop for the tab 46 on the intermediate slide member 20 . The emboss 52 is arrow shaped with the arrow head pointing toward the closed position. Thus, the emboss 52 has an angled portion 54 , a horizontal portion 56 and a vertical edge 57 from the horizontal portion to a narrow stem 58 .
[0057] As the intermediate slide member is extended, the angled head of the emboss 52 allows the tab 46 to pass over the angled portion 54 and onto the horizontal portion 56 despite the weight of the tab. Once past the horizontal portion 56 , the tab reaches the vertical edge 57 and narrow stem and the weight of the tab forces the tab down the vertical edge 57 against the narrow stem 58 . When a closing force is applied to the intermediate slide member, the downward angled second area of the tab impacts the vertical edge 57 of the emboss and is immobile until the inner slide member acts on the downward angled second area of the tab to return the tab to the neutral position. The force of the inner slide member counteracts the weight of the tab and pushes the tab upward so that the tab can then clear the emboss 52 . Once clear of the emboss 52 , the intermediate slide member 20 may close inside of the outer slide member.
[0058] In an additional embodiment of the present invention, the horizontal edge 56 transitions into an edge more than 90 degree inward. The additional angle beyond 90 degrees prevents the tab from disengaging from the emboss due to vibration, bounce or excessive force.
[0059] A lock is present to prevent the intermediate slide member 20 from coming completely out of the outer slide member 10 . Near the second end of the intermediate slide member, a portion of the angled sides of the hat section of the intermediate slide section are punched downward toward the outer slide member 10 forming a stop.
[0060] The outer slide member has a portion in the outer vertical web 12 punched upward toward the intermediate slide member 20 that prevents the downward punched area of the intermediate slide member from moving past. In an embodiment, the raised portion of the vertical web of the outer slide member has a hole where two strips of metal are oriented toward the intermediate slide member. The two strips of metal impact the downward punched areas of the intermediate slide member. This prevents the accidental removal of the intermediate slide member from the outer slide member.
[0061] In an alternative embodiment of the present invention, a different lock is used to force the inner slide member 30 to close inside of the intermediate slide member 20 , before the intermediate slide member 20 closes inside of the outer slide member 10 . As shown in FIGS. 8, 9, and 10 , the vertical portion 38 inner slide member, at a point near the second end, has a “c-shaped” cutout section 70 . Within the “c-shaped” cutout section 70 is a tab 72 . The tab 72 is bent toward the intermediate slide member 20 . On the tab 72 is a button 74 .
[0062] Attached to the intermediate slide member 20 near the second end of the intermediate slide member 20 is a receiver 80 . The receiver 80 is attached to the intermediate slide member using a rivet 82 . In an additional embodiment, the receiver 80 may be attached using nuts and bolts, screws, or other means of attachment that allow the receiver to flex inward and outward in relation to the intermediate slide member 20 .
[0063] The receiver 80 extends from the point of attachment toward the first end of the intermediate slide member. The receiver has a head 84 with a hole 86 in it. The head 84 also has flanges 88 which extend through a hole in the intermediate slide member to the outer vertical web 12 of the outer slide member 10 . The flanges are straight on the side closer to the second end of the intermediate slide member, and angled on the other side. The receiver has a springlike aspect and keeps the flanges in contact with the outer slide member. At the end of the receiver closest to the first end of the intermediate slide member, the receiver 80 has a lip 90 upturned toward the inner slide member. The upturned lip helps to guide the “c-shaped” tab 82 into the receiver.
[0064] The outer slide member has a hole punched through the outer vertical web 12 . When the intermediate slide member 20 and the attached receiver 80 pass over the hole in the outer vertical web, the flanges lodge themselves in the hole in the outer vertical web. As the intermediate slide member 20 is pushed back into the outer slide member 10 the flanges 88 prevent the intermediate slide member from moving.
[0065] The receiver catches the tab 74 on the inner slide member 30 , as the inner slide member 30 reaches a closed position within the intermediate slide member 20 . The inner slide member 30 is forced to slide into the intermediate slide member first because the flanges 88 lock the intermediate slide member in place. Once the inner slide member reaches the closed position of the intermediate slide member, the “c-shaped” tab 72 enters the receiver 80 and pulls the receiver 80 toward the inner slide member 30 . The pulling of the receiver 80 moves the flanges 88 out of the hole in the outer vertical web 12 and allows the intermediate slide member to be closed into the outer slide member.
[0066] Once the “c-shaped” tab 72 of the inner slide member 30 enters the receiver 80 , the button 74 on the “c-shaped tab” 72 engages in the hole 86 of the receiver 80 forming a detent. A significant amount of force is required to move the button 74 out of the hole 86 . This allows staging in reverse, because the drawer opening force will first pull the intermediate slide member 20 out of the outer slide member 10 . Once the intermediate slide member 20 is pulled out of the outer slide member 10 , then a drawer opening force disengages the button 74 from the hole 86 of the receiver 80 . Once the button 74 disengages from the hole 86 , the inner slide member 30 may be extended from the intermediate slide member 20 .
[0067] In order to prevent the intermediate slide member 20 from being pulled all the way out of the outer slide member an additional lock is provided. At a point between the receiver 80 and the first end of the intermediate slide member, the hat section of the intermediate slide member is punched toward the outer slide member 10 to create two tabs 92 extending toward the outer slide member. A portion of the outer vertical web 12 is punched in to create tabs 94 that extend up into the hat section of the intermediate slide member 20 . The tabs 94 of the outer slide member impact the tabs 92 of the intermediate slide member 20 as the intermediate slide member is pulled out of the outer slide member. The tabs prevent the intermediate slide member from being removed from the outer slide member.
[0068] Each of the three slide members contain bends in them to maximize the stiffness and stability of each slide member across its length. The clearance between each of the slide members is designed to be a minimum so that the material thickness of each slide can be maximized for strength, rigidity and wear. The small clearance between each slide member prevents play and interference between slide members.
[0069] In an embodiment of the present invention, each of the slide members is formed through roll forming. Roll forming allows the slides to be inexpensively, and quickly mass produced. Roll forming also provides consistency in the characteristics of the drawer slides.
[0070] Although this invention has been described in certain specific embodiments, many additional modifications and variations will be apparent to those skilled in the art. It is therefore to be understood that this invention may be practiced otherwise and as specifically described. Thus, the present embodiments of the invention should be considered in all aspects as illustrative and not restrictive.
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A telescopic drawer slide including first, second and third drawer slides, each having a longitudinal length with a web and arcuate arms along the longitudinal margins of the web, the second drawer slide being nested within the arcuate arms of the first drawer slide, and the third drawer slide being nested within the arcuate arms of the second drawer slide. There is a lock between the second drawer slide and the first drawer slide, the lock having a biased tab rotatably coupled to the second drawer slide and an emboss on the first drawer slide. The tab moves into a portion of the emboss upon movement over the emboss, thereby preventing the second drawer slide from closing relative to the third drawer slide.
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REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of United Kingdom Application No. 1521893.6, filed Dec. 11, 2015, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a handheld product comprising a motor.
BACKGROUND OF THE INVENTION
[0003] When developing a handheld product, it is important to consider a number of factors that will affect the end-user. For example, the size and weight of the product must be kept down in order that a user is able to handle the product easily, and that the product does not cause discomfort to the user during use. Another important consideration is that of noise. It is preferable that a handheld product does not produce a level of noise that is unpleasant and/or uncomfortable during use. What is more, excessive noise could potentially be damaging to a user's hearing if the product is used regularly over a long period of time. It is often the case that additional soundproofing, for example foam, is included in a product in order to maintain an acceptable level of noise generated by the product. Alternatively, the motor can be run at a lower power to reduce the level of noise that it generates. Of course, neither of these solutions are particularly desirable. Additional components or materials such as foam will increase the cost of the product, and running the motor at a lower power will negatively affect the performance of the product.
[0004] In handheld products which contain motors, it is often the motor that contributes the most towards the weight of the overall product and also towards the noise of the product during use. In smaller, handheld products, it is usual for many components of the motor to be formed of plastics which are more lightweight than other alternative materials.
SUMMARY OF THE INVENTION
[0005] Aspects of this invention provide a handheld product comprising a motor for generating an airflow through the product, the motor comprising: a frame for supporting a rotor assembly and a stator assembly, the frame comprising an inner wall and an outer wall and a plurality of diffuser vanes extending between the inner wall and outer wall; a rotor assembly comprising a shaft, a magnet, a bearing assembly and an impeller; and a stator assembly comprising a bobbin, a stator core and a winding wound round the bobbin; the frame being formed of zinc and the impeller being formed of aluminium.
[0006] As a result, the frame, being formed of zinc which is an acoustically dull material, is able to absorb some of the frequencies generated by the motor during use, and in particular the acoustic frequencies. This reduces the level of noise from the motor, and in turn reduces the overall noise generated by the handheld product during use. What is more, by forming the impeller from aluminium, which is an extremely light and strong material, this helps to counteract the additional weight included into the motor due to the use of zinc to form the frame. Therefore there is a synergistic effect in the use of zinc in the frame and aluminium in the impeller. The combination of the aluminium impeller and the zinc frame affords the motor improved acoustic characteristics, but without compromising the overall weight of the motor. Therefore, a handheld product can be achieved that is quieter during use, but without a significant increase to the weight of the overall product.
[0007] The magnet and the impeller may be fixed to the shaft either side of the bearing assembly. This allows the rotor assembly to be evenly balanced, and reduces the forces acting on the bearing assembly during use. This can extend the life of the motor.
[0008] The impeller may be an axial impeller. The frame may be formed from zinc by one or a combination of die-casting and machining. The outer wall of the frame may be substantially cylindrical and may have a substantially uniform internal diameter.
[0009] The bearing assembly may be mounted within the inner wall of the frame. This allows the inner wall to act as a protective sleeve for the bearing assembly. As such, no additional sleeve is required, and so the cost, weight and size of the motor can be reduced.
[0010] The impeller may be formed of machined aluminium, and may comprise a plurality of blades positioned radially around an inner hub. The inner hub of the impeller may comprises a recess. Accordingly, the weight of the impeller can be further reduced, and as such further counteracting the additional weight caused by the zinc frame.
[0011] The impeller may comprise 13 blades. As such, the blades of the impeller will generate a frequency during use that is high enough to be outside the typical hearing range of a human. Accordingly, the acoustic impact of the motor, and therefore the overall product, can be reduced.
[0012] During use, the rotor may spin at a speed of between 75 and 110 krpm to generate airflow through the product. This generates the desired level of air flow through the product, but exerts large forces on the impeller. However, being made of aluminium, the impeller is capable of withstanding these large forces.
[0013] The handheld product may be a hair care appliance, and may be one of a hair dryer, or a hot styling brush.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order that the present invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the following accompanying drawings, in which:
[0015] FIG. 1 is a handheld product in the form of a hair dryer;
[0016] FIG. 2 is a cross section through the hair dryer of FIG. 1 ;
[0017] FIG. 3 is an exploded perspective view of a motor;
[0018] FIG. 4 shows a cross section through a frame of the motor of FIG. 3 ;
[0019] FIG. 5 shows a cross section through a rotor assembly of the motor of FIG. 3 ;
[0020] FIG. 6 is an axial impeller; and
[0021] FIG. 7 shows a cross section through a partly assembled motor such as that shown in FIG. 3 .
DETAILED DESCRIPTION OF THE INVENTION
[0022] FIGS. 1 and 2 show a handheld product, represented by hair dryer 1 . FIG. 2 is a schematic illustration of a cross section through the hair dryer 1 . The hair dryer 1 has a body 2 through which air is expelled, and a handle 3 attached to the body 2 by which a user can hold the hair dryer 1 as shown in FIG. 2 . The handle 3 comprises an air intake 4 at an end of the handle 3 opposite the body 2 . A motor 5 is located within the handle 3 such that it is positioned next to, or at least close to, the air intake 4 . A filter or other filtering means (not shown) may be provided at the air intake 4 , or between the air intake 4 and the motor 5 , to prevent foreign objects which may be entrained in the airflow, such as hair or dust, from entering the motor 5 .
[0023] During use, the motor 5 generates an airflow through the hair dryer 1 . The motor 5 draws air into the handle 3 through the air intake 4 . Air then passes through the motor 5 and from the handle 3 into the body 2 where is directed towards an air outlet 6 . A heater (not shown), for example in the form of one or more heating elements, may be provided in the hair dryer 1 to heat the air prior to it being expelled from the air outlet 6 .
[0024] A hair dryer 1 is shown as an example in FIGS. 1 and 2 , however the motor 5 could be used in other handheld products that require the generation of an airflow. For example, the motor 5 could be included in a different hair care appliance: for instance a hot styling brush.
[0025] FIG. 3 is an exploded perspective view of the motor 5 . The motor 5 comprises a frame 10 , a rotor assembly 20 and a stator assembly 40 . A cross section through the frame 10 is shown in FIG. 4 . The frame 10 comprises an inner wall 11 and an outer wall 12 . A number of diffuser vanes 13 extend between the inner wall 11 and the outer wall 12 . The frame 10 is formed of zinc and can be formed, for example, by machining or die-casting, or a combination of both machining and die-casting. Zinc is an acoustically dull material and so the frame 10 is able to effectively absorb acoustic frequencies generated by the motor 5 during use. The zinc frame 10 therefore acts to reduce the overall level of noise generated by the product 1 during use.
[0026] The rotor assembly 20 comprises a shaft 21 , a magnet 22 , a bearing assembly 23 and an impeller 24 . A cross-section through the rotor assembly 20 is shown in FIG. 5 . The magnet 22 , bearing assembly 23 and impeller 24 are all fixed directly to the shaft 21 by one or a combination of an interference fit and adhesive. The magnet 22 is a bonded permanent magnet of the sort typically used in permanent magnet brushless motors. In the example shown, the magnet 22 is a four-pole permanent magnet. The bearing assembly 23 comprises a pair of bearings 25 a , 25 b and a spring 26 separating the bearings 25 a , 25 b . The spring 26 acts to pre-load each of the outer races of the bearings 25 a , 25 b to reduce wear of the bearings during use. Once the rotor assembly 20 is assembled into the frame 10 , the inner wall 11 of the frame 10 acts as a protective sleeve around the bearing assembly 23 . The outer races of the bearings 25 are fixed to the inside circumference of the inner wall 11 by adhesive.
[0027] The impeller 24 shown in the Figures is an axial impeller with a plurality of blades 27 spaced circumferentially around, and extending radially out from, a central hub 28 . During use, as each blade 27 spins, it creates sound waves at a specific frequency. It is therefore possible to design the impeller in such a way as to reduce its acoustic impact. The impeller 24 shown in FIGS. 3 and 5 comprises eleven blades. However, the number of blades 27 may differ according to the acoustic requirements of the motor 5 and/or handheld product. For example, an impeller 30 with thirteen blades 27 is shown in FIG. 6 . During use, due to the higher number of smaller blades 27 , the impeller 30 of FIG. 6 may generate an acoustic tone that has a higher frequency than the impeller 24 of FIG. 3 that has only eleven blades 27 . At the expected operating speeds for the motor 5 , the frequency of the tone generated by an impeller 30 with thirteen blades 27 is high enough so as to be outside the typical hearing range of a human. This reduces the acoustic impact of the motor 5 and goes even further to reduce the overall noise generated by the product, i.e. the hair dryer 1 , during use.
[0028] The impeller 24 , 30 is formed by machining aluminium. Aluminium is a very light material and therefore by using it to form the impeller 24 , 30 this helps to counteract some of the additional weight included in the motor 5 by using zinc to create the frame 10 . When used in a handheld product such as the hair dryer 1 of FIGS. 1 and 2 , or another hair care product, the motor 5 will typically be run at rotational speeds of around 75 to 110 krpm. The magnitude of the forces acting on the impeller 24 , 30 at these high speeds are very great. Thankfully, despite being light, aluminium is also very strong and so the impeller 24 , 30 is capable of withstanding the large forces subjected to it when it rotates at high speed.
[0029] FIG. 5 shows that the hub 28 of the impeller 24 comprises a recess 29 in the downstream side of the hub. By having a recess 29 , this further decreases the weight of the impeller 24 , 30 , which counteracts even more of the weight added by using zinc to form the frame 10 . In addition, the recess 29 is annular and provides a cavity into which an axially extending portion or protrusion of the inner wall of the frame can extend. This creates a labyrinth seal inside the hub 28 of the impeller 24 which prevents foreign objects, such as hair and dust, from entering into the bearing assembly 23 which could damage the rotor assembly and significantly reduce the lifetime of the motor. The labyrinth seal can be seen in FIG. 7 which shows a cross section through the assembled frame 10 and rotor assembly 20 . The labyrinth seal is highlighted at area S. FIG. 7 shows how the inner wall 11 of the frame 10 acts as a protective sleeve around the bearing assembly 23 , as previously described.
[0030] Whilst particular embodiments have thus far been described, it will be understood that various modifications may be made without departing from the scope of the invention as defined by the claims.
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A handheld device comprising a motor for generating an airflow through the device, the motor including: a frame for supporting a rotor assembly and a stator assembly, the frame including an inner wall and an outer wall and a plurality of diffuser vanes extending between the inner wall and outer wall; a rotor assembly including a shaft, a magnet, a bearing assembly and an impeller; and a stator assembly including a bobbin, a stator core and a winding wound around the bobbin; the frame being formed of zinc and the impeller being formed of aluminium.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an assembly of at least one plate-shaped data carrier and a box-shaped storage device therefor according to the preamble of claim 1. Such an assembly is known from British patent application 2 154 550.
2. Description of the Related Art
In this known assembly the storage device comprises covers joined to a spine by parallel hinges, a holder being fixed to said spine. The hinges permit initial opening of one of the covers relative to said spine about a hinge, after which the spine moves with the cover about the other hinge, so that the holder is raised away from the other cover, thus presenting the contents thereof. The covers and the spine are defined by a single sheet. A pair of parallel grooves is formed, by scoring, in one face of the sheet to define said hinges. The spine is defined between said hinges.
Each cover is reinforced by a rectangular frame molded onto the sheet, each frame extending along the edges of each cover, except for the edge defined by one of the hinges. The holder is molded onto the spine of the sheet and is provided with receiving means, receiving the compact disc and gripping this lightly along a circumferential edge thereof. Preprints may be provided on the outer face of the sheet before molding the frames and the holder onto the sheet.
In this known storage device the receiving means are provided by a pocket-like holder having two sidewalls enclosing a groove there between, which extends over an enclosed angle of more than 180°. The said walls are interconnected by side walls on either side, defining at each free end of said groove clamping projections. When the compact disc is inserted into said receiving means the clamping projections extend above the centerline of the compact disc, such that the compact disc is forced into said groove.
This known storage device has the disadvantage that the said sidewalls have to extend on both sides of the circumferential edge of the compact disc, in order to position the clamping means in said position. Thus, the storage device has to be substantially wider than the compact disc. Furthermore, in this known storage device the compact disc is only clamped near said clamping projections, thus providing room for the compact disc to move inside said groove, whereby the stored compact disc can be damaged. Moreover, such storage device necessitates relatively large amounts of plastic and relatively long production times, which render such storage device relatively costly. Moreover, positioning a compact disc into this known storage device as well as removing such is rather difficult, due to said clamping directions by said clamping means.
A further assembly of at least one plate-shaped data carrier and a box-shaped storage device therefore is known from European patent application 0 420 350.
In the storage device in the known assembly, the first closing part is box-shaped, provided with a bottom and raised walls. The second closing part is cover-shaped and can be closingly fitted against the first closing part. The first closing part is provided, adjacent a central area thereof, with resilient fingers arranged in circular form and extending from the bottom, which fingers can engage through a central opening of the data carrier to retain the data carrier within the walls in a position approximately parallel to the bottom face mentioned. Hence, when the cover-shaped second closing part is being closed over the first closing part, the data carrier is stored within the storage device so as to be protected against influences from outside. After the first closing part has been swivelled aside, the data carrier can be removed from the known storage device by engaging the data carrier at the circumferential edge thereof, pressing the resilient fingers at least partially away in the direction of the center of the circle formed thereby and pulling the data carrier away from the resilient fingers in a direction at right angles to the bottom face. When the data carrier is being positioned, it is simply pressed with its central opening over the resilient fingers, which, accordingly, are temporarily pressed away to allow the data carrier to pass.
This known storage device has a number of drawbacks. For instance, in the known storage device, only data carriers can be stored that are provided with a central opening. Moreover, it is not easy to remove from the resilient fingers such a data carrier disposed thereon. There is little space for engaging the circumferential edge and, moreover, the data carrier should be gripped with one hand, while the resilient fingers are pressed away with the other hand, so that always two hands are required for removing the data carrier. This moreover involves a great chance that the user touches the data-carrying part of the data-carrying part of the data carrier, so that damages may be caused thereto. Further, the resilient fingers should be on the one hand sufficiently flexible to allow the data carrier to pass, and on the other sufficiently stiff to be able to retain the data carrier. Because of this combination of requirements, the freedom of choice of material for the relevant first closing part wherein the resilient fingers are integrally formed is considerably limited to relatively costly materials. Further, the resilient fingers are not sufficiently durable to enable a long and repeated use thereof. When the fingers break off, the data carrier can no longer be properly secured, which renders the storage device unusable.
BRIEF SUMMARY OF THE INVENTION
The object of the invention is to provide an assembly of the type described in the preamble, wherein the drawbacks mentioned are avoided, while the advantages thereof are retained. To that end, an assembly according to the invention is characterized by the features of claim 1.
Because in an assembly according to the invention, the clamping projections engage a plate-shaped data carrier along a portion of the circumferential edge thereof, a storage device within the assembly can be used for storing plate-shaped data carriers, independently of the presence of a central opening. Because the clamping projections engage the data carrier on either side, for example, against the flat side faces thereof, the data carrier can be properly clamped and yet readily removed, without the clamping projections having to undergo a substantial deformation for that purpose. When a data carrier is being positioned, the clamping projections are pressed apart only slightly and thus provide the clamping of the data carrier. When the data carrier is being removed, the resilient clamping projections slide over the side faces of the data carrier until it is released therefrom, whereupon the clamping projections rebound into their original position.
Since the groove encloses an angle of less than 180°, the storage device can have a width comparable to the diameter of the data carrier to be stored. Furthermore, relatively little material is necessary for producing such storage device, which makes it possible to produce such storage device relatively quick and easy and thus economical. Furthermore, a data carrier can be easily introduced into and withdrawn from the groove, due to the open construction of the groove in the direction of withdrawal. Thus, the data carrier can readily be positioned and removed with one hand.
A further advantage of the clamping direction of the clamping projections is that they can be of a flat design in a direction at right angles to the deformation direction, while in the known device, the clamping projections should be slightly bent in a direction at right angles to the deformation direction. Consequently, the resilient clamping projections in a storage device according to the invention can be of a relatively wide design, without this causing the action thereof, in particular the force required for the deformation, to increase unacceptably, so that the resilient clamping projections in a storage device according to the invention can be of a stronger and more durable design. In addition, engagement of the data carrier along a circumferential edge offers the advantage that a larger surface area is available for gripping by means of the clamping projections and, moreover, that the clamping projections engage the data carrier from two sides in directions towards each other, so that in order that the data carrier can be received in a sufficiently fixed manner all the same, relatively little clamping force per clamping projection or at least per surface is required. For this reason, too, the deformations in the clamping projections can be kept relatively limited, which considerably increases the durability of the assembly.
In an advantageous embodiment, an assembly according to the invention is characterized by the features of claim 2.
By engaging the data carrier at a portion thereof that does not carry any data, the data carrier is readily prevented from being damaged in such a manner that data are lost, also when the clamping projections are slid across the surfaces of the data carrier.
In a further advantageous embodiment, an assembly according to the invention is characterized by the features of claim 3.
The arrangement of a series of clamping projections along each longitudinal side of the groove has the advantage that the data carrier is engaged at a number of locations, while, moreover, the clamping projections are not unpleasantly stiff, because, viewed in the direction of the groove, parallel to the plane of a data carrier received therein, they are relatively short relative to the length of the groove. By positioning the clamping projections opposite each other to form pairs, the advantage is obtained that the data carrier is not deformed by the clamping projections, because the pressure force of each clamping projection is compensated by the pressure force of the opposite clamping projection.
In a preferred embodiment, an assembly according to the invention is characterized by the features of claim 5.
Engagement of the data carrier at the two flat sides thereof is particularly favorable for the positioning and/or removal thereof, in particular when positions of the data carrier at which it can be engaged carry no data, at least not in a manner in which it can be damaged. Thus, the force required for positioning or removing can be supplied more simply. An additional advantage of such embodiment is that the data carrier is visible from two sides, so that information provided on either side thereof remains visible. Moreover, when data carriers used in the known assembly are used within an assembly according to the invention, this offers the advantage that for instance a finger of a user or a pick-up means can engage through the central opening for picking up or positioning the data carrier. Thus, contact between the user and at least the or each data-carrying part of the data carrier can readily be prevented, while the data carrier remains nevertheless readily manipulable.
During the use of an assembly according to the invention, in particular according to this embodiment, a data carrier can for instance directly be brought from the storage device into a reading device and vice versa, for instance in an automized device. Also during the production of the assemblies, the fitting of the or each data carrier in the storage device can thus be provided in a simple and economical manner.
A storage device according to the invention is particularly suitable for storing circular discs, such as compact discs (CD, CD-i, CD-ROM), video discs, long-playing records and singles, and the like.
In a particularly advantageous embodiment, an assembly according to the invention is characterized by the features of claim 6, in particular of claim 7.
By disposing the receiving means in an intermediate part which is pivotally connected to one of the closing parts, a simple construction of the storage device is obtained, wherein different intermediate parts can be arranged side by side for receiving a series of data carriers. In this connection, it is particularly advantageous when the two closing parts are pivotally connected to the intermediate part or, if several intermediate parts are included, at least to the adjacent intermediate parts. This enables the closing parts on either side of an intermediate part to be pivoted aside, so that the data carrier is free on either side. This is advantageous in particular if the two closing parts can be pivoted approximately in the same plane, because a storage device according to the invention can then be placed with the closing parts on a flat face, while the or each data carrier, received in an intermediate part, can then extend in a plane which includes an angle with the flat face on which the storage device is disposed. The data carrier is then optimally accessible to a user or to a device for the positioning or removal thereof. Moreover, a data carrier can thus be presented in an attractive manner by means of the storage device.
The or each intermediate part can be detachable connected to one or both closing parts and any other intermediate parts, which renders the intermediate part usable as receiving means for a data carrier during manipulation thereof.
In a further preferred embodiment, however, an assembly according to the invention is characterized by the features of claim 9.
A storage device in such an assembly offers the advantage that it can be manufactured in one pass. Because such a storage device need not be built up from different loose parts, the manufacturing process thereof can be carried out in a simple and economical manner, also in a completely automized manner. Moreover, during use, this does not involve the danger that coupling means such as pivot pins and the like, break off, as a consequence of which the storage device would lose its function. A further advantage of such storage device is that it entirely consists of one material, so that no different parts need to be separated before recycling of the material is possible.
An assembly according to the invention is further characterized in an advantageous embodiment by the features of claim 10.
A closure of a storage device by means of closing fingers engaging an opening in the closing part enables a particularly simple operation of the storage device and can moreover be provided in the storage device in a relatively simple manner.
An assembly according to the invention is further characterized in an advantageous embodiment by the features of claim 11.
A storage device in such an assembly offers the advantage that it can be manufactured in one pass. Because such a storage device need not be built up from different loose parts, the manufacturing process thereof can be carried out in a simple and economical manner, as well as in a completely automized manner. Moreover, during use, this does not involve the danger that coupling means such as pivot pins, hinges and the like, break off, as a consequence of which the storage device would lose its function. A further advantage of such storage device is that it entirely consists of one material, so that no different parts need to be separated before recycling of the material is possible. Furthermore, since a storage device according to the present invention is manufactured in one pass construction faults are avoided.
Furthermore the invention relates to a storage device having the features of a storage device in an assembly according to the present invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
To explain the invention, exemplary embodiments of an assembly will hereinafter be described, with reference to the accompanying drawings, wherein:
FIG. 1 is a top plan view of a storage device in open position;
FIG. 2 is a front view of a storage device according to FIG. 1;
FIG. 2A is an enlarged sectional view of a storage device taken on the line A--A in FIG. 3;
FIG. 3 is a sectional side elevation of a storage device according to FIG. 1, suitable for substantially circular data carriers;
FIG. 4 is an enlarged sectional view of a closure of a storage device;
FIG. 5 is front and top plan view of a storage device in an alternative embodiment, with data carriers included therein;
FIG. 6 is a sectional side elevation of a storage device according to FIG. 1, in an alternative embodiment, with data carriers included therein;
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a storage device 1 for a data carrier 2. A data carrier 2 to be stored can for instance be circular, such as compact discs (CD-i, CD-ROM; FIG. 3). The storage device 1 according to FIG. 1 is of a one-piece construction and for instance manufactured through injection molding from a relatively environmentally friendly, recyclable plastic such as polypropene.
The storage device 1 as shown in the Figures comprises a first closing part 3, an intermediate part 4 and a second closing part 5. The first closing part 3 and the second closing part 5 are connected to the intermediate part 4 via two integrated pivots 6 adjacent the bottom side, so that the two closing parts 3, 5 are at least pivotable through an angle of 90° relative to the intermediate part 4, so that they can be pivoted from the position shown in FIGS. 1-3 into a closed position shown in a broken lines in FIG. 2.
The first closing part 3 has substantially rectangular top face 7, comprises a substantially closed front edge 8 at the longitudinal edge thereof remote from the pivots 6, and comprises partially closed first sidewalls 9 at the two longitudinal edges adjoining that front edge. The second closing part 5 likewise has a rectangular top face 10 and comprises an upright second sidewall 11 at two opposite longitudinal edges. In the closed position, the second sidewalls 11 abut on the outside against the first sidewalls 9, while the front edge 8 abuts, by an upper edge thereof, against the inside of the top face 10 of the second closing part 5. The bottom side 12 of the intermediate part 4 constitutes the fourth wall of the storage device 1 in closed condition, as a result of which it is closed in an entirely waterproof and dustproof manner. The receiving means 13 for the data carrier 2, which will be further explained hereinbelow, are included in the intermediate part 4 and, when the storage device 1 is in the closed position, are included in the inner space 14 thereof, optionally together with a data carrier received therein.
The intermediate part 4 comprises two spaced-apart wall parts 15, interconnected by transverse partitions 16. At the side remote from the pivots 6, the walls 15 comprise toothed clamping projections 17, with two clamping projections 17 being in each case positioned directly opposite each other. Enclosed between the clamping projections 17 is a groove 18 having a width B which is slightly smaller than the thickness D of the data carrier 2 that is to be stored in the storage device.
In the embodiment shown in FIG. 3, the groove 18 extends along a segment of a circle having a radius R approximately corresponding to the radius R of a circular data carrier to be received therein, such as a CD. The circular segment includes an angle α of less than 180°. The angle a included is preferably about 120°, because in such an embodiment, sufficient clamping force can readily be obtained with a maximum groove length without the width of the intermediate part 4 having to be greater than the diameter 2 R of the data carrier 2. In the embodiment shown in FIG. 3, five pairs of clamping projections 17 are provided, but this number can of course be freely chosen. As the occasion arises, even one pair of clamping projections 17 may suffice, in which case the clamping projections may extend throughout the length of the groove 18.
FIG. 4 shows, in section, a closure 23, comprising an opening 24 in the second closing part 5, adjacent the longitudinal edge, remote from the pivots, of the top face 10 thereof. In a position corresponding to the opening 24 at least in the closed position of the storage device 1, 50, the first closing part 3 comprises two resilient fingers 25 located in the plane of the front edge 8. The resilient fingers 25 extend parallel to each other from a distance below the upper edge 26 of the front edge 8 to a position slightly thereabove, with two guide spheres 27 being provided at the top side. The opening 24 has a width such that the spheres can only be pressed therethrough after having been moved towards each other slightly. The edges 28 of the opening 24 are upwardly inclined so that the opening at the top side facing away from the first closing part 3 is larger than at the side facing the first closing part 3. This allows the guide spheres 27, after having passed the relatively narrow bottom side of the opening 24, to rebound outwards in the direction of their original position, whereby the first closing part 3 is secured on the second closing part 5. Because the resilient fingers 25 are located in the plane of the front edge or, optionally, of the sidewalls, a large number of such closures 23 can in the first place readily be included and, moreover, they can be integrally formed therewith during the injection molding process in a cheap manner and without any additional measures. After all, the relief thereof is possible in a simple manner.
The closing parts 3 and/or 5 can comprise support means for a data carrier 2 for supporting, at a distance from the intermediate part 4, the circumferential edge 19 of the data carrier 2 when the storage device 1 is in its closed position.
The pivots 6 are for instance shaped as V-shaped grooves, while a relatively thin bottom part can act as deformation element.
The closing parts 3, 5 are provided, in a conventional manner, with means for receiving text booklets, labels, librettos and like added information means.
An assembly according to the invention can be used as follows:
In an injection molding machine, a storage device 1, 50, 70 is manufactured in one production pass and then fed to a packaging line, with the closing parts 3, 5 lying flat on a conveying means and the intermediate part 4 extending approximately vertically and being open towards the top (FIG. 2). A data carrier 2 is simply inserted into the receiving means 13 by pressing a circumferential edge 19 thereof between the clamping projections 17 and pushing it further in the direction of the bottom 20 of the groove 18. This causes the clamping projections 17 to be slightly pressed apart, which creates a clamping force resulting from the deformation forces. This involves the clamping projections 17 being pressed against the flat outer surfaces 21 of the data carrier. The longitudinal edges 22, remote from the pivots 6, of the clamping projections 17 are beveled inwardly (FIG. 2A), as a result of which the data carrier can readily be pressed therethrough. The groove has a depth such that data-carrying parts K are not reached by the clamping projections 17. Next, any books and the like can be disposed in the receiving means intended therefor.
Because the clamping projections 17 need to be deformed only in a direction P transverse to the surface of the data carrier 2, the width S of the clamping projections 17 can be chosen relatively arbitrarily, so that in each case an optimum clamping force can be obtained, depending on the data carrier to be clamped and the possible height of the clamping projections 17. Because the wall parts 15 are spaced apart, no substantial differences in wall thickness occur in the storage device, while, moreover, relief problems of the mold are prevented, so that, in terms of injection molding engineering, the storage device is simple. As the clamping projections 17 are arranged so as to be substantially opposite each other, deformation of the edge of the data carrier 2 is prevented.
After the data carrier 2 has been inserted between the clamping projections 17, the closing parts 3, 5 are pivoted in the direction of the intermediate part 4 and the data carrier 2 so that the or each closure 23 is closed. On the outsides of the storage device, stickers or prints can for instance be provided, while they can also embossed or be provided with a print provided through in-mold labeling. After this, the assembly is ready for use.
A user can open the closed storage device in a simple manner by pivoting the closing parts apart. This involves the or each closure 23 being automatically unlocked due to the fact that the guide spheres 27 are pressed towards each other. By pivoting the closing parts 3, 5 away, the intermediate part 4 with the data carrier 2 included therein is released. This data carrier 2 can be gripped from two sides and pulled away through exertion of a force F in the direction away from the groove 18 and lying in the plane of the data carrier 2. After the data carrier 2 has been pulled away, the clamping projections 17 rebound into their starting positions. The data carrier 2 can readily be placed back by following the above steps in reverse order.
FIG. 5 gives an alternative embodiment of a storage device according to the invention. Here, two intermediate parts 4 are pivotally connected to each other and to the first 3 and the second closing part 5 respectively. This enables two data carriers to be stored side by side in the storage device. As the two intermediate parts are pivotable relative to each other, the two data carriers can be engaged on two sides without the other data carrier being in the way. In this manner, it is of course also possible to include several intermediate parts, side by side, to form a series of stored data carriers.
FIG. 6 shows a further alternative embodiment of a storage device 70, with data carrier 2 included therein. In this relatively simple and compact embodiment, the clamping projections 17 are directly disposed in three parts on the intermediate part 4, so that the circumferential edge of the data carrier 2 approximately abuts against the center part 4. Hence, the groove 18 lies closely against the center part and has two interrupted walls. The projections 17 slightly diverge at their free ends 30, creating a lead-in opening for the data carrier 2 to the clamping parts 31 of the projections 17, which lead-in opening converges in the direction of the center part 4.
Variations are possible within the scope of the present invention. For instance, the or each intermediate part may be fixedly disposed relative to the other parts, and, moreover, two or more grooves may be included side by side in the same plane in an intermediate part, for instance for storing relatively small data carriers side by side. Further, other shapes of storage devices may be chosen, for instance partially round or oval. The intermediate part 4 may be of a peg-shaped design, so that for instance by pressing together a part of the wall parts 15, the clamping projections 17 are pressed slightly apart and the data carrier 2 can be secured between the clamping projections 17 without sliding contact. Further, other materials may of course be used for the storage device, for instance completely biodegradable plastics, while in particular the closing parts may be of both transparent and opaque or entirely non-transparent design. Further, different closures may be used for the storage device, while, moreover, means may be provided for securing the intermediate part against one or both of the closing parts. These and many comparable variations are understood to fall within the framework of the invention.
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An assembly of at least one plate-shaped data carrier and a box-shaped storage device, wherein the storage device comprises two pivotally connected closing parts, which, in a closing position, together determine a receiving space for the or each data carrier and can be brought into an opened position for positioning or removing the or each data carrier, wherein resilient clamping projections are included for clampingly securing the or each plate-shaped data carrier, which can together be accommodated within the storage device, wherein the resilient clamping projections extend on either side of a groove, wherein the groove is adapted to receive at least a portion of a circumferential edge of the data carrier, and wherein the clamping projections are adapted to engage either side of the part of the data carrier that is received in the groove, wherein the data carrier is withdrawable from between the clamping projections through a force in a direction approximately parallel to the plane of the data carrier.
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FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a metal coordination compound, an organic luminescence device using the metal coordination compound and a display apparatus using the device. More specifically, the present invention relates to an organic metal coordination compound having a formula (1) appearing hereinafter as a luminescence material so as to allow stable luminescence efficiency, an organic luminescence device using the metal coordination compound and a display apparatus including the luminescence device.
An organic electroluminescence (EL) device has been extensively studied as a luminescence device with a high responsiveness and high efficiency.
The organic EL device generally has a sectional structure as shown in FIG. 1A or 1 B (e.g., as described in “Macromol. Symp.”, 125, pp. 1–48 (1997)).
Referring to the figures, the EL device generally has a structure including a transparent substrate 15 , a transparent electrode 14 disposed on the transparent substrate 15 , a metal electrode 11 disposed opposite to the transparent electrode 14 , and a plurality of organic (compound) layers, as luminescence function layers, disposed between the transparent electrode 14 and the metal electrode 11 .
Referring to FIG. 1A , the EL device in this embodiment has two organic layers including a luminescence layer 12 and a hole transport layer 13 .
The transparent electrode 14 may be formed of a film of ITO (indium tin oxide) having a larger work function to ensure a good hole injection performance into the hole transport layer. On the other hand, the metal electrode 11 may be formed of a layer of aluminum, magnesium, alloys thereof, etc., having a smaller work function to ensure a good electron injection performance into the organic layer(s).
These (transparent and metal) electrodes 14 and 11 may be formed in a thickness of 50–200 nm.
The luminescence layer 12 may be formed of, e.g., aluminum quinolinol complex (representative example thereof may include Alq3 described hereinafter) having an electron transporting characteristic and a luminescent characteristic. The hole transport layer 13 may be formed of, e.g., biphenyldiamine derivative (representative example thereof may include α-NPD described hereinafter) having an electron donating characteristic.
The above-described EL device exhibits a rectification characteristic, so that when an electric field is applied between the metal electrode 11 as a cathode and the transparent electrode 14 as an anode, electrons are injected from the metal electrode 11 into the luminescence layer 12 and holes are injected from the transparent electrode 14 .
The thus-injected holes and electrons are recombined within the luminescence layer 12 to produce excitons placed in an excited state, thus causing luminescence at the time of transition of the excitons to a ground state. At that time, the hole transport layer 13 functions as an electron-blocking layer to increase a recombination efficiency at the boundary between the luminescence layer 12 and the hole transport layer 13 , thus enhancing a luminescence efficiency.
Referring to FIG. 1B , in addition to the layers shown in FIG. 1A , an electron transport layer 16 is disposed between the metal electrode 11 and the luminescence layer 12 , whereby an effective carrier blocking performance can be ensured by separating functions of luminescence, electron transport and hole transport, thus allowing effective luminescence.
The electron transport layer 16 may be formed of, e.g., oxadiazole derivatives.
In ordinary organic EL devices, fluorescence caused during a transition of luminescent center molecule from a singlet excited state to a ground state is used as luminescence.
On the other hand, different from the above fluorescence (luminescence) via singlet exciton, phosphorescence (luminescence) via triplet exciton has been studied for use in organic EL device as described in, e.g., “Improved energy transfer in electrophosphorescent device” (D. F. O'Brien et al., Applied Physics Letters, Vol. 74, No. 3, pp. 442–444 (1999)) and “Very high-efficiency green organic light-emitting devices based on electrophosphorescence” (M. A. Baldo et al., Applied Physics Letters, Vol. 75, No. 1, pp. 4–6 (1999)).
The EL devices shown in these documents may generally have a sectional structure shown in FIG. 1C .
Referring to FIG. 1C , four organic layers including a hole transfer layer 13 , a luminescence layer 12 , an exciton diffusion-prevention layer 17 , and an electron transport layer 16 are successively formed in this order on the transparent electrode (anode) 14 .
In the above documents, higher efficiencies have been achieved by using four organic layers including a hole transport layer 13 of α-NPD (shown below), an electron transport layer 16 of Alq3 (shown below), an exciton diffusion-prevention layer 17 of BPC (shown below), and a luminescence layer 12 of a mixture of CPB (shown below) as a host material with Ir(ppy) 3 (shown below) or PtOEP (shown below) as a guest phosphorescence material doped into CBP at a concentration of ca. 6 wt. %.
Alq3: tris(8-hydroxyquinoline) aluminum (aluminum-quinolinol complex), α-NPD: N4,N4′-di-naphthalene-1-yl-N4,N4′-diphenyl-biphenyl-4,4′-diamine (4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl), CBP: 4,4′-N,N′-dicarbazole-biphenyl, BCP: 2,9-dimethyl-4,7-diphenyl-1,10-phenan-throline, Ir(ppy) 3 : fac tris(2-phenylpyridine)iridium (iridium-phenylpyridine complex), and PtOEP: 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum (platinum-octaethyl porphine complex).
The phosphorescence (luminescence) material used in the luminescence layer 12 has particularly attracted notice. This is because the phosphorescence material is expected to provide a higher luminescence efficiency in principle.
More specifically, in the case of the phosphorescence material, excitons produced by recombination of carriers comprise singlet excitons and triplet excitons presented in a ratio of 1:3. For this reason, when fluorescence caused during the transition from the singlet excited state to the ground state is utilized, a resultant luminescence efficiency is 25% (as upper limit) based on all the produced excitons in principle.
On the other hand, in the case of utilizing phosphorescence caused during transition from the triplet excited state, a resultant luminescence efficiency is expected to be at least three times that of the case of fluorescence in principle. In addition thereto, if intersystem crossing from the singlet excited state (higher energy level) to the triplet excited state is taken into consideration, the luminescence efficiency of phosphorescence can be expected to be 100% (four times that of fluorescence) in principle.
The use of phosphorescence based on transition from the triplet excited state has also been proposed in, e.g., Japanese Laid-Open Patent Application (JP-A) 11-329739, JP-A 11-256148 and JP-A 8-319482.
However, the above-mentioned organic EL devices utilizing phosphorescence have accompanied with problems of a lower luminescence efficiency and stability thereof (luminescent deterioration) particularly in an energized state.
The reason for luminescent deterioration has not been clarified as yet but may be attributable to such a phenomenon that the life of triplet exciton is generally longer than that of singlet exciton by at least three digits, so that molecule is placed in a higher-energy state for a long period to cause reaction with ambient substance, formation of exciplex or excimer, change in minute molecular structure, structural change of ambient substance, etc.
Accordingly, a phosphorescence material for the (electro)phosphorescence EL device is required to provide a higher luminescence efficiency and a higher stability, to the EL device.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a metal coordination compound as a material suitable for an organic layer of a luminescence device capable of providing a high-efficiency luminescent state at a high brightness (or luminance) for a long period while maintaining stability of the device.
Another object of the present invention is to provide a metal coordination compound allowing a higher phosphorescence yield and controlled emission (luminescence) wavelength as a phosphorescence (luminescence) material.
A further object to the present invention is to provide a metal coordination compound, as a multi-functional luminescence material, having not only a controlled luminescent characteristic but also controlled electrical characteristic, in view of a significance of the electrical characteristic of a luminescence material alone in the case where the luminescence material is employed in an organic EL device and is supplied with a current for luminescence.
A still further object of the present invention is to provide an organic luminescence device using the metal coordination compound and a display apparatus including the organic luminescence device.
According to the present invention, there is provided a metal coordination compound represented by the following formula (1):
LmML′n (1),
wherein M denotes Ir, Pt, Rh or Pd; L denotes a bidentate ligand; L′ denotes a bidentate ligand different from L; m is an integer of 1, 2 or 3; and n is an integer of 0, 1 or 2 with the proviso that the sum of m and n is 2 or 3,
the partial structure MLm being represented by a formula (2) or a formula (3) shown below, and the partial structure ML′n being represented by a formula (4) or a formula (5) shown below:
wherein CyN1, CyN2 and CyN3 independently denote a substituted or unsubstituted cyclic group containing a nitrogen atom connected to M; CyN4 denotes a cyclic group containing 8-quinoline or its derivative having a nitrogen atom connected to M; CyC1, CyC2 and CyC3 independently denote a substituted or unsubstituted cyclic group containing a carbon atom connected to M,
each of substituents for CyN1, CyN2, CyN3, CyC1, CyC2 and CyC3 being selected from the group consisting of a halogen atom; cyano group; nitro group; a trialkylsilyl group containing three linear or branched alkyl groups each independently having 1–8 carbon atoms; a linear or branched alkyl group having 1–20 carbon atoms capable of including one or at least two non-neighboring methylene groups which can be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH— or —C≡C— and capable of including a hydrogen atom which can be replaced with a fluorine atom; and an aromatic ring group capable of having a substituent selected from the group consisting of a halogen atom; cyano group; nitro group; and a linear or branched alkyl group having 1–20 carbon atoms capable of including one or at least two non-neighboring methylene groups which can be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH— or —C≡C— and capable of including a hydrogen atom which can be replaced with a fluorine atom,
CyN1 and CyC1 being connected via a covalent group containing X which is represented by —O—, —S—, —CO—, —C(R1)(R2)— or —NR— where R1, R2 and R independently denote a hydrogen atom, a halogen atom, an alkyl group, an alkyl group substituted with a halogen atom, a phenyl group or a naphthyl group, and
CyN2 and CyC2, and CyN3 and CyC3 being independently connected via a covalent bond,
with the proviso that the metal coordination compound is represented by the formula (2) when n is 0.
The metal coordination compound of the present invention exhibits phosphorescence at the time of energy transfer from an excited state to a ground state to provide a high luminescence efficiency.
According to the present invention, there is also provided an organic luminescence device, comprising: a substrate, a pair of electrodes disposed on the substrate, and a luminescence function layer disposed between the pair of electrodes comprising at least one species of an organic compound,
wherein the organic compound comprises a metal coordination compound represented by the following formula (1):
LmML′n (1),
wherein M denotes Ir, Pt, Rh or Pd; L denotes a bidentate ligand; L′ denotes a bidentate ligand different from L; m is an integer of 1, 2 or 3; and n is an integer of 0, 1 or 2 with the proviso that the sum of m and n is 2 or 3,
the partial structure MLm being represented by a formula (2) or a formula (3) shown below, and the partial structure ML′n being represented by a formula (4) or a formula (5) shown below:
wherein CyN1, CyN2 and CyN3 independently denote a substituted or unsubstituted cyclic group containing a nitrogen atom connected to M; CyN4 denotes a cyclic group containing 8-quinoline or its derivative having a nitrogen atom connected to M; CyC1, CyC2 and CyC3 independently denote a substituted or unsubstituted cyclic group containing a carbon atom connected to M,
each of substituents for CyN1, CyN2, CyN3, CyC1, CyC2 and CyC3 being selected from the group consisting of a halogen atom; cyano group; nitro group; a trialkylsilyl group containing three linear or branched alkyl groups each independently having 1–8 carbon atoms; a linear or branched alkyl group having 1–20 carbon atoms capable of including one or at least two non-neighboring methylene groups which can be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH— or —C≡C— and capable of including a hydrogen atom which can be replaced with a fluorine atom; and an aromatic ring group capable of having a substituent selected from the group consisting of a halogen atom; cyano group; nitro group; and a linear or branched alkyl group having 1–20 carbon atoms capable of including one or at least two non-neighboring methylene groups which can be replaced with —O—, —S—, —CO—, —CO—O—, —O—CO—, —CH═CH— or —C≡C— and capable of including a hydrogen atom which can be replaced with a fluorine atom,
CyN1 and CyC1 being connected via a covalent group containing X which is represented by —O—, —S—, —CO—, —C(R1)(R2)— or —NR— where R1, R2 and R independently denote a hydrogen atom, a halogen atom, an alkyl group, an alkyl group substituted with a halogen atom, a phenyl group or a naphthyl group, and
CyN2 and CyC2, and CyN3 and CyC3 being independently connected via a covalent bond,
with the proviso that the metal coordination compound is represented by the formula (2) when n is 0.
By applying a voltage between the pair of electrodes of the organic luminescence device to cause phosphorescence from the organic compound layer (luminescence function layer) containing the metal coordination compound.
According to the present invention, there is further provided an image display apparatus including the organic luminescence device and means for supplying electrical signals to the organic luminescence device.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A , 1 B and 1 C are respectively a schematic sectional view of a layer structure of an organic luminescence device.
FIG. 2 is a schematic perspective view of an organic luminescence device of a single matrix-type used in Example 3 appearing hereinafter.
FIG. 3 is a waveform diagram of a driving signal employed in Example 3.
FIG. 4A shows luminescence spectrum diagram of a phenylpyridine-based Ir complex (Ir(ppy) 3 ), and
FIG. 4B shows a luminescence spectrum diagram of a thienylpyridine-based Ir complex (Ir(thpy) 3 ).
FIG. 5 shows a luminescence spectrum diagram of 2-benzylpyridine Ir complex used in Example 10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the case where a luminescence layer for an organic EL device is formed of a carrier transporting host material and a phosphorescent guest material, a process of emission of light (phosphorescence) may generally involve the following steps:
(1) transport of electron and hole within a luminescence layer, (2) formation of exciton of the host material, (3) transmission of excited energy between host material molecules, (4) transmission of excited energy from the host material molecule to the guest material molecule, (5) formation of triplet exciton of the guest material, and (6) emission of light (phosphorescence) caused during transition from the triplet excited state to the ground state of the guest material.
In the above steps, desired energy transmission and luminescence may generally be caused based on various quenching and competition.
In order to improve a luminescence efficiency of the EL device, a luminescence center material per se is required to provide a higher yield of luminescence quantum. In addition thereto, an efficient energy transfer between host material molecules and/or between host material molecule and guest material molecule is also an important factor.
Further, the above-described luminescent deterioration in energized state may presumably relate to the luminescent center material per se or an environmental change thereof by its ambient molecular structure.
The metal coordination compound represented by the above formula (1) according to the present invention causes phosphorescence (luminescence) and is assumed to have a lowest excited state comprising a triplet excited state liable to cause metal-to-ligand charge transfer (MLCT* state) or π–π* state as a ligand-centered triplet excited state. The phosphorescent emission of light (phosphorescence) is caused to occur during the transition from the MLCT* state or π–π* state to the ground state.
The metal coordination compound of formula (1) according to the present invention has been found to provide a higher phosphorescence yield of at least 0.01 and a shorter phosphorescence life of 1–100 μsec.
The shorter phosphorescence life is necessary to provide a resultant EL device with a higher luminescence efficiency. This is because the longer phosphorescence life increases molecules placed in their triplet excited state which is a waiting state for phosphorescence, thus lowering the resultant luminescence efficiency particularly at a higher current density.
Accordingly, the metal coordination compound of formula (1) according to the present invention is a suitable luminescent material for an organic EL device with a higher phosphorescence yield and a shorter phosphorescence life.
Further, due to the shorter phosphorescence life, molecules of the metal coordination compound of formula (1) have a shorter time period wherein they stay in the triplet excited state, i.e. a higher energy state, thus providing the resultant EL device with improved durability and less deterioration in device characteristic. In this regard, the metal coordination compound according to the present invention has been substantiated to exhibit excellent stability of luminance as shown in Examples described hereinafter.
The organic luminescence device according to the present invention has a layer structure wherein an organic compound layer (luminescence function layer) comprising the metal coordination compound of the formula (1) is sandwiched between a pair of oppositely disposed electrodes as shown in FIGS. 1A to 1C . The organic luminescence device exhibits phosphorescence from the organic compound layer by applying a voltage between the pair of electrodes.
The metal coordination compound of the formula (1) according to the present invention used in the organic luminescence device (EL device) as a luminescence function material, particularly a luminescent material may be roughly classified into the following two compounds:
(1) a metal coordination compound having a molecular structure containing the same species of plural (two or three) ligands, and (2) a metal coordination compound having a molecular structure containing different species of plural ligands.
In the present invention, it is possible to appropriately design a molecular structure of metal coordination compound so as to provide a stably high luminescence efficiency and maximum luminescence wavelength by using ligands different in structure in either case (of the above (1) and (2)).
In the case (1) using the same species of ligands, it is possible to provide a smaller half-width of luminescence spectrum and a higher color purity.
Further, in the case (2) using different species of ligands, it is possible to employ two different ligands for the metal coordination compound of the formula (1), thus imparting a plurality of functions (multi-function) to the metal coordination compound based on the respective features of the ligands. The impartition of multi-function is a characteristic feature of the use of different species of ligands. Particularly, in the case where the metal coordination compound having different species of ligands is used in an organic EL device, incorporation into the metal coordination compound of different species of ligands capable of imparting controlled luminescence and current characteristics to the EL device is very advantageous to the EL device since device characteristics of the EL device is largely affected by not only the luminescence characteristic but also the current characteristic.
An organic luminescence device using a phosphorescence material having different ligand structure has been described in M. E. Thompson et al., “Electrophotophorescent Organic Light Emitting Diodes” (Conference record of the 20th International Display Research Conference), pp. 337–340 (2000). In this document, Ir coordination compounds having luminescent ligands containing a phenylpyridine skeleton or a thienylpyridine skeleton and an additional ligand containing an acetylacetone skeleton. By using the Ir coordination compounds, a synthesis yield is improved without lowering a luminescence characteristic compared with Ir complex having (identical) three ligands of phenylpyridine (tris-acetylacetonato-Ir complex).
However, the tris-acetylacetonato-Ir complex exhibits no or a slight phosphorescence and has no carrier (hole/electron) transport performance.
In the above document, the acetylacetone ligand ((acac)ligand) is employed for the purpose of improving the synthesis yield without impairing the luminescence performance as described above, thus failing to positively suggesting improvement in device characteristics of an organic EL device.
According to our experiment, the device characteristics of the organic EL device have been found to be improved by imparting functions described below to different two ligands constituting a different ligand structure.
In order to determine an inherent feature of a ligand, at first, a metal coordination compound having one metal connected with the same species of ligands is synthesized and subjected to measurement of its characteristics (affected by a combination of the metal with the ligands), such as a (maximum) luminescence wavelength (emission wavelength), a luminescence yield, an electron transfer performance, a hole transfer performance and a thermal stability.
In this regard, in order to determine the luminescence characteristics including the luminescence wavelength and yield, a characteristic of luminescence molecules placed in a minimum excited state is an important factor.
As described above, the minimum excited state of the metal coordination compound of the formula (1) according to the present invention is the MLCT excited state or the ligand-centered excited state. In the case of a phosphorescence material, the MLCT excited state is generally advantageous thereto since the phosphorescence material (placed in the MLCT excited state) has a higher luminescence transition probability and a stronger luminescence performance in many cases.
Based on a combination of ligands and a (central) metal, a resultant metal coordination compound is determined whether its excited state is the MLCT excited state or the ligand-centered excited state.
Herein, the terms “MLCT (metal to ligand charge transfer) excited state” refers to an excited state formed by localization of electron orbit of molecules constituting the metal coordination compound towards the ligand side, thus causing a transfer of one electron side, thus causing a transfer of one electron from the metal to the ligand. On the other hand, the term “ligand-centered excited state” refers to an excited state formed within the ligands without being directly affected by the metal at the time of excitation. Generally, an electron is excited from bonding π-orbital to nonbonding π-orbital. Accordingly, the ligand-centered excited state is also called “π–π* excited state”.
The carrier (hole/electron) transfer performance or ability may, e.g., be evaluated by measuring an increased amount of a current value flowing between a pair of electrodes sandwiching an organic compound layer (luminescence function layer) containing dispersed metal coordination compound having the same species of ligands, relative to that in the case of using no metal coordination compound.
Further, it is possible to determine whether H the organic compound layer is an electron transport layer or a hole transport layer by comparing a current characteristic of an organic luminescence device having a multi-layer structure including two organic compound layers sandwiching a luminescence layer therebetween with respect to various organic compounds constituting organic compound layers.
As described above, it becomes possible to characterize ligands constituting the metal coordination compound of the present invention by appropriately changing a combination of the metal and ligands.
Then, in order to improve the luminescence characteristics of a metal coordination compound having a different ligand structure, we presume that it is preferred to smoothly effect excited energy transition between ligands placed in their excited states to cause luminescence based on a particular ligand while minimizing the number of luminescent ligand.
More specifically, when a metal coordination compound having three ligands including one luminescent ligand is placed in excited state, excited energy is transferred from two ligands to one luminescent ligand, thus allowing a monochromatic luminescent color and an increased color purity. Further, it is expected that the use of one luminescent ligand decreases a probability of occurrence of energy transition between spatially adjacent molecules of the metal coordination compound, thus resulting in a decrease in quenching or deactivated energy.
Accordingly, in the present invention, a preferred class of combinations of a plurality of ligands may include:
(a) a combination of ligands including at least one ligand capable of being placed in the MLCT excited state, (b) a combination of ligands including both of a luminescent ligand and a carrier transport ligand, (c) a combination of ligands including a first ligand providing a longer maximum luminescence wavelength λ1 (i.e., smaller excited energy) and a second ligand providing a shorter maximum luminescence wavelength λ2 (<λ1) (i.e., larger excited energy) wherein the number of the first ligand is smaller than that of the second ligand, and (d) a combination of ligands including a stronger luminescent ligand and a weaker luminescent ligand wherein the number of the stronger luminescent ligand is smaller than that of the weaker luminescent ligand.
The above ligand combinations (a) to (d) will be described below more specifically by taking Ir complexes as an example.
The metal coordination compounds having the above structural formulas 41 to 51 may be classified as follows.
Combination
Formula
(a)
41, 42, 43
(b)
44, 45
(c)
46, 47, 48, 49
(d)
48, 50
The metal coordination compounds of the formulas 41–51 includes those which can be embraced in a plurality of the combinations (a)–(d).
Combination (a)
The metal coordination compound of the formula 41 has two phenylpyridine ligands and one thienylpyridine ligand respectively connected to Ir (center metal). When the metal coordination compound is excited, the phenylpyridine ligands are placed in the MLCT excited state and the thienylpyridine ligand is placed in the ligand-centered excited state.
The excited state (MLCT or ligand-centered excited state) is identified based on shapes of emission spectra of Ir complex having three phenylpyridine skeletons (Ir(ppy) 3 ) and Ir complex having three thienylpyridine skeletons (Ir(thpy) 3 ), diagrams of which are shown in FIGS. 4A and 4B , respectively.
Referring to FIG. 4A , Ir(ppy) 3 shows no peak other than a main peak. On the other hand, as shown in FIG. 4B , Ir(thpy) 3 shows a sub-peak (or shoulder) other than a main peak on the longer wavelength side. This sub-peak is resulting from a vibrational level of an aromatic ligand and thus is not observed in the case of the MLCT excited state.
In the case of phosphorescence, compared with the case of the ligand-centered excited state, the case of the MLCT excited state is considerably allowed to exhibit transition with luminescence (phosphorescence) from the excited state to the ground state. Further, a probability of such transition is higher than that of transition with no radiation, thus generally providing a higher phosphorescence yield.
Ir(ppy) 3 shows no sub-peak as in the case of Ir(thpy) 3 , thus being identified to be placed in the MLCT excited state.
Accordingly, in the case of the metal coordination compound of the formula 41, when the phenylpyridine ligand is first excited, the excitation energy is not quenched or deactivated but is quickly intramolecular-transferred to the thienylpyridine ligand to place the thienylpyridine ligand in an excited state. This is because the triplet energy level of phenylpyridine is higher than that of thienylpyridine.
Even in both the case of an organic EL device and the case of photoluminescence (PL) in a photo-excitation solution, luminescence at 550 nm resulting from the thienylpyridine ligand is observed.
Similarly, the 8-quinolinol ligand in the metal coordination compound of the formula 42 and the benzothienylpyridine ligand in the metal coordination compound of the formula 43 are ligands placed in the ligand-centered excited state. In these cases of using the metal coordination compounds of the formula 42 and 43, luminescences resulting from the 8 -quinolinol ligand and the benzothienylpyridine ligand as a longer-wavelength luminescent ligand are observed, respectively.
In the case where a ligand in the MLCT excited state provides a longer maximum luminescence wavelength, luminescence resulting from the ligand in the MLCT excited state.
Further, for example, in the case of the metal coordination compound of the formula 48 having the 4-fluorophenylpyridine ligand and the 4 -methylphenylpyridine ligand both in the MLCT excited state, quenching with no luminescence is not readily caused to occur.
The maximum luminescence wavelength of the 4-fluorophenylpyridine is shorter than (i.e., excitation energy level thereof is higher than) that of the 4-methylphenylpyridine. Accordingly, even when either ligand is excited, excitation energy is intramolecular-transferred to the 4-methylphenyl-pyridine ligand with a lower excitation energy level to cause luminescence resulting from the 4-methylphenylpyridine. The metal coordination compound of the formula 48 is thus placed in the MLCT excited state, thus not readily causing quenching with no radiation to allow a high-efficiency luminescence.
Accordingly, when the metal coordination compound of the present invention has a different ligand structure including a ligand capable of being placed in the MLCT excited state, it becomes possible to effect intramolecular energy transition at a high efficiency, thus ensuring a high phosphorescence yield.
Combination (b)
The metal coordination compound of the formula 44 has the f-quinolinol ligand as an electron transport ligand and the benzothienylpyridine ligand as a luminescent ligand. When the metal coordination compound of the formula 44 is dispersed in the luminescence layer 12 of the organic EL device shown in FIG. 1C , it is possible to improve a luminescence efficiency compared with the case of using a metal coordination compound having the same ligand structure comprising three f-quinolinol ligands (i.e., tris-8-quinolinolato-Ir complex).
Further, when compared with an organic EL device using no luminescence material (the metal coordination compound of the formula 44 in this case), the organic EL device using the metal coordination compound of the formula 44 effectively improves a resultant current density under application of an identical voltage. This may be attributable to such a mechanism that the electron transport 8-quinolinol ligand allows supply of electrons to the luminescence layer (into which carrier electrons are ordinarily to readily injected) by dispersing the metal coordination compound of the formula 44 in the luminescence layer, thus forming excitons by combination with holes to ensure efficient luminescence based on the luminescence benzothienylpyridine ligand.
The benzothienylpyridine ligand also exhibits a hole transport performance. In the metal coordination compound of the formula 45, the benzothienylpyridine ligand has a hole transport function.
Combination (c)
The metal coordination compound of the formula 46 has the thienylpyridine ligand and the benzothienylpyridine ligand.
An Ir complex having three thienylpyridine ligands and an Ir complex having three benzothienyl-pyridine ligands causes phosphorescence at maximum luminescence wavelengths of 550 nm and 600 nm, respectively. Accordingly, the latter Ir complex has a longer maximum luminescence wavelength and a smaller lowest excitation energy (triplet energy in this case). Luminescence resulting from the benzothienyl-pyridine ligand is observed both in the case of an organic EL device using the metal coordination compound of the formula 46 and in the case of PL (photoluminescence) in a photo-excitation solution thereof.
When an organic EL device shown in FIG. 1C is prepared by using the metal coordination compound of the formula 46, it is possible to obtain a high luminescence efficiency. This may be attributable to such a mechanism that, compared with a metal coordination compound having (identical) three benzothienylpyridine ligands (luminescent ligands), the number of luminescent ligand in the metal coordination compound of the formula 46 is ⅓ of the metal coordination compound having three benzothienyl-pyridine ligands to decrease a probability of formation of quenching path with no luminescence by intermolecular interaction with ambient molecules.
Accordingly, it becomes possible to realize a high luminescence efficiency by decreasing the number of the longer-wavelength luminescent ligand relative to that of the shorter-wavelength luminescent ligand.
With respect to the metal coordination compound of the formula 49, the benzylpyridine ligand exhibits a blue luminescence characteristic (emission peak wavelength: 480 nm) and the phenylpyridine ligand exhibits a green luminescence characteristic (emission peak wavelength: 515 nm).
As a result, excitation energy is concentrated on the phenylpyridine ligand, thus ensuring stable luminescence resulting from the phenylpyridine ligand.
Combination (d)
The metal coordination compound of the formula 50 has the thienyl-4-trifluoromethylpyridine ligand and the benzothienylpyridine ligand.
According to our experiment as to luminescence characteristic in a solution (e.g., in deoxidized toluene), a photo-excitation phosphorescence yield in the solution of an Ir complex having three thienyl-4-trifluoromethylpyridine ligands is smaller than that of an Ir complex having three benzothienylpyridine ligands. Accordingly, the benzothienylpyridine ligand is a relatively stronger luminescent ligand compared with the thienyl-4-trifluoromethylpyridine ligand. Further, the former ligand also provides a relatively longer maximum luminescence wavelength (i.e., a relatively lower excitation energy level). For this reason, luminescence from the metal coordination compound of the formula 49 is one resulting from the benzo-thienylpyridine ligands based on intramolecular energy transfer.
By using the metal coordination compound of the formula 49 in a luminescence layer 12 for an organic EL device shown in FIG. 1C , a high luminescence efficiency is achieved.
Accordingly, it is possible to improve a luminescence efficiency by decreasing the number (1 in this case) of stronger luminescent ligand and longer-wavelength luminescent ligand.
As described above, the metal coordination compound of the present invention satisfying at least one of the above-mentioned combinations (a) to (d) effectively functions as a luminescence function material and provides a resultant organic EL device with a high luminescence efficiency. In the present invention, it is generally expected to increase the luminescence efficiency by ca. 20% when compared with the case of using a metal coordination compound having identical three luminescent ligands, but a degree of increase in luminescence efficiency may vary depending on species of the metal and ligands.
The above-mentioned high-efficiency organic luminescence device may be applicable to various products requiring energy saving and high luminescence, such as light sources for a display apparatus, illumination apparatus, printers, etc., and a backlight for a liquid crystal display apparatus.
When the organic luminescence device of the present invention is used as an image display apparatus, it becomes possible to provide flat-panel displays with advantages such as a good energy saving performance, high visibility, and lightweight properties.
The organic luminescence device of the present invention is also prepared in a single matrix-type display device using intersecting stripe electrodes at right angles or an active matrix-type display device including a matrix of pixels each provided with, e.g., at least one TFT (thin film transistor), such as amorphous TFT or polycrystalline TFT.
When the organic luminescence device of the present invention is used as a light source for a printer, e.g., as a laser light source for a laser beam printer, independently addressable elements are arranged in an array and a photosensitive drum is subjected to desired exposure, thus effecting image formation. By the use of the organic luminescence device of the present invention, it becomes possible to considerably reduce the apparatus size (volume).
With respect to the illumination apparatus and the backlight, it is expected that the organic luminescence device of the present invention effectively exhibits an excellent energy saving effect.
Hereinbelow, specific examples of the metal coordination compound of the formula (1) according to the present invention will be shown in Table 1. The metal coordination compound of the present invention is however not restricted to these specific examples.
In Table 1, abbreviations Ph to Pz for CyN1, CyN2, CyN3, CyC1, CyC2 and CyC3 and those O to CR2 for —X— represent the following divalent groups, respectively.
Further, formulas (11) to (14) corresponding to the partial structure ML′n as the formula (5) (including CyN4 being 8-quinolinol skeleton or its derivative) shown as L′ in Table 1 for convenience represent the following structures, respectively.
Further, Example Compounds Nos. 215 to 218 and 746 include an acetylacetone ligand as L′ for another ligand of the formula (6).
TABLE 1
L
No
M
m
n
CyN1
CyC1
R1
R2
R3
R4
R5
R6
L′
1
Ir
3
0
Pr
O
Ph
H
H
H
H
2
Ir
3
0
Pr
O
Tn1
H
H
H
H
3
Ir
3
0
Pr
O
Tn2
H
H
H
H
4
Ir
3
0
Pr
O
Tn3
H
H
H
H
5
Ir
3
0
Pr
O
Qn1
H
H
H
H
6
Ir
3
0
Pr
O
Qn2
H
H
H
H
7
Ir
3
0
Pr
O
Qx
H
H
H
H
8
Ir
3
0
Pr
O
Qz1
—
H
H
H
9
Ir
3
0
Pr
O
Qz2
H
—
H
H
10
Ir
3
0
Pr
O
Cn1
—
H
H
H
11
Ir
3
0
Pr
O
Cn2
H
—
H
H
12
Ir
3
0
Pr
O
Pz
—
—
H
H
13
Ir
3
0
Pr
S
Ph
H
H
H
H
14
Ir
3
0
Pr
S
Tn1
H
H
H
H
15
Ir
3
0
Pr
S
Tn2
H
H
H
H
16
Ir
3
0
Pr
S
Tn3
H
H
H
H
17
Ir
3
0
Pr
S
Qn1
H
H
H
H
18
Ir
3
0
Pr
S
Qn2
H
H
H
H
19
Ir
3
0
Pr
S
Qx
H
H
H
H
20
Ir
3
0
Pr
S
Qz1
—
H
H
H
21
Ir
3
0
Pr
S
Qz2
H
—
H
H
22
Ir
3
0
Pr
S
Cn1
—
H
H
H
23
Ir
3
0
Pr
S
Cn2
H
—
H
H
24
Ir
3
0
Pr
S
Pz
—
—
H
H
25
Ir
3
0
Pr
NR
Ph
H
H
H
H
H
26
Ir
3
0
Pr
NR
Tn1
H
H
H
H
H
27
Ir
3
0
Pr
NR
Tn2
H
H
H
H
H
28
Ir
3
0
Pr
NR
Tn3
H
H
H
H
H
29
Ir
3
0
Pr
NR
Qn1
H
H
H
H
H
30
Ir
3
0
Pr
NR
Qn2
H
H
H
H
H
31
Ir
3
0
Pr
NR
Qx
H
H
H
H
H
32
Ir
3
0
Pr
NR
Qz1
—
H
H
H
H
33
Ir
3
0
Pr
NR
Qz2
H
—
H
H
H
34
Ir
3
0
Pr
NR
Cn1
—
H
H
H
H
35
Ir
3
0
Pr
NR
Cn2
H
—
H
H
H
36
Ir
3
0
Pr
NR
Pz
—
—
H
H
H
37
Ir
3
0
Pr
CO
Ph
H
H
H
H
38
Ir
3
0
Pr
CO
Tn1
H
H
H
H
39
Ir
3
0
Pr
CO
Tn2
H
H
H
H
40
Ir
3
0
Pr
CO
Tn3
H
H
H
H
41
Ir
3
0
Pr
CO
Qn1
H
H
H
H
42
Ir
3
0
Pr
CO
Qn2
H
H
H
H
43
Ir
3
0
Pr
CO
Qx
H
H
H
H
44
Ir
3
0
Pr
CO
Qz1
—
H
H
H
45
Ir
3
0
Pr
CO
Qz2
H
—
H
H
46
Ir
3
0
Pr
CO
Cn1
—
H
H
H
47
Ir
3
0
Pr
CO
Cn2
H
—
H
H
48
Ir
3
0
Pr
CO
Pz
—
—
H
H
49
Ir
3
0
Pr
CR2
Ph
H
H
H
H
H
H
50
Ir
3
0
Pr
CR2
Tn1
H
H
H
H
H
H
51
Ir
3
0
Pr
CR2
Tn2
H
H
H
H
H
H
52
Ir
3
0
Pr
CR2
Tn3
H
H
H
H
H
H
53
Ir
3
0
Pr
CR2
Qn1
H
H
H
H
H
H
54
Ir
3
0
Pr
CR2
Qn2
H
H
H
H
H
H
55
Ir
3
0
Pr
CR2
Qx
H
H
H
H
H
H
56
Ir
3
0
Pr
CR2
Qz1
—
H
H
H
H
H
57
Ir
3
0
Pr
CR2
Qx2
H
—
H
H
H
H
58
Ir
3
0
Pr
CR2
Cn1
—
H
H
H
H
H
59
Ir
3
0
Pr
CR2
Cn2
H
—
H
H
H
H
60
Ir
3
0
Pr
CR2
Pz
—
—
H
H
H
H
61
Ir
3
0
Pd
O
Ph
H
H
H
H
62
Ir
3
0
Pd
O
Tn1
H
H
H
H
63
Ir
3
0
Pd
O
Tn2
H
H
H
H
64
Ir
3
0
Pd
O
Tn3
H
H
H
H
65
Ir
3
0
Pd
S
Ph
H
H
H
H
66
Ir
3
0
Pd
S
Tn1
H
H
H
H
67
Ir
3
0
Pd
S
Tn2
H
H
H
H
68
Ir
3
0
Pd
S
Tn3
H
H
H
H
69
Ir
3
0
Pd
NR
Ph
H
H
H
H
H
70
Ir
3
0
Pd
NR
Tn1
H
H
H
H
H
71
Ir
3
0
Pd
NR
Tn2
H
H
H
H
H
72
Ir
3
0
Pd
NR
Tn3
H
H
H
H
H
73
Ir
3
0
Pd
CO
Ph
H
H
H
H
74
Ir
3
0
Pd
CO
Tn1
H
H
H
H
75
Ir
3
0
Pd
CO
Tn2
H
H
H
H
76
Ir
3
0
Pd
CO
Tn3
H
H
H
H
77
Ir
3
0
Pd
CR2
Ph
H
H
H
H
H
H
78
Ir
3
0
Pd
CR2
Tn1
H
H
H
H
H
H
79
Ir
3
0
Pd
CR2
Tn2
H
H
H
H
H
H
80
Ir
3
0
Pd
CR2
Tn3
H
H
H
H
H
H
81
Ir
3
0
Pr1
O
Ph
H
H
H
—
82
Ir
3
0
Pr1
O
Tn1
H
H
H
—
83
Ir
3
0
Pr1
O
Tn2
H
H
H
—
84
Ir
3
0
Pr1
O
Tn3
H
H
H
—
85
Ir
3
0
Pr1
S
Ph
H
H
H
—
86
Ir
3
0
Pr1
S
Tn1
H
H
H
—
87
Ir
3
0
Pr1
S
Tn2
H
H
H
—
88
Ir
3
0
Pr1
S
Tn3
H
H
H
—
89
Ir
3
0
Pr1
NR
Ph
H
H
H
—
H
90
Ir
3
0
Pr1
NR
Tn1
H
H
H
—
H
91
Ir
3
0
Pr1
NR
Tn2
H
H
H
—
H
92
Ir
3
0
Pr1
NR
Tn3
H
H
H
—
H
93
Ir
3
0
Pr1
CO
Ph
H
H
H
—
94
Ir
3
0
Pr1
CO
Tn1
H
H
H
—
95
Ir
3
0
Pr1
CO
Tn2
H
H
H
—
96
Ir
3
0
Pr1
CO
Tn3
H
H
H
—
97
Ir
3
0
Pr1
CR2
Ph
H
H
H
—
H
H
98
Ir
3
0
Pr1
CR2
Tn1
H
H
H
—
H
H
99
Ir
3
0
Pr1
CR2
Tn2
H
H
H
—
H
H
100
Ir
3
0
Pr1
CR2
Tn3
H
H
H
—
H
H
101
Ir
3
0
Pa
O
Ph
H
H
—
H
102
Ir
3
0
Pa
O
Tn1
H
H
—
H
103
Ir
3
0
Pa
O
Tn2
H
H
—
H
104
Ir
3
0
Pa
O
Tn3
H
H
—
H
105
Ir
3
0
Pa
S
Ph
H
H
—
H
106
Ir
3
0
Pa
S
Tn1
H
H
—
H
107
Ir
3
0
Pa
S
Tn2
H
H
—
H
108
Ir
3
0
Pa
S
Tn3
H
H
—
H
109
Ir
3
0
Pa
NR
Ph
H
H
—
H
H
110
Ir
3
0
Pa
NR
Tn1
H
H
—
H
H
111
Ir
3
0
Pa
NR
Tn2
H
H
—
H
H
112
Ir
3
0
Pa
NR
Tn3
H
H
—
H
H
113
Ir
3
0
Pa
CO
Ph
H
H
—
H
114
Ir
3
0
Pa
CO
Tn1
H
H
—
H
115
Ir
3
0
Pa
CO
Tn2
H
H
—
H
116
Ir
3
0
Pa
CO
Tn3
H
H
—
H
117
Ir
3
0
Pa
CR2
Ph
H
H
—
H
H
H
118
Ir
3
0
Pa
CR2
Tn1
H
H
—
H
H
H
119
Ir
3
0
Pa
CR2
Tn2
H
H
—
H
H
H
120
Ir
3
0
Pa
CR2
Tn3
H
H
—
H
H
H
121
Ir
3
0
Pr2
O
Ph
H
H
H
H
122
Ir
3
0
Pr2
O
Tn1
H
H
H
H
123
Ir
3
0
Pr2
O
Tn2
H
H
H
H
124
Ir
3
0
Pr2
O
Tn3
H
H
H
H
125
Ir
3
0
Pr2
S
Ph
H
H
H
H
126
Ir
3
0
Pr2
S
Tn1
H
H
H
H
127
Ir
3
0
Pr2
S
Tn2
H
H
H
H
128
Ir
3
0
Pr2
S
Tn3
H
H
H
H
129
Ir
3
0
Pr2
NR
Ph
H
H
H
H
H
130
Ir
3
0
Pr2
NR
Tn1
H
H
H
H
H
131
Ir
3
0
Pr2
NR
Tn2
H
H
H
H
H
132
Ir
3
0
Pr2
NR
Tn3
H
H
H
H
H
133
Ir
3
0
Pr2
CO
Ph
H
H
H
H
134
Ir
3
0
Pr2
CO
Tn1
H
H
H
H
135
Ir
3
0
Pr2
CO
Tn2
H
H
H
H
136
Ir
3
0
Pr2
CO
Tn3
H
H
H
H
137
Ir
3
0
Pr2
CR2
Ph
H
H
H
H
H
138
Ir
3
0
Pr2
CR2
Tn1
H
H
H
H
H
139
Ir
3
0
Pr2
CR2
Tn2
H
H
H
H
H
140
Ir
3
0
Pr2
CR2
Tn3
H
H
H
H
H
141
Ir
3
0
Pz
O
Ph
H
H
H
H
142
Ir
3
0
Pz
O
Tn1
H
H
H
H
143
Ir
3
0
Pz
O
Tn2
H
H
H
H
144
Ir
3
0
Pz
O
Tn3
H
H
H
H
145
Ir
3
0
Pz
S
Ph
H
H
H
H
146
Ir
3
0
Pz
S
Tn1
H
H
H
H
147
Ir
3
0
Pz
S
Tn2
H
H
H
H
148
Ir
3
0
Pz
S
Tn3
H
H
H
H
149
Ir
3
0
Pz
NR
Ph
H
H
H
H
H
150
Ir
3
0
Pz
NR
Tn1
H
H
H
H
H
151
Ir
3
0
Pz
NR
Tn2
H
H
H
H
H
152
Ir
3
0
Pz
NR
Tn3
H
H
H
H
H
153
Ir
3
0
Pz
CO
Ph
H
H
H
H
154
Ir
3
0
Pz
CO
Tn1
H
H
H
H
155
Ir
3
0
Pz
CO
Tn2
H
H
H
H
156
Ir
3
0
Pz
CO
Tn3
H
H
H
H
157
Ir
3
0
Pz
CR2
Ph
H
H
H
H
H
H
158
Ir
3
0
Pz
CR2
Tn1
H
H
H
H
H
H
159
Ir
3
0
Pz
CR2
Tn2
H
H
H
H
H
H
160
Ir
3
0
Pz
CR2
Tn3
H
H
H
H
H
H
161
Ir
3
0
Pr
NR
Ph
H
H
H
H
phenyl
162
Ir
3
0
Pr
NR
Ph
H
H
H
H
naphthyl
163
Ir
3
0
Pr
NR
Ph
H
H
H
H
—CH3
164
Ir
3
0
Pr
NR
Ph
H
H
H
H
—C4H9
165
Ir
3
0
Pr
CR2
Qn1
H
H
H
H
—CH3
—CH3
166
Ir
3
0
Pr
CR2
Qn2
H
H
H
H
—C4H9
—C4H9
167
Ir
3
0
Pr
CR2
Qx
H
H
H
H
H
—CH3
168
Ir
3
0
Pr
CR2
Qz1
—
H
H
H
H
—C4H9
169
Ir
3
0
Pr
CR2
Ph
H
H
H
CF3
H
170
Ir
3
0
Pr
CR2
Ph
H
CF3
H
H
H
171
Ir
3
0
Pr
CR2
Ph
H
H
H
CH3
H
172
Ir
3
0
Pr
CR2
Ph
H
H
CH3
H
H
173
Ir
3
0
Pr
CR2
Qn1
H
H
H
OCF3
H
H
174
Ir
3
0
Pr
CR2
Qn2
H
OC2H5
H
H
H
H
175
Ir
3
0
Pr
CR2
Qx
H
H
H
OC2H5
H
H
176
Ir
3
0
Pr
CR2
Qz1
—
H
COOC2H5
H
H
H
177
Ir
3
0
Pr
O
Ph
H
H
H
CF3
—
178
Ir
3
0
Pr
O
Ph
H
CF3
H
H
—
179
Ir
3
0
Pr
NR2
Ph
H
H
H
CH3
H
180
Ir
3
0
Pr
NR2
Ph
H
H
CH3
H
H
181
Ir
3
0
Pr
NR2
Qn1
H
H
H
OCF3
H
—
182
Ir
3
0
Pr
CO
Qn2
H
OC2H5
H
H
—
—
183
Ir
3
0
Pr
CO
Qx
H
H
H
OC2H5
—
—
184
Ir
3
0
Pr
CO
Qz1
—
H
COOC2H5
H
—
—
185
Rh
3
0
Pr
CO
Ph
H
H
H
H
186
Rh
3
0
Pr
CO
Tn1
H
H
H
H
187
Rh
3
0
Pr
CR2
Tn2
H
H
H
H
H
H
188
Rh
3
0
Pr
CR2
Tn3
H
H
H
H
H
H
189
Rh
3
0
Pr
O
Qn1
H
H
H
H
190
Rh
3
0
Pr
O
Qn2
H
H
H
H
191
Rh
3
0
Pr
S
Qx
H
H
H
H
192
Rh
3
0
Pr
S
Qz1
—
H
H
H
193
Rh
3
0
Pr
NR
Qz2
H
—
H
H
H
194
Rh
3
0
Pr
NR
Cnl
H
H
H
H
H
195
Pd
2
0
Pr
CO
Ph
H
H
H
H
196
Pd
2
0
Pr
CO
Tn1
H
H
H
H
197
Pd
2
0
Pr
CR2
Tn2
H
H
H
H
H
H
198
Pd
2
0
Pr
CR2
Tn3
H
H
H
H
H
H
199
Pd
2
0
Pr
O
Qn1
H
H
H
H
200
Pd
2
0
Pr
O
Qn2
H
H
H
H
201
Pd
2
0
Pr
S
Qx
H
H
H
H
202
Pd
2
0
Pr
S
Qz1
—
H
H
H
203
Pd
2
0
Pr
NR
Qz2
H
—
H
H
H
204
Pd
2
0
Pr
NR
Cn1
—
H
H
H
H
205
Pt
2
0
Pr
CO
Ph
H
H
H
H
206
Pt
2
0
Pr
CO
Tn1
H
H
H
H
207
Pt
2
0
Pr
CR2
Tn2
H
H
H
H
H
H
208
Pt
2
0
Pr
CR2
Tn3
H
H
H
H
H
H
209
Pt
2
0
Pr
O
Qn1
H
H
H
H
210
Pt
2
0
Pr
O
Qn2
H
H
H
H
211
Pt
2
0
Pr
S
Qx
H
H
H
H
212
Pt
2
0
Pr
S
Qz1
—
H
H
H
213
Pt
2
0
Pr
NR
Qz2
H
—
H
H
H
214
Pt
3
0
Pr
NR
Cn1
—
H
H
H
H
215
Ir
2
0
Pr
CR2
Ph
H
H
H
H
H
H
CH3—CO—
CH—CO—
CH3
216
Ir
2
0
Pr
CR2
Tn1
H
H
H
H
H
H
CH3—CO—
CH—CO—
CH3
217
Ir
2
0
Pr
CO
Tn2
H
H
H
H
CH3—CO—
CH—CO—
CH3
218
Ir
2
0
Pr
CO
Tn3
H
H
H
H
CH3—CO—
CH—CO—
CH3
L
No
M
m
n
CyN1orCyN2
CyC1orCyC2
R1
R2
R3
R4
R5
R6
CyN3
CyC3
R1
L′R2
R3
R4
219
Ir
2
1
Pr
O
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
220
Ir
2
1
Pr
O
Ph
H
H
H
H
Pr
Ph
H
H
H
H
221
Ir
2
1
Pr
O
Ph
H
H
H
H
Py1
Ph
H
H
H
—
222
Ir
2
1
Pr
O
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
223
Ir
2
1
Pr
O
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
224
Ir
2
1
Pr
O
Ph
H
H
H
H
Py1
Ph
H
H
H
—
225
Ir
2
1
Pr
CO
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
226
Ir
2
1
Pr
CO
Ph
H
H
H
H
Pr
Ph
H
H
H
H
227
Ir
2
1
Pr
CO
Ph
H
H
H
H
Py1
Ph
H
H
H
—
228
Ir
2
1
Pr
CO
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
229
Ir
2
1
Pr
CO
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
230
Ir
2
1
Pr
CO
Ph
H
H
H
H
Py1
Ph
H
H
H
—
231
Ir
2
1
Pr
NR
Ph
H
H
H
H
CH3
Pr
Tn1
H
H
H
H
232
Ir
2
1
Pr
NR
Ph
H
H
H
H
CH3
Pr
Ph
H
H
H
H
233
Ir
2
1
Pr
NR
Ph
H
H
H
H
CH3
Py1
Ph
H
H
H
—
234
Ir
2
1
Pr
NR
Ph
H
H
H
H
CH3
Pr
Ph
CF3
H
H
H
235
Ir
2
1
Pr
NR
Ph
H
H
H
H
CH3
Pr
Tn1
H
H
H
H
236
Ir
2
1
Pr
NR
Ph
H
H
H
H
CH3
Py1
Ph
H
H
H
—
237
Ir
2
1
Pr
NR
Tn1
H
H
H
H
C2H5
Pr
Tn1
H
H
H
H
238
Ir
2
1
Pr
NR
Tn1
H
H
H
H
C2H5
Pr
Ph
H
H
H
H
239
Ir
2
1
Pr
NR
Tn1
H
H
H
H
C2H5
Py1
Ph
H
H
H
—
240
Ir
2
1
Pr
NR
Qn1
H
H
H
H
C2H5
Pr
Ph
F
H
H
H
241
Ir
2
1
Pr
NR
Qn1
H
H
H
H
C2H5
Pr
Tn1
H
H
H
H
242
Ir
2
1
Pr
NR
Qn1
H
H
H
H
C2H5
Py1
Ph
H
H
H
—
243
Pt
1
1
Pr
O
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
244
Pt
1
1
Pr
O
Ph
H
H
H
H
Pr
Ph
H
H
H
H
245
Pt
1
1
Pr
O
Ph
H
H
H
H
Py1
Ph
H
H
H
—
246
Pt
1
1
Pr
O
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
247
Pt
1
1
Pr
O
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
248
Pt
1
1
Pr
O
Ph
H
H
H
H
Py1
Ph
H
H
H
—
249
Pt
1
1
Pr
CO
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
250
Pt
1
1
Pr
CO
Ph
H
H
H
H
Pr
Ph
H
H
H
H
251
Pt
1
1
Pr
CO
Ph
H
H
H
H
Py1
Ph
H
H
H
—
252
Pt
1
1
Pr
CO
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
253
Pt
1
1
Pr
CO
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
254
Pt
1
1
Pr
CO
Ph
H
H
H
H
Py1
Ph
H
H
H
—
255
Pt
1
1
Pr
NR
Ph
H
H
H
H
CH3
Pr
Tn1
H
H
H
H
256
Pt
1
1
Pr
NR
Ph
H
H
H
H
CH3
Pr
Ph
H
H
H
H
257
Pt
1
1
Pr
NR
Ph
H
H
H
H
CH3
Py1
Ph
H
H
H
—
258
Pt
1
1
Pr
NR
Ph
H
H
H
H
CH3
Pr
Ph
CF3
H
H
H
259
Pt
1
1
Pr
NR
Ph
H
H
H
H
CH3
Pr
Tn1
H
H
H
H
260
Pt
1
1
Pr
NR
Ph
H
H
H
H
CH3
Py1
Ph
H
H
H
—
261
Pt
1
1
Pr
NR
Tn1
H
H
H
H
C2H5
Pr
Tn1
H
H
H
H
262
Pt
1
1
Pr
NR
Tn1
H
H
H
H
C2H5
Pr
Ph
H
H
H
H
263
Pt
1
1
Pr
NR
Tn1
H
H
H
H
C2H5
Py1
Ph
H
H
H
—
264
Pt
1
1
Pr
NR
Qn1
H
H
H
H
C2H5
Pr
Ph
F
H
H
H
265
Pt
1
1
Pr
NR
Qn1
H
H
H
H
C2H5
Pr
Tn1
H
H
H
H
266
Pt
1
1
Pr
NR
Qn1
H
H
H
H
C2H5
Py1
Ph
H
H
H
—
267
Ir
2
1
Pr
—
Ph
F
H
H
H
Pr
Ph
CH3
H
H
H
268
Ir
2
1
Pr
—
Ph
F
F
H
H
Pr
Ph
H
H
H
H
269
Ir
2
1
Pr
—
Ph
F
H
H
H
Pr
Ph
CF3
H
H
H
270
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
271
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Tn2
H
H
H
H
272
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Tn3
H
H
H
H
273
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Np
H
H
H
H
274
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Qn1
H
H
H
H
275
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Qn2
H
H
H
H
276
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Qx
H
H
H
H
277
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Qz1
—
H
H
H
278
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Qz2
H
—
H
H
279
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Cn1
—
H
H
H
280
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Cn2
H
—
H
H
281
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Pz
—
—
H
H
282
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
283
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
Ph
H
CF3
H
H
284
Ir
2
1
Pr
—
Ph
H
H
H
H
Pr
tn3
H
H
H
CF3
285
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
286
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Tn2
H
H
H
H
287
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Tn3
H
H
H
H
288
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Np
H
H
H
H
289
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Qn1
H
H
H
H
290
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Qn2
H
H
H
H
291
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Qx
H
H
H
H
292
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Qx1
—
H
H
H
293
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Qx2
H
—
H
H
294
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Cn1
—
H
H
H
295
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Cn2
H
—
H
H
296
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Pz
—
—
H
H
297
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
298
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
Ph
H
CF3
H
H
299
Ir
1
2
Pr
—
Ph
H
H
H
H
Pr
tn3
H
H
H
CF3
300
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Tn3
H
H
H
H
301
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Np
H
H
H
H
302
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Qn1
H
H
H
H
303
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Qn2
H
H
H
H
304
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Qx
H
H
H
H
305
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Qz1
—
H
H
H
306
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Qz2
H
—
H
H
307
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Cn1
—
H
H
H
308
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Cn2
H
—
H
H
309
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Pz
—
—
H
H
310
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Ph
CH3
H
H
H
311
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
Ph
H
CF3
H
H
312
Ir
2
1
Pr
—
Tn1
H
H
H
H
Pr
tn3
H
H
H
CF3
313
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Tn3
H
H
H
H
314
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Np
H
H
H
H
315
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Qn1
H
H
H
H
316
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Qn2
H
H
H
H
317
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Qx
H
H
H
H
318
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Qz1
—
H
H
H
319
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Qz2
H
—
H
H
320
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Cn1
—
H
H
H
321
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Cn2
H
—
H
H
322
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Pz
—
—
H
H
323
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Ph
CH3
H
H
H
324
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
Ph
H
CF3
H
H
325
Ir
1
2
Pr
—
Tn1
H
H
H
H
Pr
tn3
H
H
H
CF3
326
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
327
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
328
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Tn3
H
H
H
H
329
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Np
H
H
H
H
330
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Qn1
H
H
H
H
331
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Qn2
H
H
H
H
332
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Qx
H
H
H
H
333
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Qz1
—
H
H
H
334
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Qz2
H
—
H
H
335
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Cn1
—
H
H
H
336
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Cn2
H
—
H
H
337
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Pz
—
—
H
H
338
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
339
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
Ph
H
CF3
H
H
340
Ir
2
1
Py1
—
Ph
H
H
H
H
Pr
tn3
H
H
H
CF3
341
Ir
1
2
Py1
—
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
342
Ir
1
2
Py1
—
Ph
H
H
H
H
Pr
Tn2
H
H
H
H
343
Ir
1
2
Py1
—
Ph
H
H
H
H
Pr
Tn3
H
H
H
H
344
Ir
1
2
Py1
—
Ph
H
H
H
H
Pr
Np
H
H
H
H
345
Ir
1
2
Py1
—
Ph
H
H
H
H
Pr
Qn1
H
H
H
H
346
Ir
1
2
Py1
—
Ph
H
H
H
H
Pr
Qn2
H
H
H
H
347
Ir
1
2
Py1
—
Ph
H
H
H
H
Pr
Qx
H
H
H
H
348
Ir
1
2
Py1
—
Pr
H
H
H
H
Pr
Qz1
—
H
H
H
349
Ir
1
2
Py1
—
Pr
H
H
H
H
Pr
Qz2
H
—
H
H
350
Ir
1
2
Py1
—
Pr
H
H
H
H
Pr
Cn1
—
H
H
H
351
Ir
1
2
Py1
—
Pr
H
H
H
H
Pr
Cn2
H
—
H
H
352
Ir
1
2
Py1
—
Pr
H
H
H
H
Pr
Pz
—
—
H
H
353
Ir
1
2
Py1
—
Pr
H
H
H
H
Pr
Ph
CH3
H
H
H
354
Ir
1
2
Py1
—
Pr
H
H
H
H
Pr
Ph
H
CF3
H
H
355
Ir
1
2
Py1
—
Pr
H
H
H
H
Pr
tn3
H
H
H
CF3
356
Ir
2
1
Py1
—
Ph
H
H
H
H
Pz
Tn1
H
H
H
H
357
Ir
2
1
Py1
—
Ph
H
H
H
H
Pz
Tn2
H
H
H
H
358
Ir
2
1
Py1
—
Ph
H
H
H
H
Pz
Tn3
H
H
H
H
359
Ir
2
1
Py1
—
Ph
H
H
H
H
Pa
Np
H
H
—
H
360
Ir
2
1
Py1
—
Ph
H
H
H
H
Pa
Qn1
H
H
—
H
361
Ir
2
1
Py1
—
Ph
H
H
H
H
Pa
Qn2
H
H
—
H
362
Ir
2
1
Py1
—
Ph
H
H
H
H
Py2
Qx
H
H
H
H
363
Ir
2
1
Py1
—
Ph
H
H
H
H
Py2
Qz1
H
—
H
H
364
Ir
2
1
Py1
—
Ph
H
H
H
H
Py2
Qz2
H
—
H
H
365
Ir
2
1
Py1
—
Ph
H
H
H
H
Py1
Cn1
—
H
H
H
366
Ir
2
1
Py1
—
Ph
H
H
H
H
Py1
Cn2
H
—
H
H
367
Ir
2
1
Py1
—
Ph
H
H
H
H
Py1
Pz
—
—
H
H
368
Ir
2
1
Py1
—
Ph
H
H
H
H
Py2
Ph
CH3
H
H
H
369
Ir
2
1
Py1
—
Ph
H
H
H
H
Py2
Ph
H
CF3
H
H
370
Ir
2
1
Py1
—
Ph
H
H
H
H
Py2
tn3
H
H
H
CF3
371
Ir
2
1
Pr
—
Ph
H
H
H
H
formula 11
372
Ir
2
1
Pr
—
Ph
H
H
H
H
formula 12
373
Ir
2
1
Pr
—
Ph
H
H
H
H
formula 13
374
Ir
2
1
Pr
—
Ph
H
H
H
H
formula 14
375
Ir
2
1
Pr
—
Tn1
H
H
H
H
formula 11
376
Ir
2
1
Pr
—
Tn1
H
H
H
H
formula 12
377
Ir
2
1
Pr
—
Tn1
H
H
H
H
formula 13
378
Ir
2
1
Pr
—
Tn1
H
H
H
H
formula 14
379
Ir
2
1
Pr
—
Tn3
H
H
H
H
formula 11
380
Ir
2
1
Pr
—
Tn3
H
H
H
H
formula 12
381
Ir
2
1
Pr
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H
H
H
H
573
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Tn3
H
H
H
H
574
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Np
H
H
H
H
575
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Qn1
H
H
H
H
576
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Qn2
H
H
H
H
577
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Qx
H
H
H
H
578
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Qz1
—
H
H
H
579
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Qz2
H
—
H
H
580
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Cn1
—
H
H
H
581
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Cn2
H
—
H
H
582
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Pz
—
—
H
H
583
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
584
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
Ph
H
CF3
H
H
585
Pt
1
1
Pr
—
Ph
H
H
H
H
Pr
tn3
H
H
H
CF3
586
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Tn3
H
H
H
H
587
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Np
H
H
H
H
588
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qn1
H
H
H
H
589
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qn2
H
H
H
H
590
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qx
H
H
H
H
591
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qz1
—
H
H
H
592
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qz2
H
—
H
H
593
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Cn1
—
H
H
H
594
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Cn2
H
—
H
H
595
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Pz
—
—
H
H
596
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Ph
CH3
H
H
H
597
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
Ph
H
CF3
H
H
598
Pt
1
1
Pr
—
Tn1
H
H
H
H
Pr
tn3
H
H
H
CF3
599
Pt
1
1
Pr
—
Ph
H
H
H
H
formula 11
600
Pt
1
1
Pr
—
Ph
H
H
H
H
formula 12
601
Pt
1
1
Pr
—
Ph
H
H
H
H
formula 13
602
Pt
1
1
Pr
—
Ph
H
H
H
H
formula 14
603
Pt
1
1
Pr
—
Tn1
H
H
H
H
formula 11
604
Pt
1
1
Pr
—
Tn1
H
H
H
H
formula 12
605
Pt
1
1
Pr
—
Tn1
H
H
H
H
formula 13
606
Pt
1
1
Pr
—
Tn1
H
H
H
H
formula 14
607
Pt
1
1
Pr
—
Tn3
H
H
H
H
formula 11
608
Pt
1
1
Pr
—
Tn3
H
H
H
H
formula 12
609
Pt
1
1
Pr
—
Tn3
H
H
H
H
formula 13
610
Pt
1
1
Pr
—
Tn3
H
H
H
H
formula 14
611
Pt
1
1
Pr
—
Np
H
H
H
H
formula 11
612
Pt
1
1
Pr
—
Np
H
H
H
H
formula 12
613
Pt
1
1
Pr
—
Np
H
H
H
H
formula 13
614
Pt
1
1
Pr
—
Np
H
H
H
H
formula 14
615
Pt
1
1
Pr
—
Qn2
H
H
H
H
formula 11
616
Pt
1
1
Pr
—
Qn2
H
H
H
H
formula 12
617
Pt
1
1
Pr
—
Qn2
H
H
H
H
formula 13
618
Pt
1
1
Pr
—
Qn2
H
H
H
H
formula 14
619
Pt
1
1
Py1
—
Ph
H
H
H
—
formula 11
620
Pt
1
1
Py1
—
Ph
H
H
H
—
formula 12
621
Pt
1
1
Py1
—
Ph
H
H
H
—
formula 13
622
Pt
1
1
Py1
—
Ph
H
H
H
—
formula 14
623
Pt
1
1
Py2
—
Ph
H
H
H
H
formula 11
624
Pt
1
1
Py2
—
Ph
H
H
H
H
formula 12
625
Pt
1
1
Py2
—
Ph
H
H
H
H
formula 13
626
Pt
1
1
Py2
—
Ph
H
H
H
H
formula 14
627
Pt
1
1
Pz
—
Ph
H
H
H
H
formula 11
628
Pt
1
1
Pz
—
Ph
H
H
H
H
formula 12
629
Pt
1
1
Pz
—
Ph
H
H
H
H
formula 13
630
Pt
1
1
Pz
—
Ph
H
H
H
H
formula 14
631
Pt
1
1
Pa
—
Ph
H
H
H
—
formula 11
632
Pt
1
1
Pa
—
Ph
H
H
H
—
formula 12
633
Pt
1
1
Pa
—
Ph
H
H
H
—
formula 13
634
Pt
1
1
Pa
—
Ph
H
H
H
—
formula 14
635
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Tn1
H
H
H
H
636
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Tn2
H
H
H
H
637
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Tn3
H
H
H
H
638
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Np
H
H
H
H
639
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Qn1
H
H
H
H
640
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Qn2
H
H
H
H
641
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Qx
H
H
H
H
642
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Qz1
—
H
H
H
643
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Oz2
H
—
H
H
644
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Cn1
—
H
H
H
645
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Cn2
H
—
H
H
646
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Pz
—
—
H
H
647
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Ph
CH3
H
H
H
648
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
Ph
H
CF3
H
H
649
Pd
1
1
Pr
—
Ph
H
H
H
H
Pr
tn3
H
H
H
CF3
650
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Tn3
H
H
H
H
651
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Np
H
H
H
H
652
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qn1
H
H
H
H
653
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qn2
H
H
H
H
654
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qx
H
H
H
H
655
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qz1
—
H
H
H
656
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Qz2
H
—
H
H
657
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Cn1
—
H
H
H
658
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Cn2
H
—
H
H
659
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Pz
—
—
H
H
660
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Ph
CH3
H
H
H
661
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
Ph
H
CF3
H
H
662
Pd
1
1
Pr
—
Tn1
H
H
H
H
Pr
tn3
H
H
H
CF3
663
Pd
1
1
Pr
—
Ph
H
H
H
H
formula 11
664
Pd
1
1
Pr
—
Ph
H
H
H
H
formula 12
665
Pd
1
1
Pr
—
Ph
H
H
H
H
formula 13
666
Pd
1
1
Pr
—
Ph
H
H
H
H
formula 14
667
Pd
1
1
Pr
—
Tn1
H
H
H
H
formula 11
668
Pd
1
1
Pr
—
Tn1
H
H
H
H
formula 12
669
Pd
1
1
Pr
—
Tn1
H
H
H
H
formula 13
670
Pd
1
1
Pr
—
Tn1
H
H
H
H
formula 14
671
Pd
1
1
Pr
—
Tn3
H
H
H
H
formula 11
672
Pd
1
1
Pr
—
Tn3
H
H
H
H
formula 12
673
Pd
1
1
Pr
—
Tn3
H
H
H
H
formula 13
674
Pd
1
1
Pr
—
Tn3
H
H
H
H
formula 14
675
Pd
1
1
Pr
—
Np
H
H
H
H
formula 11
676
Pd
1
1
Pr
—
Np
H
H
H
H
formula 12
677
Pd
1
1
Pr
—
Np
H
H
H
H
formula 13
678
Pd
1
1
Pr
—
Np
H
H
H
H
formula 14
679
Pd
1
1
Pr
—
Qn2
H
H
H
H
formula 11
680
Pd
1
1
Pr
—
Qn2
H
H
H
H
formula 12
681
Pd
1
1
Pr
—
Qn2
H
H
H
H
formula 13
682
Pd
1
1
Pr
—
Qn2
H
H
H
H
formula 14
683
Pd
1
1
Py1
—
Ph
H
H
H
—
formula 11
684
Pd
1
1
Py1
—
Ph
H
H
H
—
formula 12
685
Pd
1
1
Py1
—
Ph
H
H
H
—
formula 13
686
Pd
1
1
Py1
—
Ph
H
H
H
—
formula 14
687
Pd
1
1
Py2
—
Ph
H
H
H
H
formula 11
688
Pd
1
1
Py2
—
Ph
H
H
H
H
formula 12
689
Pd
1
1
Py2
—
Ph
H
H
H
H
formula 13
690
Pd
1
1
Py2
—
Ph
H
H
H
H
formula 14
691
Pd
1
1
Pz
—
Ph
H
H
H
H
formula 11
692
Pd
1
1
Pz
—
Ph
H
H
H
H
formula 12
693
Pd
1
1
Pz
—
Ph
H
H
H
H
formula 13
694
Pd
1
1
Pz
—
Ph
H
H
H
H
formula 14
695
Pd
1
1
Pa
—
Ph
H
H
—
H
formula 11
696
Pd
1
1
Pa
—
Ph
H
H
—
H
formula 12
697
Pd
1
1
Pa
—
Ph
H
H
—
H
formula 13
698
Pd
1
1
Pa
—
Ph
H
H
—
H
formula 14
L
No
M
m
n
CyN1
CyC1
R1
R2
R3
R4
R5
R6
L′
699
Ir
2
0
Pr
CR2
Ph
H
H
H
H
F
F
CH3—CO—CH—CO—CH3
700
Ir
3
0
Pr
CR2
Ph
H
H
H
H
F
F
Hereinbelow, the present invention will be described more specifically based on Examples with reference to the drawing.
EXAMPLES 1 AND 2
In these examples, the following metal coordination compounds of formula (1) (Ex. Comp. Nos. 37 and 1) were used in respective luminescence layers for Examples 1 and 2 respectively.
Ex. Comp. No. 37
Ex. Comp. No. 1
Each of organic luminescence devices having a structure including four organic (compound) layers (luminescence function layers) shown in FIG. 1C were prepared in the following manner.
On a 1.1 mm-thick glass substrate (transparent substrate 15 ), a 100 nm-thick film (transparent electrode 14 ) of ITO (indium tin oxide) was formed by sputtering, followed by patterning to have an (opposing) electrode area of 3 mm 2 .
On the ITO-formed substrate, four organic layers and two metal electrode layers shown below were successively formed by vacuum (vapor) deposition using resistance heating in a vacuum chamber (10 −4 Pa).
Organic layer 1 (hole transport layer 13 ) (50 nm): α-NPD
Organic layer 2 (luminescence layer 12 ) (40 nm): CBP: metal coordination compound of formula (1) (93:7 by weight) (co-vacuum deposition)
Organic layer 3 (exciton diffusion prevention layer 17 ) (20 nm): BCP
Organic layer 4 (electron transport layer 16 ) (40 nm): Alq3
Metal electrode layer 1 (metal electrode 11 ) (15 nm): Al—Li alloy (Li=1.8 wt. %)
Metal electrode layer 2 (metal electrode 11 ) (100 nm): Al
EL characteristics of the luminescence devices using the metal coordination compounds of formula (1) (Ex. Comp. Nos. 37 and 1) were measured by using a microammeter (“Model 4140B”, mfd. by Hewlett-Packard Co.) for a current density under application of a voltage of 20 volts using a luminance meter (“Model BM7”, mfd. by Topcon K.K.) for a luminescence efficiency (luminescence luminance). Further, both the above-prepared luminescence devices showed a good rectification characteristic.
The results are shown below.
Ex. No.
Ex. Comp. No.
Luminance (cd/m 2 )
1
37
50
2
1
25
Each of luminescence states of the organic luminescence devices was similar to that based on photoluminescence (luminescence center wavelength) in the case where each of the luminescence materials (Ex. Comp. Nos. 37 and Ex. Comp. No. 1 as luminescence sources in these examples) was dissolved in toluene.
Accordingly, luminescence from these organic luminescence devices was found to be resulting from the corresponding luminescence material.
EXAMPLE 3
A simple matrix-type organic EL device shown in FIG. 2 was prepared in the following manner.
On a 1.1 mm-thick glass substrate 21 (75×75 mm), a ca. 100 nm-thick transparent electrode 22 of ITO (as an anode) was formed by sputtering, followed by patterning in a stripe form comprising 100 lines (each having a width of 100 μm and a spacing of 40 μm).
On the ITO electrode 22 , an organic lamination layer 23 including four organic layers was formed in the same manner as in Example 1.
Then, on the organic lamination layer 23 , a metal electrode comprising a 10 nm-thick Al—Li alloy layer (Li: 1.3 wt. %) and a 150 nm-thick Al layer (disposed on the Al—Li alloy layer) was formed by vacuum deposition (2.7×10 −3 Pa (=2×10 −5 Torr)) with a mask, followed by patterning in a stripe form comprising 100 lines (each having a width of 100 μm and a spacing of 40 μm) arranged to intersect the ITO stripe electrode lines at right angles, thus forming an organic EL device having a matrix of pixels (100×100 pixels).
The thus-prepared organic EL device was placed in a glove box and driven in a simple matrix manner (frame frequency: 30 Hz,interlace scanning) by applying a driving waveform (drive voltage: 15 to 23 volts, scanning signal voltage: 19 volts, data signal voltage: ±4 volts) as shown in FIG. 3 .
As a result, a smooth motion picture display by the organic EL device was confirmed.
EXAMPLE 4
An organic EL device was prepared in the same manner as in Example 1 except that the metal coordination compound (Ex. Comp. No. 37) was changed to a metal coordination compound of the formula 41 (specifically shown hereinabove).
When the EL device was supplied with a voltage of 20 volts, stable and high-efficiency yellowish green luminescence resulting from the thienylpyridine ligand of the metal coordination compound of the formula 41 was confirmed. The luminescence was stable even when the EL device was continuously driven for 100 hours.
EXAMPLE 5
An organic EL device was prepared in the same manner as in Example 1 except that the metal coordination compound (Ex. Comp. No. 37) was changed to a metal coordination compound of the formula 44 (specifically shown hereinabove).
When the EL device was supplied with a voltage of 20 volts, stable and high-efficiency reddish orange luminescence resulting from the metal coordination compound of the formula 44 was confirmed. The luminescence was stable even when the EL device was continuously driven for 100 hours.
EXAMPLE 6
An organic EL device was prepared in the same manner as in Example 1 except that the metal coordination compound (Ex. Comp. No. 37) was changed to a metal coordination compound of the formula 46 (specifically shown hereinabove).
When the EL device was supplied with a voltage of 20 volts, stable and high-efficiency reddish orange luminescence resulting from the metal coordination compound of the formula 46 was confirmed. The luminescence was stable even when the EL device was continuously driven for 100 hours.
EXAMPLE 7
An organic EL device was prepared in the same manner as in Example 1 except that the metal coordination compound (Ex. Comp. No. 37) was changed to a metal coordination compound of the formula 49 (specifically shown hereinabove).
When the EL device was supplied with a voltage of 20 volts, stable and high-efficiency reddish orange luminescence resulting from the metal coordination compound of the formula 49 was confirmed. The luminescence was stable even when the EL device was continuously driven for 100 hours.
EXAMPLE 8
An organic EL device was prepared in the same manner as in Example 1 except that the metal coordination compound (Ex. Comp. No. 37) was changed to a metal coordination compound of the formula 50 (specifically shown hereinabove).
When the EL device was supplied with a voltage of 20 volts, stable and high-efficiency reddish orange luminescence resulting from the metal coordination compound of the formula 50 was confirmed. The luminescence was stable even when the EL device was continuously driven for 100 hours.
EXAMPLE 9
An organic EL device was prepared in the same manner as in Example 1 except that the metal coordination compound (Ex. Comp. No. 37) was changed to a metal coordination compound of the formula 42 (specifically shown hereinabove).
When the EL device was supplied with a voltage of 20 volts, stable and high-efficiency green luminescence resulting from the metal coordination compound of the formula 42 was confirmed. The luminescence was stable even when the EL device was continuously driven for 100 hours.
In the above Examples 4–9, all the metal coordination compounds according to the present invention improved a luminescence efficiency by ca. 20% when compared with corresponding metal coordination compounds having a single luminescent ligand structure, respectively.
EXAMPLE 10
Ir-based metal coordination compounds of the formula (1) according to the present invention were basically synthesized through the following reaction schemes.
In the above, as a starting material, a commercially available Ir acetylacetonato complex or a commercially available hydrated Ir chloride was used. “L” denotes a ligand of an objective Ir complex.
In a specific synthesis example, a metal coordination compound (Ex. Comp. No. 49) was prepared in the following manner.
In a 100-four-necked flask, 50 ml of glycerol was placed and stirred for 2 hours at 130–140° C. while supplying nitrogen gas into glycerol, followed by cooling by standing to 100° C. At that temperature, 1.02 g (5.0 mM) of 2-benzylpyridine of formula A and 0.5 g (1.0 mM) of Ir(III) acetyl-acetonate (Ir(acac) 3 ) were added to the system, followed by stirring for 7 hours at ca. 210° C. in a nitrogen gas stream atmosphere.
The reaction mixture was cooled to room temperature and poured into 300 ml of 1N-hydrochloric acid. The resultant precipitate was recovered by filtration and washed with water, followed by purification by silica gel column chromatography (eluent: chloroform) to obtain 0.11 g of a black solid metal coordination compound (Ex. Comp. No. 49 of formula B) (Yield: 16%).
The thus-prepared metal coordination compound was subjected to MALDI-TOF-MS (Matrix-assisted Laser Desorption Ionization mass spectroscopy), whereby M + (mass number of ionized objective product) of 697.2 (as a molecular weight) was confirmed.
When the metal coordination compound was dissolved in toluene and subjected to measurement of luminescence spectrum, the metal coordination compound provided a luminescence spectrum diagram including a maximum luminescence wavelength λmax of 463 nm as shown in FIG. 5 .
Further, when Ir(ppy) 3 described hereinabove was used as a standard compound exhibiting a phosphorescence yield φ (Ir(ppy) 3 ) of 1, the metal coordination compound (Ex. Comp. No. 49) exhibited a phosphorescence yield φ (unknown) of 0.6.
Herein, the phosphorescence yield φ (φ (unknown)) may be obtained according to the following equation:
ϕ ( unknown ) / ϕ ( Ir ( ppy ) 3 ) = [ Sem ( unknown ) / Iabs ( unknown ) ] / [ Sem ( Ir ( ppy ) 3 ) / Iabs ( Ir ( ppy ) 3 ) ] ,
wherein φ (unknown) represents a phosphorescence yield of an unknown (objective) compound, φ (Ir(ppy) 3 ) represents a phosphorescence yield of Ir(ppy) 3 (=1 in this case) Sem (unknown) represents an absorption coefficient of an unknown compound at its excitation wavelength, Iabs (unknown) represents an areal intensity of emission spectrum of the unknown compound excited at the excitation wavelength, Sem (Ir(ppy) 3 represents an absorption coefficient of Ir(ppy) 3 at its excitation wavelength, and Iabs (Ir(ppy) 3 ) represents an areal intensity of emission spectrum of Ir(ppy) 3 excited at the excitation wavelength.
EXAMPLE 11
In this example, the metal coordination compound (Ex. Comp. No. 49) prepared in Example 10 was mixed with polyvinyl carbazole (PVK) shown below in a weight ratio of 8:92 to obtain a luminescent material used for a luminescence layer.
An organic EL device was prepared in the following manner.
A 1.1 mm-thick glass substrate provided with a 70 nm-thick ITO electrode (as an anode electrode) was subjected to plasma-ozone washing.
On the thus-treated glass substrate, a solution of the above-prepared luminescent material (mixture of the metal coordination compound (Ex. Comp. No. 49) and PVK) in chloroform was spin-coated at 2000 ppm, followed by drying to obtain a luminescence layer having a thickness of 90±10 nm.
The thus-treated glass substrate was then placed in a vacuum deposition chamber. On the luminescence layer of the substrate, a 30 nm-thick Mg—Ag alloy layer and a 100 nm-thick Al layer (as a cathode electrode) were successively formed by vacuum deposition (at most 10 −4 Pa), thus preparing an organic EL device.
When a DC voltage of 8–12 volts was applied between the ITO electrode (anode) and the metal electrode (cathode), clear blue luminescence was confirmed.
Further, the luminescence material (mixture) after drying exhibited a maximum luminescence wavelength was 490 nm closer to that (473 nm) of the metal coordination compound (Ex. Comp. No. 49) in toluene solution used in Example 10. Accordingly, the luminescence in this example was resulting from the metal coordination compound (Ex. Comp. No. 49).
After the DC voltage application, an attenuation time for the blue luminescence was at least 0.3–0.5 sec. As a result, the blue luminescence in this example was supported to be phosphorescence attributable to the metal coordination compound (Ex. Comp. No. 49).
The blue luminescence state was stable even when the EL device was continuously driven for 12 hours.
EXAMPLES 12 AND 13
In these examples, metal coordination compound (of formulas 43 and 51 specifically shown above) were synthesized through the following steps 1) to 4).
Step 1) (Synthesis of 2-(pyridine-2-yl)benzo[b]-thiophene
In a 1 liter-three-necked flask, 26.6 g (168.5 mM) of 2-bromopyridine, 30.0 g (168.5 mM) of benzo[b]thiophene-2-boric acid, 170 ml of toluene, 85 ml of ethanol and 170 ml of 2M-sodium carbonate aqueous solution were placed, and to the mixture, under stirring in a nitrogen gas stream atmosphere, 6.18 g (5.35 mM)of tetrakis-(triphenylphosphin) palladium (O) was added, followed by refluxing under stirring for 5.5 hours in a nitrogen gas stream atmosphere.
After the reaction, the reaction mixture was cooled and subjected to extraction with cold water and toluene.
The organic layer was washed with water until the layer became neutral, followed by distilling-off of the solvent under reduced pressure to obtain a residue. The residue was purified by silica gel column chromatography (eluent: toluene/hexane=5/1) and then by alumina column chromatography (eluent: toluene) and was recrystallized from ethanol to obtain 12.6 g o 2-(pyridine-2-yl)benzo[b]thiophene (Yield: 35.4%).
Step 2) (Synthesis of tetrakis(2-benzo[b]-thiophene-2-yl)pyridine-C 3 ,N)(μ-dichloro)diiridium (III)
In a 500 ml-three-necked flask, 3.65 g (10.4 mM) of n-hydrated iridium (III) chloride (IrCl·nH 2 O), 4.82 g (22.8 mM) of 2-(benzo[b]thiophene-2-yl)pyridine, 150 ml of 2-ethoxy ethanol and 50 ml of water were placed and stirred for 0.5 hour at room temperature in an argon gas atmosphere. The mixture was then gradually heated and subjected to refluxing for ca. 24 hours under stirring.
After cooling, the reaction mixture was subjected to filtration, followed by washing with ethanol and acetone.
The resultant powder was dissolved in chloroform and subjected to extraction with water. The organic layer was dried with anhydrous magnesium sulfate, followed distilling-off of the solvent to obtain a residue. The residue was recrystallized from a mixture solvent (hexanemethylene chloride) to obtain 5.40 g of tetrakis(2-(benzo[b]thiophene-2-yl)pyridine-C 3 , N) (μ-dichloro)diiridium (III) (Yield: 80.1%).
Step 3) Synthesis of bis(2-(benzo[b]thiophene-2-yl)pyridine-C 3 ,N) (acetylacetonato)iridium (III)
In a 500 ml-three-necked flask, 2.2 g (1.70 mM) of tetrakis (2-(benzo[b]thiophene-2-yl) pyridine-C 3 ,N) (μ-dichloro)diiridium, 0.51 g (5.09 mM) of acetylacetone, 2.5 g of sodium carbonate and 150 ml of ethanol were placed and stirred for 1 hour in an argon gas stream atmosphere.
The mixture was then gradually heated and subjected to refluxing for 15 hours under stirring.
After the reaction, the reaction mixture was cooled. The resultant precipitate was recovered by filtration and washed with water and ethanol to obtain a residue. The residue was purified by silica gel column chromatography (eluent: chloroform) and recrystallized from ethanol to obtain 1.87 g of bis(2-(benzo[b]thiophene-2-yl)pyridine-C 3 ,N) (acetylacetonato)iridium (III) (Yield: 77.3%).
Step 4) (Synthesis of bis(2-(benzo[b]thiophene-2-yl)pyridine-C 3 ,N) (phenylpyridine-C 2 ,N) iridium (III) (metal coordination compound of formula 51) and bis(phenylpyridine-C 2 ,N) (2-(benzo[b]thiophene-2-yl)pyridine-C 3 ,N) iridium (III) (metal coordination compound of formula 43))
In a 100 ml-three-necked flask, 50 ml of glycerol was placed and air in the interior of the flask was aerated with argon gas. Under stirring, 0.7 g (1.00 mM) of bis(2-benzo[b]thiophene-2-yl) pyridine-C 3 ,N) (acetylacetonato)iridium (III) and 0.39 g (2.50 mM) of 2-phenylpyridine were added to the glycerol, followed by stirring for 10 hours at 200° C.
After the reaction, to the reaction mixture, 300 ml of 1N-hydrochloric acid was added, followed by filtration. The resultant residue was purified by silica gel column chromatography (eluent: chloroform) and then fractionation by high-performance liquid chromatography to obtain 108 mg of bis(2-(benzo[b]thiophene-2-yl)pyridine-C 3 ,N) (phenylpyridine-C 2 ,N)iridium (III) (metal coordination compound of formula 51) and 35 mg of bis(phenylpyridine-C 2 ,N) (2-(benzo[b]thiophene-2-yl)pyridine-C 3 ,N) iridium (III) (metal coordination compound of formula 43)).
The thus-prepared metal coordination compounds (of formulas 51 and 43) were subjected to MALDI-TOF-MS, respectively, whereby M + of 767.1 for the metal coordination compound of formula 51 and M + of 711.1 for the metal coordination compound of formula 43 were confirmed, respectively.
When each of the metal coordination compounds of formulas 51 and 43 was dissolved in toluene and are subjected to measurement of luminescence spectrum, both the metal coordination compounds of formulas 51 and 43 exhibited a maximum luminescence wavelength λmax of 598 nm, thus confirming that the luminescence was attributable to the benzothienyl ligand.
Further, when Ir(ppy) 3 described hereinabove was used as a standard compound exhibiting a phosphorescence yield φ of 1, the metal coordination compound of formula 51 exhibited a phosphorescence yield φ of 0.2 and the metal coordination compound of formula 43 exhibited a phosphorescence yield φ of 0.3.
In order to confirm that the luminescence was phosphorescence, each of the metal coordination compounds of formulas 51 and 43 was dissolved in chloroform to prepare a first solution and a second solution. Each first solution was subjected to aeration with oxygen gas and each second solution was subjected to aeration with nitrogen gas.
When each of the thus-prepared first and second solutions were subjected to light irradiation, the oxygen-aerated solution exhibited substantially no phosphorescence but the nitrogen-aerated solution exhibited phosphorescence. As a result, these metal coordination compounds of formulas 51 and 43 were found to be phosphorescent metal coordination compounds.
The metal coordination compounds of formulas 51 and 43 were then subjected to measurement of luminescence life (time) in the following manner.
Each of the metal coordination compounds of formulas 51 and 43 was dissolved in chloroform and was spin-coated on a quartz substrate to form a ca. 0.1 μm-thick metal coordination compound layer.
By using a luminescence life-measuring apparatus (available from Hamamatsu Photonics K.K.), the above-prepared metal coordination compound layer formed on the substrate was subjected to pulse irradiation with nitrogen laser light (excitation wavelength: 337 nm) at room temperature to measure an attenuation time immediately after the excitation laser pulse irradiation.
A luminescence intensity I after a lapse of t (sec) is defined as the following equation:
I=I 0 exp(− t/τ ),
wherein I 0 represents an initial luminescence intensity and τ (μsec) represents a luminescence life (time).
As a result, both the metal coordination compounds of formulas 51 and 43 showed a shorter luminescence life of at most 10 μsec.
Accordingly, the metal coordination compound of the present invention is expected to provide an organic EL device using the metal coordination compound with a good stability since the metal coordination compound exhibits phosphorescent luminescence and a shorter phosphorescence life (time).
EXAMPLES 14 AND 15
Two organic EL devices using the metal coordination compound of formulas 51 and 43 prepared in Examples 12 and 13 were prepared in these examples.
Each of the organic luminescence devices had a structure including four organic (compound) layers (luminescence function layers) shown in FIG. 1C and was prepared in the following manner.
On a 1.1 mm-thick glass substrate (transparent substrate 15 ), a 100 nm-thick film (transparent electrode 14 ) of ITO (indium tin oxide) was formed by sputtering, followed by patterning to have an (opposing) electrode area of 3 mm 2 .
On the ITO-formed substrate, four organic layers and two metal electrode layers shown below were successively formed by vacuum (vapor) deposition using resistance heating in a vacuum chamber (10 −4 Pa).
Organic layer 1 (hole transport layer 13 ) (50 nm): α-NPD
Organic layer 2 (luminescence layer 12 ) (40 nm): CBP: metal coordination compound of formula (1) (93:7 by weight) (co-vacuum deposition)
Organic layer 3 (exciton diffusion prevention layer 17 ) (20 nm): BCP
Organic layer 4 (electron transport layer 16 ) (40 nm): Alq3
Metal electrode layer 1 (metal electrode 11 ) (15 nm): Al—Li alloy (Li=1.8 wt. %)
Metal electrode layer 2 (metal electrode 11 ) (100 nm): Al
EL characteristics of the luminescence devices using the metal coordination compounds of formulas 51 and 43 were measured by using a microammeter (“Model 4140B”, mfd. by Hewlett-Packard Co.) for a current density under application of a voltage of 8 volts (current-voltage characteristic), using a spectrophotofluoro-meter (“Model SR1”, mfd. by Topcon K.K.) for a maximum luminescence wavelength λmax, and using a luminance meter (“Model BM7”, mfd. by Topcon K.K.) for a luminescence efficiency. Further, both the above-prepared luminescence devices showed a good rectification characteristic.
The results are shown below.
Ex. No.
Formula
λmax (nm)
Luminance (cd/m 2 )
14
51
598
1.0
15
43
597
2.1
Each of luminescence states of the organic EL devices was similar to that based on photoluminescence in the case where each of the luminescence materials was dissolved in toluene.
Accordingly, luminescence from these organic EL devices was found to be resulting from the respective metal coordination compounds of formulas 51 and 43.
Further, as apparent from the above results, the metal coordination compound of formula 43 effectively improved the luminescence efficiency when compared with the metal coordination compound of formula 51.
In these metal coordination compounds of formulas 43 and 51, the luminescent ligand was the benzothienylpyridine ligand and thus the luminescence efficiency was found to be dependent upon the number of the benzothienylpyridine ligand.
According to these examples (Examples 14 and 15), it was confirmed that a lesser number of the benzothienylpyridine ligand (constituting the metal coordination compound of formula 43) as the luminescent ligand was more effective in improving the luminescence efficiency.
As described hereinabove, according to the present invention, it is possible to provide a metal coordination compound of the formula (1) suitable as a luminescent material for broader wavelength range luminescence of an organic EL device and exhibiting a higher phosphorescence yield and a shorter phosphorescence life (time). An organic luminescence device (EL device) using the metal coordination compound according to the present invention stably exhibits high-efficiency luminescence.
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An organic EL device includes a luminescence layer containing, as a luminescent material allowing a high-luminescence and high-efficiency luminescence for a long period of time, a metal coordination compound represented by the following formula (1): LmML′n, wherein M denotes Ir, Pt, Rh or Pd; L denotes a bidentate ligand; L′ denotes a bidentate ligand different from L; m is an integer of 1, 2 or 3; and n is an integer of 0, 1 or 2 with the proviso that the sum of m and n is 2 or 3. The partial structure MLm is represented by a formula (2) or a formula (3) shown below, and the partial structure ML′n is represented by a formula (4) or a formula (5) shown below:
wherein CyN1, CyN2 and CyN3 independently denote a substituted or unsubstituted cyclic group containing a nitrogen atom connected to M; CyN4 denotes a cyclic group containing 8-quinoline or its derivative having a nitrogen atom connected to M; CyC1, CyC2 and CyC3 independently denote a substituted or unsubstituted cyclic group containing a carbon atom connected to M, with the proviso that the metal coordination compound is represented by the formula (2) when n is 0.
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RELATED APPLICATION INFORMATION
This application is a continuation of application Ser. No. 09/520,110, filed Mar. 7, 2000 now U.S. Pat. No. 6,322,493, which is a continuation-in-part of application Ser. No. 09/469,959, filed Dec. 21, 1999 now abandoned, which is a continuation-in-part of application Ser. No. 09/414,250, filed Oct. 7, 1999 now U.S. Pat. No. 6,224,541, which is a continuation-in-part of application Ser. No. 09/340,227, filed Jul. 1, 1999 now U.S. Pat. No. 6,179,775, each of which are herein incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to arrangements for the stimulation of females and more particularly to topical application of specialized stimulatory medicaments.
2. Prior Art
The unique properties of the clitoral sensitizing compounds described in my earlier co-pending patent application Ser. No. 09/469,959 encompasses the vasodilatation of clitoral blood vessels by the initial effect of menthol to facilitate and promote the absorption of L-arginine when topically applied to the mucous membrane of the clitoris. The L-arginine stimulates the nitric oxide synthase mediated production of nitric oxide to effect clitoral sensitivity, arousal, and erection by sustained vasodilatation. Both of these actions are specific to the topical application of the compound to the mucous membrane of the clitoris and presume an inert, non-active base or vehicle. In the menthol/L-arginine compound, the menthol actually acts as a vehicle to enhance the absorption of L-arginine.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to alternate preparations of menthol and related cooling compounds that comprises a class of single-source of botanical or essential oils that can be used individually or as a combination of several oils such as: Peppermint oil; Cornmint oil; Eucalyptus oil; Citronella oil; Indian turpentine oil; Camphor oil and Cinnamon oil.
In fact, all of the botanicals listed by Steinberg in “Frequency Use of Botanicals,” in Cosmetics and Toiletries magazine, Volume 113, October, 1998, (incorporated herein by reference) are members of this class of singe-source botanical or essential oils. Potentially, any of these referenced oils could evoke the menthol-like effect on the mucous membrane to facilitate or promote the topical absorption of L-arginine. In addition, known minor skin irritants can cause a profound reaction when topically applied to mucous membrane, such as redness, irritation, and reflex vasodilatation. This irritant reaction associated with vasodilatation shares some similarities with the menthol effect, and could quite effectively substitute for the menthol in promoting L-arginine absorption and actions. Salicylate and capsiatin are two of the commonly used minor skin irritants. Oil soluble vitamins (co-enzymes) A, D, or E, could also potentiate absorption of menthol, L-arginine, minor skin irritants, or any of the menthol-related cooling compounds. The oil soluble vitamins could be used to substitute for, or be used in addition to, any of the previously listed components in a topical clitoral sensitizing preparation.
The invention may further comprise alternate preparations for the base or the vehicle. Such biologically active agents (menthol or its substitutes) and L-arginine can be compounded in a non-biologically active base, or in a biologically active base that promotes absorption, a vehicle. Any base or vehicle is intended to liquefy at body heat and in the presence of moisture present in mucous membrane when topically applied to mucous membrane tissue. Campos and Eccleston is “Vitamin A Skin Penetration,” Cosmetics and Toiletries magazine, volume 113, July, 1998, describe and quantify how different vehicles influence and promote the hairy skin (keratinized stratified squamous epithelium) absorption of Vitamin A. Mucous membranes absorb solutions more readily than hairy skin, but display linear absorption potentials relative to the vehicles studies by Campos and Eccleston. An active vehicle may be engineered that synegistically functions to promote the absorption and actions of menthol, menthol-related compounds, biologically derived oils, minor skin irritants, oil soluble vitamins, L-arginine, or any combination of these.
There are solid/liquid state dynamics for the topical delivery of clitoral sensitizing compounds which cover any of the potential compounds for topical application to sensitize the clitoris because they can have different solid/liquid states at ambient and at body temperatures. A solid compound, such as exemplified by the Chap Stick® Lip Balm, A.H. Robbins Company, of Richmond, Va., could be directly applied to the undercarriage of the clitoris, and liquefy at body temperature and in the moisture inherent in mucous membrane tissue. Liquefied compounds are readily absorbed, dependent on various other factors described. A gel/cream or liquid compound could be directly applied to the clitoris for topical absorption. Like the solid-state compound, the gel/cream must liquefy before absorption can be effected. The dynamics of how rapidly a compound transforms from a solid state or gel/cream state to a liquid state could be controlled to evoke an almost immediate effect, or a relatively delayed effect, before absorption of the compound.
A crystalline related dissolution may be different from the temperature related dissolution of a solid or a gel/cream. Small crystals of menthol, L-arginine, or any of the previously described components, may be suspended in a base vehicle. Their availability for absorption would depend on their dissolution from a crystalline state to a liquid state. The crystalline effect may be designed to control the rate of absorption: for instance, whether the compound were available for absorption immediately on application, or if a delayed, sustained absorption over a period of time were desired. Both of these parameters could allow the discrete, private application of the clitoral-sensitizing compound in anticipation of intercourse, without knowledge of the partner.
Because the clitoral-sensitizing compounds are also intended to function independently without the preferred intercourse-related physical stimulation of the clitoris as taught in my aforementioned patent application Ser. Nos. 09/414,250, 09/340,227 and 09/469,959, the menthol/L-arginine compounds may also be arranged to be available in various strength to address the needs of all women. The menthol may be compounded in multiple strengths, ranging from 0.1% to 5%, and any increment in between. The L-arginine may also be compounded in multiple strengths ranging from 1% to 10%. The spectrum of different strengths may be compounded into a single delivery system, such as lip balm, or alternatively, in all of the potential delivery systems: solid, gel/cream, and liquid.
A single use or a multiple use delivery systems comprising clitoral-sensitizing preparations may be individually packaged within a small tube or packet for single use. Conversely, a multiple-dose reusable delivery system, like a tube of hand cream or toothpaste, or a stick of lip balm, may be packaged for personal use.
The apparatus and methods to deliver a topical preparation to the clitoris may be comprised of a solid or semi-solid compound that may be directly applied to the undercarriage of the clitoris regardless of the use of a single-or multiple-use delivery system. The clitoral contact area of the solid or semi-solid compound in one preferred embodiment will have a notch to increase the surface area and clitoral contact of the compound. The notch is arranged with a height of 0.5 to 2 centimeters, and a maximum width of 2 centimeters at the rim of the notch. A properly designed concave notch will topically apply the compound to the 180 degree undercarriage of the clitoris. With proper directions for use, the application surface will initially contact the vestibular tissue at the base of the clitoris, to spread the compound on the entire clitoris.
A gel/cream or liquid compound would be applied to the clitoris with the same motions, but would require a different type of application device. The gel/cream or liquid could be applied by “roller balls” like those used to apply viscous deodorants, by a sponge-type applicator, or by a brush type of system. Any of the delivery devices for gel/cream or liquids could be designed to increase the surface area of the applicator tip and generally use the concave notch described for the solid compounds. The gel/cream and liquid applicators would have either a single-use reservoir or a multi-use reservoir. All of the delivery devices would have a cap that would seal the device before the initial use, and protect the applicator tip from contamination before use. Multi-use devices would have a resealing cap.
The invention thus comprises a hand-manipulable, clitoral stimulant-applying applicator for use to apply a clitoral stimulating compound to the clitoral area of the human female, comprising: a reservoir for containment of a clitoral stimulating compound; a clitoral stimulating compound in said reservoir; and a removable cover on the reservoir to expose the compound to permit said compound to be applied topically. The cover may comprise a removable cap. The reservoir may comprise a tube and said cover. The compound may comprise a gel. The compound may comprise a cream. The compound may comprise a fluid liquid. The compound may comprise a semi-solid. The semi-solid compound may have a notch on its distalmost end to facilitate the application of the compound. The applicator may includes a brush thereon. The applicator may include a sponge thereon. The applicator may include a roller ball arrangement thereon. The compound may be comprised of a mixture of menthol and L-arginine. The compound may have components selected from the group consisting of: Peppermint oil, Cornmint oil, Eucalyptus oil, Citronella oil, Indian turpentine oil, Camphor oil and Cinnamon oils. The compound may have components selected from the group consisting of: Salicylate, capsiatin, and oil soluble vitamins (co-enzymes) of A, D, or E.
The invention also includes a method of sensitizing the clitoris of a human female, comprising the steps of: applying a compound of sensitizing agent to the clitoris; and selecting a component of said sensitizing agent from the group consisting of: Peppermint oil, Cornmint oil, Eucalyptus oil, Citronella oil, Indian turpentine oil, Camphor oil, Cinnamon oils, Salicylate, capsiatin, and oil soluble vitamins (co-enzymes) of A, D, or E. The steps may include placing the sensitizing agent in a reservoir of an applicator; arranging a cover on the applicator to protect the agent in the reservoir. The applicator may include a brush. The applicator may include a roller at one end thereof. The applicator may include a sponge at one end thereof. The sensitizing agent comprises a semi-solid stick having a “V” notch on a distal end thereof to facilitate application of the agent to a clitoris.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and advantages of the present invention will become more apparent when viewed in conjunction with the following drawings in which:
FIG. 1 is a front elevational view of a solid compound single-use applicator;
FIG. 2 is a view taken along the lines 2 — 2 of FIG. 1;
FIG. 3 is a front elevational view of a solid compound multiple-use applicator;
FIG. 4 is a view taken along the lines 4 — 4 of FIG. 3;
FIG. 5 is a front elevational view of a gel/cream/liquid compound single-use applicator;
FIG. 6 is a front elevational view of a gel/cream/liquid compound single or multiple use brush applicator;
FIG. 7 is a view of the applicator shown in FIG. 6, with its cap off;
FIG. 8 is a side elevational view, in section, of the applicator cap shown in FIG. 6;
FIG. 9 is front elevational view of a gel/cream or liquid applicator with roller balls; and
FIG. 10 is a view taken along the lines 10 — 10 of FIG. 9 .
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the invention and the drawings in detail, alternate preparations of menthol and related cooling compounds comprises a class of single-source of botanical or essential oils that can be used individually or as a combination of several oils such as: Peppermint oil; Cornmint oil; Eucalyptus oil; Citronella oil; Indian turpentine oil; Camphor oil and Cinnamon oils, as compounds of the present invention. Any of these referenced oils could evoke the menthol-like effect on the mucous membrane to facilitate or promote the topical absorption of L-arginine. Salicylate and capsiatin, two commonly used minor skin irritants and oil soluble vitamins (co-enzymes) A, D, or E, could also potentiate absorption of menthol, L-arginine, minor skin irritants, or any of the menthol-related cooling compounds. The oil soluble vitamins could be used to substitute for, or be used in addition to, any of the previously listed components in a topical clitoral sensitizing preparation. Such solid/liquid state dynamics for the topical delivery of clitoral sensitizing compounds which cover any of the potential compounds for topical application to sensitize the clitoris because they can have different solid/liquid states at ambient and at body temperatures.
A gel/cream or liquid compound could be directly applied to the clitoris for topical absorption. Like the solid-state compound, the gel/cream must liquefy before absorption can be effected. The dynamics of how rapidly a compound transforms from a solid state or gel/cream state to a liquid state could be controlled to evoke an almost immediate effect, or a relatively delayed effect, before absorption of the compound.
A crystalline related dissolution may be different from the temperature related dissolution of a solid or a gel/cream. Small crystals of menthol, L-arginine, or any of the previously described components, may be suspended in a base vehicle. Their availability for absorption would depend on their dissolution from a crystalline state to a liquid state. The crystalline effect may be designed to control the rate of absorption: for instance, whether the compound were available for absorption immediately on application, or if a delayed, sustained absorption over a period of time were desired. Both of these parameters could allow the discrete, private application of the clitoral-sensitizing compound in anticipation of intercourse, without knowledge of the partner.
A single use or a multiple use delivery systems comprising a clitoral-sensitizing preparation 10 may be individually packaged within a small tube 12 or packet 14 for single use, as shown in FIGS. 1, 2 and 5 . The tube 12 may be gripped by the thumb and first finger, and the compound preparation thereon applied as desired.
The packet 14 shown in FIG. 5 has a break-away seal 15 which permits the gel/cream or liquid 10 therein to be readily applied by merely squeezing the packet 14 . Conversely, a multiple-dose reusable delivery system, like a tube of hand cream or toothpaste, or a stick of semi-solid compound, clitoral-sensitizing balm 16 , may be packaged for personal use, as shown by the “lipstick-like” rotatively adjustable applicators 18 in FIGS. 3 and 4. This adjustable applicator 18 has a cap 20 to cover the balm compound 16 .
The apparatus and methods to deliver a topical preparation to the clitoris may also be comprised of a solid or semi-solid compound that may be directly applied to the undercarriage of the clitoris regardless of the use of a single-or multiple-use delivery system. The clitoral contact area of the solid or semi-solid compound in one preferred embodiment will have a notch “V” to increase the surface area and clitoral contact of the compound 16 , as shown in FIGS. 1 and 3. The notch “V” is arranged with a height of 0.5 to 2 centimeters, and a maximum width of 2 centimeters at the rim of the notch “V”. A properly designed concave notch “V” will topically apply the compound 16 to the 180 degree undercarriage of the clitoris. With proper directions for use, the application surface will initially contact the vestibular tissue at the base of the clitoris, to spread the compound on the entire clitoris. A gel/cream or liquid compound 30 of the present invention would be applied to the clitoris with the same motions, but would require a different type of application device. The gel/cream or liquid compound 30 may be applied by “roller balls” 32 like those used to apply viscous deodorants, as shown in FIGS. 9 and 10, supported within a foraminous top 34 , covered when not needed, by a cap 46 . The gel/cream or liquid compound 30 may also be applied by a sponge or brush 40 secured to a top 42 in a reservoir 44 , as shown in FIGS. 6 and 7. A cap 48 , shown also in FIG. 8 may include a removable seal 50 , both of which are arranged to be removable to expose the sponge or brush 40 and openings 46 in the reservoir 44 to supply the fluid compound thereto. Any of the delivery devices for gel/cream or liquids could be designed to increase the surface area of the applicator tip and generally use the concave notch described for the solid compounds. The gel/cream and liquid applicators would have either a single-use reservoir or a multi-use reservoir. All of the delivery devices would have a cap “C” that would seal the device before the initial use, and protect the applicator tip from contamination before use. Multi-use devices, such as shown in FIGS. 3, 4 , 6 , 7 and 9 would have the resealing cap 48 for their protection.
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The present invention comprises a method and apparatus such as a hand-manipulable, clitoral stimulant-applying applicator for use to apply a clitoral stimulating compound to the clitoral area of the human female. A reservoir in the apparatus is arranged for containment of a clitoral stimulating compound, with a clitoral stimulating compound in said reservoir. A removable cover is arranged on the reservoir to expose the compound to permit the compound to be applied topically.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a nonprovisional of U.S. Provisional Application No. 60/950,082, filed Jul. 16, 2007, the entire disclosure of which is hereby incorporated by reference herein.
BACKGROUND
[0002] In a world where the art of technology is actively and favorably affecting various parts of our lives, it becomes necessary to apply this revolutionary art to all aspects of the progressive lifestyle. Specifically, the financial realm of people's lives has recently received little of technology's attention—Yes, there are some programs meant to facilitate and advocate increased financial management such as SAP®, QuickBooks®, Microsoft Money®, Quicken®, and Peachtree®—but in no way have these applications been upgraded to meet the standards of other aspects of our lives.
[0003] These aforementioned aspects are often vital to society's success; conversely, they may sometimes be auxiliary indulgences used solely for entertainment purposes. An example would be the notorious iPod®, which has received much attention in recent years. From October 2001 to January 2007, seven distinct generations have been released, each with a new, innovative addition, whether it be additional storage space, a color screen, or video capabilities.
[0004] On the contrary, QuickBooks, the leading financial management software in the United States, has yet to take full advantage of the recent boom in technology since its debut in 1992. Similarly, the world's first accounting software, Peachtree, has only updated its application by releasing new versions.
[0005] In the current United States, poverty has become a primary concern for its citizens—In 2006, approximately 13 percent of all U.S. citizens fell under the poverty threshold. This was an abrupt and undoubtedly unfavorable change, as in 2000 only 11.3 percent were considered to be “poor.” Much of this increase in destitution can be attributed to poor management of money, as it is tough for many to juggle the different expenditures—food, clothing, rent, etc.—and to thereby balance them with an income.
[0006] The logical conclusion, therefore, would be to take advantage of the recent expansion of technology, and to directly apply it to the waning state of finance. In essence, a combination of these currently antipodal worlds can only result in an advantageous outcome.
DESCRIPTION OF THE DRAWINGS
[0007] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
[0008] FIG. 1 demonstrates an illustrative environment in which aspects of the disclosed and claimed subject matter may operate, including personal wireless communication devices in communication with a wireless service which is further coupled to a receiving server over a network connection;
[0009] FIG. 2 is a block diagram that demonstrates components (both logical and actual) of an illustrative personal wireless communication device suitable for implementing aspects of the disclosed and claimed subject matter;
[0010] FIG. 3 is a block diagram that demonstrates components (both logical and actual) of an illustrative receiving computing device suitable for implementing aspects of the disclosed and claimed subject matter; and
[0011] FIG. 4 illustrates a flow diagram for general entry and processing of financial/transaction information on a personal wireless communication device.
DETAILED DESCRIPTION
[0012] Disclosed is a system and method for financial management including an application for use with mobile devices, especially wireless phones and hybrid phone/PDA devices. Examples include, by illustration and no by limitation, RIM's Blackberry® devices, Apple's iPhone®, and the like. In addition to providing a tool to manage finance combined with the freedom of a cell phone, the disclosed subject matter provides for the wireless transfer of the client's financial information to other devices including servers, desktops, and laptops, thereby increasing the possibilities and likelihood of appropriate financial management of expenditures and the like.
[0013] Another aspect of the disclosed subject matter that will vastly affect the financial world is the transfer of information of financial information to various destinations via email. For example, using the disclosed systems and methods, employees will be enabled to instantly send information (such as expenditures) and/or reports to their company's headquarters with the click of a button. This information can be in the form of tables, charts, or diagrams, and can be presented by category, date, or time period. With this variety of options, clients and corporations will be more aware of, for example, which expenses are overly exorbitant and need attention, or the time of month at which spending a bit of extra money on a nice dinner wouldn't hurt.
[0014] The systems and methods allow for inputs for various categories, including expenses and incomes. Upon receiving either, the client can immediately enter the amount in the appropriate date and category, be it transportation, taxes, or food. Later, a report (suitable for the device upon which the client is using) can be viewed to see where a majority of money was spent, or whether or not the income will be able to cover the expenditures. Similarly, various reports can be generated on those services or other computing systems that receive the information from the client's device.
[0015] According to aspects of the disclosed subject matter, both personal and business categories can be supported, thereby separating the two distinct categories. The client would therefore be able to avoid sending personal financial information to his/her managing company. Of course, it should be appreciated that there could be, theoretically, any number of categories to which the user may direct financial information. Thus, discussion of two categories should be viewed as illustrative and not limiting upon the disclosed subject matter.
[0016] The wide base of people that would be affected by the invention is a critical aspect of its distinctiveness. In today's world, people of all varieties are well-acquainted with technology—from the curious eight year old to the sagacious grandfather, almost all members of society own the seemingly essential technologies like the cell phone. Therefore, people of all ages and situations would benefit from the disclosed subject matter; the young girl can find the best way to spend her allowance just as the jaded adult can balance his/her incomes and expenses.
[0017] Problems with memory space and features are inevitable to emerge with mobile devices. However, the invention's back-end capabilities are an effective way to solve this problem: By having the option of transferring financial information to a desktop, laptop, or server, a client will always be able to manage his/her financial world most effectively while also keeping sufficient storage space on a cell phone.
[0018] Yet another aspect of the disclosed subject matter includes high configurability with regard to uploading information to a server (or other computing device configured to receive. For example, the software application that resides on the cell phone (or other communication device) may be configured to automatically initiate an upload of the financial information to the receiving server when the memory usage for the financial information reaches a threshold amount of the total capacity allotted to store the financial information. Alternatively, the software application may be configured to upload the financial information in an on-demand manner according to user directives, or to automatically upload the information at a certain time of day and/or when the rates for transmitting the financial information may be lowest. Still further, the software application may be configured to upload the financial information as it is entered such that the receiving host can have real-time updates of financial expenditures. Of course, in addition to uploading information over the wireless phone network, the software may be configured to upload the information via a direct line (such as via a USB or FireWire connection) if the user would prefer.
[0019] While many hand-held wireless phones now include keypads that enable a user to enter text information relatively easily, not all users will have such capabilities or want to enter a lot of financial information in that manner. Accordingly, the software may be configured to permit the user to enter entirely text based information, a combination of text and voice annotations, or voice information. As an example of a combination, a user may make an entry with an amount (say of dinner) and then provide a voice annotation as to the purpose and attendees of the dinner such that both the text-entered amount and the voice annotation are uploaded to the receiving server.
[0020] Regarding FIG. 1 , this pictorial diagram demonstrates an illustrative network environment 100 in which aspects of the disclosed and claimed subject matter may operate, including personal wireless communication devices 102 and 104 in communication with a wireless service 106 which is further coupled to a receiving server 108 over a network 110 . Also shown in the illustrative network environment 100 is a personal computing device 112 , illustrated as a laptop but which may be any type of computing device. The personal computing device 112 corresponds to a user's computer where accounting and/or financial software would typically be maintained.
[0021] According to aspects of the disclosed subject matter, a user can record financial information on a personal wireless communication device at a remote location, such as the wireless telephone/PDA combination 102 , transmit the data 114 over the wireless service 106 and network 108 to a receiving server 110 , an online storage service (not shown), or the user's computing device 112 .
[0022] Turning to FIG. 2 , this figure is of a block diagram that demonstrates components (both logical and actual) of an illustrative personal wireless communication device 200 suitable for implementing aspects of the disclosed and claimed subject matter. The wireless communication device 200 includes a processor 202 that executes computer executable instructions from a memory 204 . Those skilled in the art will appreciate that the memory 204 may include read-only memory (ROM), random-access memory (RAM), persistent data storage 210 , flash memory devices, and the like. The memory 204 stores executable modules 206 and 208 that may be executed by the processor 202 to carry out various functions for gathering, categorizing, and transferring financial information/data from a user to an external receiving service, server 110 , and/or computer 112 .
[0023] The personal computing device 200 typically includes one or more user input devices, such as user input device 214 , by which a user interacts with the personal computing device to enter financial information. Examples of such user input devices includes a keypad, a touchpad, a camera, and the like. The personal computing device 200 further typically includes at least one user output devices, such as user output device 216 . As those skilled in the art will appreciate, an exemplary user output device is an LCD screen upon which information may be displayed. In some cased, the user output device 216 may be a speaker on the user's personal wireless communication device 200 where all output is audio output.
[0024] Further illustrated in the personal wireless communication device 200 is a wireless communication interface 212 . Wireless communication interfaces are well known in the art, and may use a variety of communication technologies including, but not limited to TDMA, GSM, UMTS, Wi-Fi, Wi-Max, CDMA-2000, Bluetooth, Edge, 802.11 protocols, IR, and the like. While not illustrated, the personal wireless communication device 200 may further include a wired communication interface, such as a USB communication port, Firewire port, parallel port, serial port, and the like. Using the wired communication interface, a user may cause the personal wireless communication device 200 to upload data temporarily stored on the personal wireless communication device directly to the user's computer 112 .
[0025] One of the many advantages of the disclosed subject matter is that the data records that are generated for each financial transaction entry may be placed in any number of formats and/or prepared for any number of financial systems. For example, the data records may be formatted according to general ledger and accounting standards such that the records transmitted to receiving servers can be automatically (rather than manually, as is the current practice) incorporated into a business's finance system. Alternatively, the output may be configured to comply with the formats required for personal finance software such as Quicken. Additionally, the data record may be converted into a tab-delineated, text based document and emailed to a particular address. Given that the format of the data record corresponding to the financial transaction is know, information from the record can be automatically extracted and fed into charts, spreadsheets, and the like. Categorizing each entry can be used to determine the output of the system.
[0026] Turning now to FIG. 3 , this figures is of a block diagram of an illustrative receiving computing device 300 suitable for receiving and processing financial data from a personal wireless communication device 200 . The receiving computing device 300 includes a processor 302 that executes computer executable instructions retrieved from a memory 304 . As discussed above, those skilled in the art will appreciate that the memory 304 may include read-only memory (ROM), random-access memory (RAM), persistent data storage 310 , flash memory devices, and the like. The memory 304 stores executable modules, such as executable modules 306 and 308 , that are executed by the processor 302 to carry out various functions for gathering, categorizing, and storing finance data received from a user's wireless communication device 200 .
[0027] FIG. 3 is further illustrated as including a network interface that enables the receiving computing device 300 to connect to a network, such as the Internet, for receiving user finance data. While not shown, the receiving computing device 300 may also include a wireless communication interface which, like the user's personal communication device 200 , sends and receives data wirelessly, including finance data.
[0028] As is well appreciated, not all personal wireless communication devices include keypads that enable a user to enter robust finance information. For example, a wireless telephone may include a 10-key numeric keypad that could be used to enter alphabetic and numeric characters. Of course, a user would find entering complete finance detail of a transaction into the wireless device to be onerous and, therefore, would not make use of the option to do so. On the other hand, a wireless telephone is well suited to receiving voice signals and, when coupled with some simple buttons presses on the wireless telephone, could store robust finance information regarding a business or personal expense. For example, after a business meal, the user may activate a program on the wireless communication device 200 to enter finance information, press a few simple buttons and/or select menu items that may include general ledgers and accounting standards to indicate whether this new entry is personal or business, that it is for a meal, and then provide an audio description of the cost by speaking into the device (while it records), enumerate the people at the meal, indicate the subject matter that was discussed, and (either by voice or by keypress) temporarily store the finance entry on the telephone (for later processing.) Still further, when the telephone is equipped with a camera, the user may also attach one or more images of the receipt to the financial entry.
[0029] As mentioned above, the personal wireless communication device 200 may be configured to transfer the finance information temporarily stored on the computing device in an on-demand manner, when a storage threshold is exceeded, at a specific time of day, only when current power reserve levels exceed a predetermined threshold, according to specific user instructions, and the like as well as various combinations of the above.
[0030] Turning now to FIG. 4 , this figure is of a flow diagram illustrating a routine 400 for general entry and processing of financial/transaction information on a personal wireless communication device 200 . At block 402 , the user initiates creation of a new financial entry. The user may do this through a variety of user interactions available for the particular wireless communication device, such as but not limited to a selection of a menu, pressing a particularly configured button, and the like.
[0031] At block 404 , the user optionally identifies a category for the financial entry. For example, the category may be for a personal expense, a business expense, general ledgers and accounting standards, and the like. Thereafter, at block 406 , the personal wireless communication device 200 receives the financial data from the user. As already indicated, the user may input information regarding the particular financial entry by way of keypad, voice annotation, pictures and/or video, via a stylus on a touch or pressure sensitive touchpad, or combinations of the above.
[0032] After entering the information, at block 408 , the financial data associated with the entry is stored in temporary storage for later transmittal to the user's computer, a receiving service or server, or the like. At some point thereafter (whether by periodic updates, at the direction of the user, when a storage threshold is reached, or the like), at block 410 the entry is uploaded to a receiving computer and/or service where the user can further process the information. Thereafter, the routine 400 terminates.
[0033] While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
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Systems and methods for processing financial transactions at remote locations on wireless communication devices is presented. A wireless communication device is configure with executable modules such that the device can interact with a user to, first, receive a first user indication to create a data record corresponding to a financial transaction on the wireless communication device. Thereafter, the device creates a data record corresponding to the financial transaction. Information corresponding to the financial transaction on the wireless communication device is received into a data record and stored in a temporary data store on the wireless communication device. Thereafter, the wireless communication device transmits the data record to a receiving service for processing in a financial application.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent application Ser. No. 11/036,809, filed Jan. 14, 2005 entitled “Partition Assembly Made With Multiple Ply Partitions” which is fully incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates to a partition assembly for dividing the space inside a container or box; more particularly to a partition assembly made of slotted, multiple ply partitions.
DESCRIPTION OF THE PRIOR ART
[0003] In the storage, shipment or display of parts or merchandise, it is a common practice to divide the interior of a box or container into a plurality of individual cells. The interior of a box or container is typically separated by a series of dividers, one set of parallel dividers being orthogonal to a second set of dividers. The dividers separate the interior of the container into a plurality of individual holding cells each of which is intended to hold a separate item for display and/or shipment. The division of the interior of the box or container helps prevent the items therein from contacting one another and breaking during shipping. The division or partitioning of the container also aids in the loading and unloading of the items therein, as well as inventorying the contents of each box or container.
[0004] The dividers typically are slotted and arranged in an orthogonal relationship to divide the interior of the box or container into a desired number of holding cells. The dividers are slotted in a manner that enables the dividers to engage with one another at the location of the slots so that the dividers form an orthogonal grid or matrix. Typically the dividers are made of the same material as the material of the box or container, plastic or paperboard. However, the dividers may be constructed of any suitable material with sufficient rigidity to prevent the contents of the container from contacting one another and being damaged.
[0005] One disadvantage with known partition assemblies is that the upper edges of the partitions may have exposed sharp edges. For example, corrugated plastic partitions may have sharp upper edges created by cutting a sheet of corrugated plastic to the desired partition size. Such an exposed upper edge of the partition may damage products or parts being loaded into or unloaded from the cells of the container in which is located the partition matrix or assembly. Partition assemblies incorporating partitions having exposed sharp upper edges may require additional clearance between the parts being either loaded or unloaded and the upper edges of the partitions.
[0006] Another disadvantage of such partition assemblies is that the person loading or unloading parts or products into or from the cells of the container may cut or scrape their knuckles or hands on the exposed upper edges of the partitions when loading or unloading parts or products.
[0007] Additionally, the stiffness of the partitions of the assembly is dictated by the material from which the partitions are made. The stiffness of the partitions may not be altered without changing the material from which the partition is made.
[0008] U.S. Pat. No. 2,647,679 discloses a partition assembly which separates the interior of a box or container into a plurality of cells. The partitions of the assembly disclosed in this patent are formed by folding a blank of material along a fold line so as to create a rounded smooth upper edge. The material is disclosed as being paper board or similar material.
[0009] Another partition assembly for dividing the interior of a container is disclosed in U.S. Pat. No. 4,375,263. The partitions of this assembly are similarly rounded along their upper edges and are made of transparent vinyl sheets.
[0010] In each of these prior art partition assemblies, the opposed plies of the dividers or partitions formed by folding a blank of material are not secured to each other. Consequently, the opposed sides or plies of the partitions are not secured to each other and may be easily separate, thereby expanding into the cells of the container defined by the partition assembly. Consequently, the partitions may contact the products or parts stored in the cells and damage them. Additionally, the partition plies may easily tear or otherwise be damaged. Upon assembly or disassembly of the partition matrix, one or more portions of the partitions may tear and hence cause disassembly of at least a portion of the partition matrix.
[0011] It therefore has been one objective of the present invention to provide a double-ply partition for use in a partition assembly in which the plies are secured together.
[0012] It has been a further objective of the invention to provide a method of manufacturing a double-ply partition for use in a partition assembly which is secure and may not be easily disassembled.
[0013] It has been another objective of the present invention to provide a double-ply partition for use in a partition assembly in which the partition has the desired degree of stiffness.
SUMMARY OF THE INVENTION
[0014] The partition assembly of the present invention which accomplishes these objectives comprises at least one first slotted partition intersecting with at least one second slotted partition at an intersection. The intersecting first and second slotted partitions form a plurality of holding cells into which different parts are stored for shipment or display.
[0015] Each first slotted partition has at least one slot extending inwardly from an edge of the first slotted partition. Likewise each second slotted partition has at least one slot extending inwardly from an edge of the second slotted partition. Preferably the slots are evenly spaced in order to make the holding cells which are defined by the intersecting partitions of identical dimensions. However, the slots may be located at any desired locations. In one embodiment, each of the slots of a first slotted partition extends inwardly from an edge of the first slotted partition to approximately the midpoint of the first slotted partition. Each of the slots of a second slotted partition extends inwardly from an edge of the second slotted partition to approximately the midpoint of the second slotted partition.
[0016] In one embodiment of the present invention, the partition is formed of a multilayered material folded in half and secured to itself. The fold creates a rounded upper edge at the fold line which is smooth and has a continuous surface with the outer side walls or skins of the partition. The partition blank comprises an inner layer of foam, preferably polyolefin foam, and an outer layer, skin or facegood. In one embodiment, the inner foam layer is bonded directly or laminated to the outer layer. The outer layer may be made of woven polyester, non-woven polypropylene, foamed or solid polyolefin or other material such as latex or non-polyolefin plastic. The outer layer may be selected as appropriate to protect or prevent surface damage to the products being stored and/or shipped in the cells of the container.
[0017] In an alternative embodiment, a desired stiffness or rigidity may be created in the partition by inserting into the partition blank from which the partition is made a thin plastic skin or middle layer between the inner foam layer and the outer layer or facegood. By altering the thickness and/or mechanical properties of this middle layer, or by omitting it altogether, the desired level or degree of stiffness of the partition may be achieved during the manufacturing process.
[0018] In an alternative embodiment, the partition blank may be made solely of one foam layer without any outer layer or facegood.
[0019] The method of manufacturing the multiple ply partition comprises multiple steps. Although the method is described with respect to one preferred embodiment, the method may be used with any of the embodiments contemplated by this invention.
[0020] In one instance, a multiple layered partition strip or blank having an outer skin secured to a foam interior is first provided. This partition blank may be made using any desired known method such as co-extrusion, lamination, etc.
[0021] The partition blank is folded so as to create two opposed plies and a smooth edge connecting the plies. The foam interior layer of at least one of the plies is heated with a heat source. The heat source is placed in such proximity to the contacting portions of the partition plies so that heat from the heat source causes the foam portion of at least one of the partition plies to become at least partially molten. The heat source is then distanced from the partition plies and the foam portions of the partition plies allowed to cool under pressure, thereby creating a securement of the foam layers or portions of the partition plies to create a unitary partition having a foam interior portion surrounded by an outer skin. The heat source may be hot air or any other suitable heat source.
[0022] In this manner, the plies of the partition are parent welded or fused together along their interior or inner surfaces. For purposes of this document, the term “parent weld” or “parent weldment” refers to a weldment of two contacting partition plies welded, fused or secured together without the use of any additional material other than the material of the partition plies themselves. The present invention is not intended to be limited strictly to foam, partition plies made of corrugated plastic may be parent welded together in accordance with the present invention in a manner disclosed and taught in assignee's U.S. Pat. No. 5,788,146, which is fully incorporated herein.
[0023] One advantage of using a partition blank having a foam interior made of a polyolefin foam is that the two plies of the partition blank may be secured or fused together using only heat, thereby eliminating the need for additional material such as adhesive, staples or other fasteners. The omission of the additional material may reduce the labor and material cost of making the slotted partition. The securement of the two plies together using only heat may not be possible or economically desirable with other materials such as paperboard, commonly used to make partitions.
[0024] Such a process of welding opposed plies of a partition together without the use of any additional material other than the material of the partition plies to form a multiple ply partition having the desired stiffness is quick, economical and allows many multiple ply partitions to be mass produced with low material and labor costs, Once the portion of at least one ply is separated from the heat source and allowed to cool, the plies are parent welded together in a permanent relationship.
[0025] An alternative method of joining the foam interior layers of the plies of the partition is to adhesively secure them together. Other means of securing the foam interior layers of the folded partition plies may used if desired.
[0026] This method of making a two-ply partition by securing opposed plies of the partition together is quick, easy and inexpensive. The opposed plies of the partition are permanently secured to each other, making the partition non-disassembling and enhanced by being double layered or double ply without using any additional material or tools.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a perspective view of the partition assembly of the present invention located inside a container;
[0028] FIG. 2 is a perspective view of the construction of the partition assembly of FIG. 1 illustrating a plurality of first slotted partitions and a plurality of second slotted partitions;
[0029] FIG. 3 is a cross-sectional view taken along the line 3 - 3 of FIG. 2 ;
[0030] FIG. 3A is a cross-sectional view of an alternative embodiment of a partition used in accordance with the present invention having a middle layer; and
[0031] FIG. 4A is a diagrammatic side elevational view illustrating a method of manufacturing partition blanks according to one embodiment of the present invention;
[0032] FIG. 4B is a diagrammatic side elevational view illustrating a method of manufacturing a roll of material used to make partition blanks according to another embodiment of the present invention;
[0033] FIG. 4C is a diagrammatic side elevational view further illustrating the method of manufacturing partition blanks according to the method of FIG. 4B ;
[0034] FIG. 5A is a perspective view of a partition blank;
[0035] FIG. 5B is a perspective view illustrating the partition blank of FIG. 5A being folded;
[0036] FIG. 5C is a perspective view illustrating the interior foam layers of opposed plies of the partition blank of FIG. 5A being heated;
[0037] FIG. 5C 1 is a perspective view illustrating the interior foam layers of opposed plies of the partition blank of FIG. 5A being joined without heat;
[0038] FIG. 5D is a perspective view illustrating the heated partition blank of FIG. 5C cooling under pressure according to one embodiment of the present invention;
[0039] FIG. 5E is a perspective view illustrating a method of cutting a two-ply partition to size; and
[0040] FIG. 5F is a perspective view illustrating a finished slotted partition according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0041] Referring to the drawings and particularly to FIG. 1 , there is illustrated a partition assembly 10 for dividing the space inside a container S. Although one type or configuration of container 5 is illustrated in FIG. 1 , the partition assembly 10 of the present invention may be used in any type of container or box. As illustrated in FIG. 2 , the partition assembly 10 comprises a plurality of parallel first slotted partitions 12 intersecting with a plurality of parallel second slotted partitions 14 .
[0042] As shown in FIG. 2 , each first slotted partition 12 has a rounded upper or top edge 16 , a planar bottom edge 18 and two opposed side edges 20 . Likewise each second slotted partition 14 has a rounded upper or top edge 22 , a planar bottom edge 24 and two opposed side edges 26 .
[0043] Each first slotted partition 12 has at least one slot 28 which extends downwardly from the top edge 16 of the first slotted partition 12 to approximately the midpoint of the first slotted partition 12 . The slots 28 may be evenly spaced apart in order that the individual holding cells 7 of the partition assembly may be evenly sized. See FIG. 1 . Alternatively, the slots 28 of the first slotted partitions 12 may be unevenly spaced in order to form holding cells of the partition assembly of differing sizes to accept different sized parts. The slots 28 are shown as being vertical but may be horizontal if the partition assembly 10 is placed on edge.
[0044] As shown in FIG. 2 , each second slotted partition 14 has at least one slot 30 extending upwardly from the bottom edge 24 of the second slotted partition 14 to approximately the midpoint of the second slotted partition 14 . The slots 30 of the second slotted partitions 14 may also be evenly spaced in order so that the holding cells 7 of the partition assembly 10 may be evenly sized. Again see FIG. 1 . Alternatively, the slots 30 may be unevenly spaced in order to form holding cells of the partition assembly of differing sizes adapted to accept different sized parts. The slots 30 are shown as being vertical but may be horizontal if the partition assembly 10 is placed on edge.
[0045] In one embodiment of the present invention each of the first and second slotted partitions 12 , 14 is made of a multilayered material. Each of the partitions 12 , 14 is a two-ply partition formed by the method shown in FIGS. 5A-5F and described below. FIG. 3 illustrates one of the partitions 12 in detail according to one embodiment of the present invention. As best illustrated in FIG. 3 , slotted partition 12 has two opposed plies 32 and 34 which are parallel to one another and joined together. The partition 12 has an outer layer or skin 36 assuming a generally inverted U-shaped configuration when the partition 12 is folded and the opposed plies 32 and 34 secured together. A wide variety of materials may be used for the outer layer or skin 36 including, but not limited to, woven polyesters, non-woven polypropylenes, foamed and solid polyolefins, latex, non-polyolefin plastics.
[0046] In the embodiment shown in FIG. 3 , inside the outer layer or skin 36 is a foam interior 38 comprising two layers 40 , 42 joined together along an interior surface 44 . A wide variety of materials may be used for the foam interior 38 of the partition 12 . In one preferred embodiment, the foam interior 38 is a polyolefin foam. However, other materials other than foam which may be welded or joined together may be used in accordance with the present invention. If desired, the outer skin 36 may be omitted, in which case, the entire partition 12 would be made of foam.
[0047] FIG. 3A illustrates an alternative embodiment of the present invention. In this embodiment, partition 12 a has an additional layer incorporated therein when compared to the partition 12 shown in FIG. 3 . In this alternative embodiment, the partition 12 a has an outer layer or skin 36 a , a foam interior 38 a comprising two layers 40 a , 42 a joined together along surface 44 a . In addition, a middle stiffening layer 46 is secured between the outer layer or skin 36 a and the foam interior 38 a . Like the outer layer 36 a of the partition 12 a , the middle stiffening layer 46 assumes a generally inverted U-shaped configuration when the partition 12 a is folded and the opposed plies 32 a and 34 a secured together as shown in FIG. 3A . A wide variety of materials may be used for the middle stiffening layer or skin 46 including, but not limited to, various plastics. If desired, additional middle stiffening layers of any suitable material (not shown) may be added to the partition blank. The partition 12 a has a smooth upper edge 75 a like the partition 12 shown in FIG. 3 created by the folding of a partition blank and securing the opposed plies 32 a , 34 a together in the manner described below.
[0048] Referring to FIG. 4A , to practice the method of this invention and form a multilayered partition blank 66 for subsequent use in forming a slotted two-ply partition like partition 12 shown in FIG. 3 for use in a partition assembly, a roll 48 of outer skin material is provided. As illustrated in FIG. 4A , a web of outer skin material 50 is unwound from the roll 48 and passed between two heated conveyors 52 . Other heat sources may used if desired. Another roll 54 , this one containing a web 56 of foam material is provided. The continuous web 56 of foam is unrolled from the roll 54 and passed into a nip 58 between rollers 60 . The webs 50 , 56 are joined together to create a multilayered web 62 . As shown in FIG. 4A , the multilayered web 62 is passed between cooling conveyors 63 and then cut with cutting device 64 to create a partition blank 66 . Any suitable means for cooling the multilayered web 62 other than conveyors may be used if desired. The cut multilayered partition blanks 66 are then stacked on top of one another to create a stack 68 .
[0049] FIGS. 4B and 4C illustrate another method of forming a cut multilayered partition blank 66 a . In this method, a roll 48 a of outer skin material is provided. As illustrated in FIG. 4B , a web of outer skin material 50 a is unwound from the roll 48 a and passed between two heated conveyors 52 a . Again, other heat sources other than conveyors may used if desired. Another roll 54 a , this one containing a web 56 a of foam material is provided. The continuous web 56 a of foam is unrolled from the roll 54 a and passed into a nip 58 a between rollers 60 a . The webs 50 a , 56 a are joined together to create a multilayered web 62 a . As shown in FIG. 4B , the multilayered web 62 a is then passed between cooling conveyors 63 a before being rolled up into a roll 70 . As illustrated in FIG. 4C , the multilayered web 62 a is unrolled from roll 70 and cut with cutting device 64 a at one or more desired locations to create a partition blank 66 a . The partition blanks 66 a are then stacked to create a stack 68 a.
[0050] Although FIGS. 4A-4C illustrate several method of manufacturing a multilayered partition blank, any other suitable known method of making a multilayered partition blank may be used such as co-extrusion, heat bonding or laminating several layers together.
[0051] Once a multilayered partition blank 66 , 66 a has been created, the multilayered partition blank is then formed into a two-ply slotted partition 12 using the method illustrated in FIGS. 5A-5F . For purposes of simplicity, FIGS. 5A-5F illustrate a method of creating a two-ply partition 12 . However, the same method may be used to create any partition used in accordance with the present invention. FIG. 5A illustrates a multilayered partition blank 66 in a planar flat orientation. FIG. 5B illustrates the multilayered partition blank 66 of FIG. 5A being folded along a fold line 74 so as to create two opposed plies 32 , 34 and a rounded smooth edge 75 joining the plies as seen in FIG. 3 . This smooth edge 75 becomes the upper edge of the partition 12 .
[0052] FIG. 5C illustrates the interior foam layers 40 , 42 of the opposed plies 32 , 34 , respectively being heated with a heat source 76 . In the illustrated embodiment, the heat source 76 blows hot air in the direction of arrows 78 to heat at least one of the interior foam layers 40 , 42 of the folded multilayered partition blank 66 . Of course, other types of heaters may be used in accordance with the present invention to heat at least one of the interior foam layers 40 , 42 of the folded multilayered partition blank 66 using any number of known methods.
[0053] FIG. 5D illustrates the interior surfaces 80 of the foam layers 40 , 42 of the opposed plies 32 , 34 , respectively, contacting each other and being under pressure from a pressure source 82 such as a press like the one illustrated in FIG. 5D . In the illustrated press 82 opposed plates 84 contact the outer skin 36 of the folded multilayered partition blank 66 . Rods 86 extending outwardly from the plates 84 and joined thereto cause the plates to move to and away from each other in a known manner. As shown in FIG. 5D , the plates 84 push the opposed plies 32 , 34 of the folded multilayered partition blank 66 together until the inner surfaces 80 thereof contact each other. Pressure is then applied by the press 82 as the opposed plies 32 , 34 of the folded multilayered partition blank 66 are cooled. The result is that the foam interior layers 40 , 42 of the opposed plies 32 , 34 of the multilayered partition blank 66 are fused together to create partition 12 . Although one type of press is illustrated any other type of device may be used to place the two opposed plies of the blank under pressure during the cooling process. Any method of cooling the opposed plies 32 , 34 of the folded multilayered partition blank 66 may be used in accordance with the present invention to fuse the interior foam layers 40 , 42 together including allowing the heated foam interior layer or layers to cool at room temperature.
[0054] As shown in FIG. 5C 1 , the heater may be omitted from the process of manufacturing a slotted partition 12 shown in FIG. 5F . In such a situation, adhesive 88 may be applied to the inner surfaces 80 of the opposed plies 32 , 34 of the folded multilayered partition blank 66 either before or after the multilayered partition blank 66 is partially folded as shown in FIG. 5B . Other known methods of securing the opposed plies 32 , 34 of the folded multilayered partition blank 66 may be used if desired.
[0055] FIG. 5E illustrates an unslotted two-ply partition 90 resulting from the securing of the opposed plies 32 , 34 of the folded multilayered partition blank 66 together in any manner including those described above. One or move knives 92 may be used to cut the unslotted two-ply partition 90 to the desired size.
[0056] As shown in FIG. 5F , slots 94 are then cut out of the unslotted two-ply partition 90 at the desired locations. The end result is a two-ply slotted partition 12 for use in a partition assembly such as the one 10 shown in FIGS. 1 and 2 .
[0057] While I have described only a few embodiments of my invention, I do not intend to be limited except by the scope of the following claims.
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A method of making a multiple ply slotted partition for use in a slotted partition assembly is provided. The slots of the partitions are engaged with each other at a plurality of intersections. The partitions are made by folding over a partition blank and securing a foam portion of the folded partition blank to itself. The foam may be heated before being cooled to secure opposed plies of the multiple ply partition together. The opposed plies of the partition are fused or parent welded together.
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BACKGROUND
1. Field
This disclosure relates to power control for a network of power stations. In a particular configuration, inverter power settings are performed for multiple solar panel stations.
2. Background
Solar photovoltaic systems produce electrical power. Electrical power is the product of current and voltage (I×V). Operating point and output power are interdependent in individual solar cells, and by extension in multi-cell panels and multi-panel arrays. The interdependence is characterized by a set of “I-V curves” as shown in FIG. 1 . Each I-V curve has a “Maximum Power Point” (MPP). This point is the operating point (voltage and current) at which the product of the panel's voltage and current provides the highest possible power output for a given set of environmental conditions (the peaks of the curves on the lower graph of FIG. 1 ). In viewing FIG. 1 , MPP high is the point on the voltage axis at which the power is maximum for the upper curve; MPP medium is the point on the voltage axis at which the power is maximum for the middle curve; and MPP low , is the point on the voltage axis at which the power is maximum for the lower curve. These are illustrative graphs, but a typical value for the MPP high curves would be 1000 W/m 2 and a typical value for the MPP low curves would be 200 W/m 2 . Ideally, each array of photovoltaic cells will be operating at its MPP to maximize the energy the photovoltaic system can capture. This ideal can be difficult to achieve because the I-V curve and MPP of a cell in the field is not constant.
A number of factors (“MPP factors”) influence the MPP of a given cell, module, panel, or array. They include irradiance (solar radiation energy received on a given surface area in a given time), cell temperature, spectral quality, ambient temperature, age of the panel(s), zenith and azimuth position of the sun, soiling, and wind speed. FIG. 2 is an illustrative example of MPP dependence on temperature for a fixed irradiance. FIG. 3 is an illustrative example of I-V and power curves for uniform and non-uniform irradiance. The examples are given for explanation and do not depict actual test results of a particular panel.
Referring to FIG. 3 , I-V curves 311 and 313 correspond to uniform and non-uniform irradiance, respectively. Power curves 321 and 323 correspond to uniform and non-uniform irradiance, respectively. MPP voltage for uniform irradiation is indicated at 331 . Under circumstances of non-uniform irradiance, it is possible to have a MPP voltage at a reduced voltage and it is possible to have local MPP≠global MPP, indicated at 333 .
In large scale PV systems, on the order of 100's of kilowatts to 10's or 100's of megawatts, a large number of panels or arrays of panels are used covering large ground surface areas. In these large systems, temperature-dependent losses in system components, such as wiring and transformers, also affect the MPP of the system.
Most of these factors are affected by local weather patterns, which are unpredictable and can change rapidly.
FIG. 4 is a diagram of a large solar installation with varying MPP factors for different arrays and array groups. A complication when planning large installations is that a large installation may cover variable terrain that includes hillsides, gullies, bodies of water, stands of trees, utility easements, or man-made structures. Each of these factors can affect the external MPP factors acting on nearby panels and make them behave differently from the reference. With reference to FIG. 4 , array Group A's location is “ideal”—a regular grid on flat, featureless land. Array Group B may get some shade from the hill for part of the day. Array Group C is on the hill. Array Group D may be affected by the trees (transient partial shade) or the stream and lake (reflected irradiance).
Localized differences in wind speed due to different ground levels or obstructions will affect ambient and cell temperature. Thus, landscape features can cause different panels or arrays to experience differing MPP factors at any given time.
Even if the terrain is perfectly featureless, as in some plains regions, broken or moving cloud patterns can affect the MPP of the PV panels below. The more area the installation covers, the more opportunities for shifting cloud patterns or fog patches to decrease the representative accuracy of a reference. Therefore, a need exists for a scheme to operate as close as possible to the MPP tailored to the needs of large installations.
Because PV systems of the past have been relatively small, 100's of watts to 100's of kilowatts, it has been customary to attempt to keep each module, panel, or sub-array within the system independently operating at its MPP. This function, and the systems and methods that perform it, are collectively known as “Maximum Power Point Tracking” (MPPT). The MPPT function typically resides in the inverters that receive DC power produced by the PV panels and convert it to AC power. MPPT methods may be classified as predictive (based on forecasts of likely MPP) or reactive (based on real-time feedback of actual system performance). In either case, each inverter is responsible for handling the MPPT function for the PV array it is serving.
Predictive MPPT approaches set the operating point of the PV array based on a predetermined constant value (selected to represent the average MPP) or based on an algorithm that adjusts the operating point based on inputs such as time of day, actual or predicted irradiance levels, or actual or predicted cell temperature. The disadvantage of predictive MPPT is that weather-related predictions may be wrong, and the power output will be sub-optimal if unexpected weather occurs.
Reactive MPPT methods use real-time measurements of changes in power, MPP factors, or both as feedback for closed-loop control of array operating points. These allow arrays to adapt to unexpected conditions. Reactive MPPT methods include algorithms where the operating point of the array is periodically varied until the MPP is determined. The disadvantage of reactive MPPT is that the array's power output is suboptimal for considerable periods of time while the operating point is being adjusted. The disadvantage can be compounded when rapid irradiance changes, as from fast-moving broken clouds, prolong hunt time; the MPP is a moving target while the I-V curve is changing with irradiance. The disadvantage can also be aggravated for partially-shaded arrays with “lumpy” I-V curves having multiple local maxima, an example of which is depicted in FIG. 3 ; the system may settle on a local MPP that is not the global MPP. Finally under quickly changing irradiance conditions, MPPTs often force the array to operate on the unstable portion of the I-V curve, which is the region beyond the peak operating point where power can drop off very quickly and the closed loop tracking system can become unstable.
“Reference” reactive MPPT methods track the MPP of a representative sample, rather than on each module, panel, array, or other independently controllable unit. The operating points of the other modules, panels, or arrays are then set to the sample's MPP. The disadvantage is that the representative sample is never completely representative due to the sample's size and differences in the MPP factors between the sample and the actual PV array. Reference MPPT schemes tend to mitigate the fluctuation problems; the larger the array, the less the reference cell's MPPT operations affect total output power. In applying this technique, the larger the number of panels in an installation, the greater the chance for error due to variability in the cell, panel or array manufacturing process. Increased geographical coverage of an installation results in increased variation in external MPP factors that the PV panels may experience. Both of these factors may compromise the accuracy of reference cells in tracking MPP for large arrays.
SUMMARY
Large-scale PV systems present opportunities for each inverter-connected array in the system to operate at or near its MPP using information from other arrays in the system. In a multi-unit, networked system of PV inverters, this approach sets the operating point of one or more inverters based on an MPP established elsewhere in the network. The “operating point” may be adjusted by adjusting voltage, current, or both. Unlike the reference MPPT methods of the prior art, it is possible to use a reference that is not a permanently fixed separate cell or sub-array, but an inverter-controlled array that may be selected dynamically with changing external conditions so that it always represents, with acceptable accuracy, the most representative sample. In large systems, there may be multiple representative references (hereinafter, a “master”) each used to set the operating point of other inverter-controlled arrays. Compared to the prior-art approach of each inverter-controlled array performing independent MPPT, the technique is able to increase plant energy capture and reduces fluctuations in the delivered power. Compared to fixed-reference MPPT, this ensures that the reference is optimally chosen for the prevailing external conditions.
DESCRIPTION OF THE DRAWINGS
The features and nature of the present disclosure will become more apparent from the description set forth below and the drawings, in which like reference characters identify correspondingly throughout and wherein:
FIG. 1 is a graphical representation of operating point verses power and current in a PV array for high and low irradiance circumstances.
FIG. 2 is a graphical representation of operating point at a fixed irradiance for varying cell temperatures
FIG. 3 is a graphical representation of operating point vs. power and current in a non-uniform-shading example of irradiance showing multiple peak power points.
FIG. 4 is a diagram of a large solar installation with varying MPP factors for different arrays and array groups.
FIG. 5A is a diagram of an example of a two-dimensional MPP space with inverters mapped and masters and slaves assigned according to a predetermined error margin.
FIG. 5B is a diagram of an example of a two-dimensional MPP-factor space, with inverters mapped and error margins plotted, showing an error-proofing algorithm in action to prevent inverters from inappropriately becoming slaves of other slaves.
FIGS. 6A-F are flow diagrams showing the control operation for sets of panels.
FIG. 6A (prior art) is a diagram of a representative building block for a large scale PV system.
FIG. 6B (prior art) is a diagram of a large PV system typical of conventional installations where MPPT functions are performed at each inverter.
FIG. 6C (prior art) is a diagram of representative building blocks for a large scale PV system capable of network communications.
FIG. 6D is a diagram of a large PV system with the addition of a data network that connects each inverter to each other and indicating that some inverters perform their own MPPT function while other inverters operate at the MPP point of another inverter. In this embodiment, the master/slave relationships can be assigned by any node on the network or by each inverter individually.
FIG. 6E is a diagram of a large PV system with the addition of a CCU (central control unit) added to the data network. In this embodiment, the CCU can make master/slave associations based on data from inverters.
FIG. 6F is a diagram of a large PV system where the CCU is making MPP decisions for each inverter.
FIG. 7 is a diagram indicating a typical flow diagram for a centrally controlled embodiment evaluating MPP factors and making master/slave assignments.
FIG. 8 is a diagram indicating a typical flow diagram for a self-directed embodiment where each inverter is evaluating MPP factors and making its own master/slave determination.
DETAILED DESCRIPTION
Overview
In a multi-inverter system, groups of arrays will often share similar internal and external factors that affect their MPP. The inverters are connected to a common communication network. Each inverter is capable of operating as a “master” that performs maximum power-point tracking (MPPT) for its own array, or as a “slave” that sets its operating point to match another inverter in the network. If only the master inverters need to perform MPPT when MPP factors change, while the slaves simply adjust their operating point to match their assigned masters, the total energy capture of the system will increase.
While a “common communication network” is described, it is understood that multiple networks within the meaning of the Open Systems Interconnection Basic Reference Model (OSI Model) at the OSI Network Layer and Transport Layer can be used. When connected through a device, such multiple networks can constitute a single “network” because control or communication is initiated at one device and received at another device. By way of example, a “common communication network” can include groups of inverters connected to separate networks that connect with a common CCU or networked group of CCUs.
In larger scale PV systems, on the order of 100's of kilowatts to 10's or 100's of megawatts, a large number of panels or arrays of panels are used covering very large ground surface areas. In some cases this could be on the order of 80,000 acres, by way of example. In these large systems, temperature-dependent losses in system components, such as wiring and transformers, also affect the MPP of the system. In these types of systems there are MPPT opportunities that cause the larger scale system to operate at or near its MPP using information from other PV systems in the local area. These large scale MPPT systems that rely on communication from adjacent PV systems have the ability to capture more energy than a large number of independently running MPPTs that operate independently from each other.
The control and peak power tracking of large scale PV plants using multiple arrays and inverters is accomplished by looking at the power levels of identified master arrays. Communication between the various arrays then allows for other arrays within the PV plant to track the master array.
Control of a power network having multiple power generating stations is achieved by use of maximum power-point (MPP) data or other power-related data. Power measurement factors from at least a subset of power stations in the power network are compared, and the data and comparison of the data is used to generate power measurement factor comparison data. The power measurement factor comparison data is used in tracking the data, for example by performing Maximum Power-Point Tracking (MPPT), with the MPPT based on the power measurement factor comparison data to provide. In the case of MPPT tracking, MPPT adjustments are made based on the MPPT data.
Maximum Power Point Adjustments
As mentioned, the Maximum Power Point (MPP) is the point on the IV curve which results in the maximum power. The MPP has a corresponding current and voltage. The inverter controls the bus voltage. In a perturb-and-observe algorithm (a reactive MPPT method), it adjusts the voltage, measures the output and repeats.
The described techniques adapt aspects of reference and other MPPT methods to large installations by taking advantage of the multiple inverters typical of large installations. The described techniques are particularly useful for large installations where the system is composed of tens or hundreds of inverters. In the described techniques, each inverter can operate as a “master” (reference) that uses an algorithm to track its own MPP, or as a “slave” that periodically adjusts its operating point to match its assigned master's. A wide variety of embodiments are feasible, differing from each other by (1) how inverters are selected to operate as masters or slaves, (2) which devices in the network perform the master/slave selection, (3) what data the selection is based on and how it is collected, and (4) how the selections are communicated to the affected inverters.
Selection of inverters to operate as masters or slaves can be done in several ways. Each master and its slaves can be manually selected by a user, or automatically selected by an algorithm. Selection criteria can include the relative physical location of the arrays in the system, the panels' ages or test results, or MPP factor data sensed in real time.
Connecting the multiple inverters through a network enables installation- wide mapping of MPP factors for each inverter's array at any given time. The mapping, combined with stored data, can identify groups of arrays that are “similarly situated” (i.e., subject to similar MPP factors). Within these groups, the “most average” member of the group can be identified and assigned to operate as a master until the MPP factors change. The mapping and use of the resulting information is an aspect that adds intelligence to the use of the existing MPPT methods. The “MPP factor space” in which the inverters are mapped can have as many dimensions as there are measured and stored MPP factors available: for instance, a very simple space could have one dimension, such as physical location or measured irradiance, or a complex MPP factor space could include many measured and stored factors. In MPP factor space, near- neighbor inverters are identified and their “distance” from each other compared to a pre-determined error margin. For example, if several inverters form a cluster in MPP-factor space, the inverter closest to the center may be selected as master, and the others within the error margin of the master may be selected as its slaves.
FIG. 5A is a diagram of an example of a simple two-dimensional MPP space with inverters mapped and masters and slaves assigned. Other MPP factors can also become dimensions in MPP-factor space. Such other MPP factors can include factors sensed in real time, or factors retrieved or calculated from stored data. Retrieved and calculated factors include panel batch characteristics, panel age, panel location, solar zenith and solar azimuth, all of which can become dimensions in MPP-factor space.
Depicted in FIG. 5A are a plurality of inverters, represented as 531 , 532 , 533 , 534 and 535 . By defining and plotting predetermined error margins around each inverter, e.g., 541 , 542 around inverters 531 , 532 , a model consistent with electrical performance of these network components can be generated and used. Alternatively, referring to the relative positions of the inverters 531 - 535 on the graphs of FIG. 5 , inverters 531 - 535 can be described in terms of space as defined by the axes of the graph. This space defined by the axes of the graph can be interpreted as MPP factor space. It is noted, that, while the error margins are shown here as dotted circles for simplicity, they may have any suitable shape. Typically, the error margins will often not be rotationally symmetric because each axis is a different MPP factor measured in different units, and the positive and negative error-margin widths may also be unequal.
Inverters 533 , 534 , and 535 are controlled as slaves to inverter 532 , which is the most centrally located of the group. Inverter 531 is an outlier, beyond the error margin of any of the inverters 532 , 533 , 534 , and 535 . Therefore it is assigned to operate independently of the other inverters as a master. Because no other inverters are within 531 's error margin 541 , inverter 531 is not assigned any slaves.
The algorithm may provide contingencies for scenarios where master/slave assignments might be unclear, as for example:
1. When a cluster spans more than one allowable error margin, grouping the inverters in a cluster so that the smallest number of inverters are masters and no slave follows another slave. 2. When a cluster spans more than one allowable error margin, reducing the error margin to more clearly isolate the inverter clusters. 3. Deciding which inverter is the master if none are clearly closest to the center of a group. 4. Periodically allowing each inverter to determine its own MPP to determine if significant shading exists. When shade is affecting one array, its MPP may be significantly different than another array even when all other MPP factors are identical. In this manner, the shade factor can be determined and added as a dimension in MPP factor space (shade may be affecting some arrays nearly equally, but significantly differently from others).
FIG. 5B is a diagram of an example of a simple two-dimensional MPP-factor space, with inverters 552 , 553 , 554 , 555 , 558 and 559 mapped and error margins plotted, illustrating these contingencies. Assume that inverter 553 functions as a master for inverters 552 , 554 , 555 and 558 . Inverter 559 is close enough to inverter 558 to be its slave. A contingency measure may be included in the algorithm to prevent this. Preventing 559 from slaving to 558 is advantageous because inverter 558 is already a slave to inverter 553 . Therefore, slaving 559 to 558 would effectively slave 559 to 553 , which would be inappropriate because 559 and 553 are outside each other's error margins. A similar contingency measure can be included in the algorithm to choose which inverter operates as the master when none of them are uniquely centered in a cluster—for example, when only two inverters lie within each other's error margin, both are equidistant from the center, but only one should be a master.
FIG. 5B also illustrates how an optional feature of the algorithm can examine alternative master/slave groupings to choose the arrangement that minimizes the number of masters, which may be one way to maximize plant-wide efficiency and power stability. For instance, in Grouping 1 (shown by the circles with shorter dashes), 553 could be assigned as master of 552 , 554 , 555 , and 558 (which lie within 553 's error margin); that would leave 559 (outside 553 's error margin) as a master with no slaves, therefore Grouping 1 would have 2 masters. Alternatively, in Grouping 2 (shown by the circles with longer dashes), inverter 558 could be assigned as master of 552 , 553 , and 559 (which lie within 558 's error margin). However, 554 and 555 are not within 558 's error margin, nor are they within each other's, so Grouping 2 would require that they both operate as masters, resulting in a total of 3 masters for Grouping 2 . Therefore, an algorithm capable of analyzing the choices and choosing the most advantageous under predetermined criteria can improve overall plant performance.
The selection of masters and slaves may be implemented anywhere on the network. A central control unit (CCU), such as a supervisory control and data acquisition (SCADA) system can select masters and slaves (“centrally controlled” embodiments). SCADA is only given as an example of central control, and it is possible to use different central control schemes and other non-central control schemes. Alternatively, processing components integrated in the inverters themselves may determine whether each inverter operates as a master or slave, independently of whether the network includes a CCU (“self-directed” embodiments).
The data to be applied to the networked-MPPT algorithms, which determine the selection of masters and slaves, can be collected in several ways. In a centrally controlled embodiment, a CCU may read MPP factors from inverters (e.g. present operating point & master/slave status), from array sensors (e.g., irradiance, temperature) or from storage (e.g. age, physical location). Some centrally-controlled or self-directed embodiments may use a CCU to collect the data and rebroadcast it to receiving components in the inverters; this is especially useful where several separate inverter networks communicate with the same CCU. In other self-directed embodiments, where all the inverters in a group of interest are connected by the same network, receiving components in the inverters may read the data sent to the CCU by other inverters and array sensors, and use it to make their own determination on whether to operate as masters or slaves. In still other self-directed embodiments, where all the inverters in a group of interest are connected by the same network, receiving components in the inverters may read MPP factor data broadcast by other inverters and array sensors onto the network whether or not the network includes a CCU.
Unlike prior-art reference MPPT systems, the assignment of masters and slaves need not be permanent. Master/slave assignments can be re-evaluated at regular intervals and changed if a change would be advantageous (result in higher energy capture). Alternatively, the re-evaluation may be event-driven: that is, a change in power output or sensed MPP factors may trigger a re-evaluation.
When a master/slave determination is made or changed for a given inverter, the implementation of that decision can be done in several ways. In a centrally-controlled embodiment, the CCU can issue a command to each inverter. In self-directed embodiments, processing components in the inverter can issue and carry out the commands, based on data collected through the CCU or directly from other inverters and array sensors in a “peer-to-peer” arrangement.
“Peer-to-peer” in this sense refers to how master/slave status and/or MPP factors can be communicated between inverters. The specific technique for communicating MPP and MPP factors depends on whether peer-to-peer or central control is used. Variations include:
1. Inverters make the master/slave decision (self-directed embodiment) and communicate their status and MPP factors to other inverters in a peer-to-peer manner. No CCU is needed; however, a CCU can optionally be used in this arrangement. 2. The CCU makes the master/slave decision in a centrally-controlled embodiment, but the actual control of MPP is effected by the designated masters. In this arrangement, the master inverters send their updated MPP to their slaves in a peer-to-peer manner.
Inverters operating as masters may perform MPPT by any suitable algorithm, including variations on predictive and reactive MPPT methods. Once a master has found its new MPP, its assigned slaves set their operating points to match the master's. To minimize fluctuations in power delivered to the grid, additional algorithms resident in either a CCU or on the individual inverters may provide for sequences and delays to ensure that only one, or a few, different master inverters are hunting for a new MPP (which involves varying the inverter's power output) at any given time and to stagger slave operating point changes.
FIGS. 6A-F are diagrams showing the control operation for sets of panels. FIG. 6A is a diagram of a representative building block for a large scale PV system. FIG. 6B is a diagram of a large PV system typical of conventional installations where MPPT functions are performed at each inverter. FIG. 6C is a diagram of representative building blocks for a large scale networked PV system. FIG. 6D is a diagram of a large PV system with the addition of a data network that connects each inverter to each other and indicating that some inverters perform their own MPPT function while other inverters operate at the MPP point of another inverter, and are assigned by any node on the network or by each inverter individually. FIG. 6E is a diagram of a large PV system with the addition of a CCU (central control unit) added to the data network, in which the CCU can make master/slave associations based on data from inverters. FIG. 6F is a diagram of a large PV system where the CCU is making MPP decisions for each inverter.
FIG. 6A is a simplified “building block” illustrating the basis for the more complex system diagrams to follow. The solid lines are power channels, and the dotted lines are communication channels. Power station 601 includes PV array 611 , DC power channel 612 , optional sensor 614 , sensor data channel 615 , and inverter 620 . Inverter 620 includes the inverter circuit module, which is identified as inverter switching function 621 , and a control module, identified as inverter MPPT function 623 . The inverter circuit module 621 provides an inverter output through power output channel 627 to substation 631 . PV array 611 delivers DC power through array power output channel 612 to inverter switching function 621 . Inverter 621 converts the array's DC power to AC power, which it delivers through inverter power output channel 627 to power substation 631 . Optionally, a sensor system 614 may measure external MPP factors affecting array 611 and send them through sensor data channel 615 to inverter MPPT function 623 (represented by a symbolic I-V curve). Array 611 , inverter switching function 621 , inverter MPPT function 623 , optional sensor 614 , and channels 612 , 615 that connect them together comprise power station 601 .
FIG. 6B demonstrates the prior art, in which each inverter performs MPPT independently for its own array; that is, every inverter acts as a master.
FIG. 6C is a simplified “building block” illustrating the basis for the more complex system diagrams to follow. The solid lines are power channels, and the dotted lines are communication channels. Power stations 641 , 642 each include PV array 611 , DC power channel 612 , optional sensor 614 , sensor data channel 615 , and inverter 645 . Inverter 645 includes the inverter circuit module, which is identified as inverter switching function 621 , and a control module, identified as inverter MPPT function 646 . Inverter 645 provides an inverter output through power output channel 627 to substation 631 . Additionally, the inverter control module is capable of interacting with other inverter control modules in different inverters 645 to permit control as a master (in power stations 641 ) or slave (in power stations 642 ). PV array 611 delivers DC power through array power output channel 612 to inverter switching function 621 . Inverter switching function 621 converts the array's DC power to AC power, which it delivers through inverter power output channel 627 to power substation 631 . Optionally, a sensor system 614 may measure external MPP factors affecting array 611 and send them through sensor data channel 615 to inverter MPPT function 646 . Array 611 , inverter switching function 621 , inverter MPPT function 646 , optional sensor 614 , and channels 612 and 615 that connect them together comprise power stations 641 , 642 .
The inverter can function a master, depicted as inverter 645 in power station 641 , or a slave, depicted as inverter 645 in power station 642 . Inverter 645 in power station 641 functioning as a master performs MPPT functions for that array, as determined by control module 646 . Inverter 645 in power station 642 functioning as a slave performs power point adjustments for that array as determined externally by a master (e.g., by control module 646 of inverter 645 in power station 641 ). Therefore, if the control module is in a slave mode, as represented at control module 646 a in power station 642 , that control module 646 a is responsive to an external control module. It is possible for a slave control module to have the capability to function as a master when no other suitable master is available.
FIG. 6D shows the general case, in which inverter MPPT functions interact (sending, receiving, or both) with generalized inverter communication network 649 . Power stations 641 and 642 on the data network have a master/slave assignment. Many variations on the nature of inverter communication network 649 , and on the information sent or received by inverter MPPT function 646 , are possible. Each of the following example approaches to networked MPPT (NMPPT) technique uses the networking of inverters to assign some of the inverters to operate as slaves to appropriate masters. Some may use the network to map the inverters in MPP-factor space, and use the map to choose the optimal number of masters. Several variations on this theme could be implemented:
Centrally Controlled NMPPT: A central control unit (CCU) 661 , which may be, by way of non-limiting example, a supervisory control and data acquisition (SCADA) system, is included. The CCU is part of the network and performs some of the functions. FIG. 6E illustrates a centrally controlled embodiment. The network can operate in either of the following ways:
a. Inverters send their measurements to the CCU, where other, non-measured MPP factors reside. The CCU periodically recalculates the MPP-factor map, assigns inverters to master or slave status, and sends a command to each slave inverter with its new commanded operating point. b. Same as a. above (inverters send their measurements to the CCU), except the inverters can read each other's operating point through the network, so slaves can follow their masters through multiple MPPT cycles until the CCU assigns them to different masters or commands them to become masters.
In centrally-controlled embodiments where a CCU is present, the CCU itself may perform maximum power point tracking for specific inverters or for the system as a whole and communicate commanded operating points to each inverter. In this example, all inverters are slaves of the CCU.
FIG. 6F shows an alternate embodiment where CCU 671 includes an internal MPPT function and the inverters are, in effect, slaved to the CCU. The MPPT resides in CCU 671 (represented by a symbolic I-V curve), and all inverters “slave” to CCU 671 , based on the internal MPPT function. The CCU may determine, as shown here, a single MPP for all the inverters; alternatively, it may determine a set of MPPs for each inverter separately or for multiple subgroups of inverters.
Self-Directed NMPPT: Inverters analyze their own MPP factors and those of other inverters to make their own master/slave decisions.
a. Inverters send their measurements to the CCU, but the CCU only rebroadcasts the measurements to all the inverters, appending any non-measured MPP factors. Each inverter analyzes the positions of its neighbors in MPP factor space and makes its own decision whether to function as a master or a slave. The CCU rebroadcast is useful when not all the inverters are on the same network. b. Inverters connected as in FIG. 6E send their measurements and non-measured MPP factors to the CCU while reading what all (or some) of the other inverters are sending. Inverters make their own master/slave decisions based on their readings. The CCU only monitors the data for use in performance evaluation or sending maintenance alerts. c. The CCU does not participate in the NMPPT process and need not even be part of the network (as in a literal, rather than symbolic, interpretation of the network in FIG. 6D ). Inverters broadcast their measurements and non-measured MPP factors to each other and make their own master/slave decisions.
Control Configurations
FIGS. 7 and 8 are example control configurations for a plurality of arrays.
FIG. 7 is a flowchart of an example algorithm for a centrally-controlled configuration, showing the process that can take place in the CCU. This configuration is an example of an algorithm in which a CCU maps MPP-factor space and commands slaves to set their operating points based on MPP data read from assigned masters. Appropriate master/slave assignments are sorted by the algorithm to ensure that masters and slaves are of similar age and are similarly situated geographically, as well as having similar real-time measured MPP factors (MPP factor space mapping).
Information 711 - 713 regarding MPP factors is obtained. The information includes information 711 in the form of a lookup table regarding acceptable geographic master/slave groupings, information 712 in the form of a lookup table regarding acceptable panel-age-based master/slave groupings, and real-time measured MPP factors 713 for all inverters, including information from sensors. The sensors may be optical sensors, thermal sensors, and other types of sensors. The information is used to map MPP-factor space and assign masters & slaves (step 721 ). Commands are then issued (step 722 ) to the slaves and masters, in which the slaves stop MPPT and the masters begin or resume MPPT. New MPP operating points are gathered from the masters (step 723 ). The operating points from the masters are then sent to the slaves (step 724 ) and the slaves operated at those operating points. In any of these configurations, any suitable MPPT method may be used by the assigned master inverters or the CCU, including the presently known methods of predictive, reactive and reference MPPT.
The process is repeated at fixed intervals (step 731 ).
FIG. 8 is a flowchart of an example algorithm for a self-directed configuration, showing a process that can take place within each inverter. In any of these configurations, any suitable MPPT method may be used by the assigned master inverters or the CCU, including the presently known methods of predictive, reactive and reference MPPT.
Information 811 - 814 regarding MPP factors is obtained. The information includes information 811 in the form of a lookup table regarding geographical neighbor inverters, information 812 in the form of a lookup table regarding panel age of neighbor inverters, the subject inverter's real-time MPP factors 813 and other inverters' real-time factors 814 . The information is used to compare (step 821 ) the subject inverter's MPP factors with MPP factors of its neighbors. The particular neighbor having MPP factors closest to those of the subject inverter is identified (step 822 ) and a determination (step 823 ) is made of whether the MPP factors of the closest neighbor is within an error margin.
In the case of the MPP factors of the closest neighbor is within the error margin, the neighbor is made the temporary preferred master (TPM, step 824 ) and a determination (step 831 ) is made as to whether a TPM was found. In the case of MPP factors of the closest neighbor not being within the error margin, or in the case of there being no TPM, the subject inverter is set as the master and a master flag is set to “Master” (step 832 ).
If a TPM exists (determination step 831 ), a determination is made whether the inverter is already a master (existing status flag is already set to “Master”, step 841 ), and if not, a determination (step 843 ) is made whether the subject inverter is slaved to the TPM. If the subject inverter is not slaved to the TPM, the status flag of the subject inverter is set to “Slave” and the master is the TPM. In either case, meaning the subject inverter is slaved to TPM (determination 843 ) or the status flag is already set to “Slave” (step 841 , 3 ), the result is the same, meaning the subject inverter is slaved to the TPM and the status flag set to “Slave”. A match is made (step 851 ) of the TPM's operating point, and a self-reference check (to prevent multiple inverters from slaving to each other) is performed (step 852 ). A determination (step 853 ) is made of whether the self reference check passed.
In the case of the self reference check not passing (determination 853 ) a determination (step 855 ) is made of whether the subject inverter's ID is greater than the TPM ID. If the subject inverter's ID is greater than the TPM ID (determination 855 ), then the subject inverter is slaved to the TPM until the next repeat of the sequence. The determination of whether the subject inverter's ID is greater than the TPM ID is a very basic self reference algorithm. This sequence is given as an example of a self-reference algorithm, and is not intended to exclude other techniques.
If the subject inverter's ID is not greater than the TPM ID (determination 855 ), then the status flag is set to master (step 832 ).
In the case of the status flag already being set to “Master” as determined at determination 841 , a determination (step 871 ) is made of whether there are any current slaves, and if not, the inverter is allowed to slave to the TPM (step 845 ). If the determination (at step 871 ) is that there are current slaves, MPPT is performed (step 873 ) and the subject inverter is operated as a Master until the next repeat of the sequence.
MPPT is also performed (step 873 ) in response to setting of the master flag to “Master” (step 832 ).
The process repeats at fixed intervals (step 881 ) by returning to the comparing of the subject inverter's MPP factors with MPP factors of its neighbors at step 821 .
These possible, but not essential, enhancements can work with several variations, non-limiting examples being:
Predictive operation: Extra storage and analysis capability is added to either the CCU or the inverters so they can use MPP-factor map history to predict what will happen next, reducing lag time between MPP changes and inverter voltage corrections. For instance, a moving cloud will cause a traveling ripple in irradiance across adjacent arrays. The speed and direction of the ripple can be measured, and the next arrays in the path will adjust for it as (instead of after) it reaches them.
Predictive MPPT approaches set the operating point of the PV array based on a predetermined constant value or based on an algorithm that adjusts the operating point based on inputs such as time of day, actual or predicted irradiance levels, or actual or predicted cell temperature. One predictive MPPT approach is the “optimized fixed voltage” method, where each panel or array is operated at the fixed operating point that will stay nearest the MPP over the course of an “average day”; the fixed operating point can be determined by models or sets of previous measurements. Another predictive MPPT approach is voltage scheduling, where a timer changes the array operating point by increments based on expected MPP changes as time goes by. Advanced voltage-scheduling algorithms can account for cell age as well as expected daily and seasonal irradiance and temperature changes.
Peer-to-peer communication: While master/slave relationships last, masters communicate their MPP changes and MPP factors directly to all their slaves, speeding up responses and simplifying processing. Slaves periodically monitor the general MPP-factor traffic and decide whether to become slaves to another master or become masters themselves.
Manual overrides:
a. An operator can assign some inverters to always be masters, and the rest to be slaves to whichever master is closest in MPP space. b. An operator can prevent inverters from becoming slaves to certain other inverters (for instance, those geographically too far away, or pointing at a different angle, or still being “burned in” after installation.). A “No Follow Flag” may be used in order to keep other inverters from slaving to an inappropriate master. c. An operator can assign a sequence or delay between masters performing MPPT so that only one or a few masters are doing so at any given time. This confines the power fluctuations associated with the MPPT process to a small fraction of the total power produced by the installation at any given time.
Automatic Override by Inverter: It is possible to permit the inverter to override the CCU in instances where a MPP factor exceeds a predetermined threshold. In centrally controlled embodiments, where a master is performing MPPT on its respective array, but the polling frequency from the CCU is such that the inverter may perform several MPPT operations between CCU polls, the inverter can initiate a message to the CCU if a deadband threshold is exceeded between MPPT operations. In such instances, the CCU could initiate recalculation of MPP factor space. By way of example, if the deadband threshold is exceeded from one MPPT operation to another to initiate recalculation of MPP factor space and/or immediately direct slaves to begin operating as their own masters.
Software Implementation
The operation and control features can be implemented in hardware, software or a combination of hardware and software. In the case of software, the software may be embodied in storage media or as firmware. Storage media and computer readable media for containing code, or portions of code, can include any appropriate media known or used in the art, including storage media and communication media, such as but not limited to volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage and/or transmission of information such as computer readable instructions, data structures, program modules, or other data, including RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, data signals, data transmissions, or any other medium which can be used to store or transmit the desired information and which can be accessed by the computer. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will appreciate other ways and/or methods to implement the various embodiments.
Conclusion
It will be understood that many additional changes in the details, materials, steps and arrangement of parts, which have been herein described and illustrated to explain the nature of the described technique, may be made by those skilled in the art within the principal and scope of the invention as expressed in the appended claims.
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A group of solar power stations with inverters are adjusted in order to achieve optimum power output in accordance with maximum power-point tracking (MPPT). The MPPT data is used to perform adjustments. Power measurement factors, including Maximum Power Points (MPPs) are established to represent a bus-voltage setting that produces the maximum power output from an individual photovoltaic panel. These settings are established for the group so as to optimize power output under a variety of operating conditions.
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TECHNICAL FIELD
The present embodiments relate generally to communication devices, and specifically to amplifiers within communication devices that may amplify a signal while reducing harmonic distortion.
BACKGROUND OF RELATED ART
Communication devices may transmit and receive communication data through a communication medium. In one example, the communication medium may be a wireless communication medium where communication data is transmitted and received by communication devices according to a wireless communication protocol. Example wireless communication protocols may include IEEE 802.11 protocols and Bluetooth protocols according to the Bluetooth Special Interest Group. In another example, the communication medium may be a wired communication medium where the communication data is transmitted and received according to a wire-based communication protocol. Some example wire-based protocols may include an Ethernet® protocol and/or a Powerline Communications protocol described by the HomePlug 2.0 specification. In yet another example, the communication medium may be a hybrid combination of wired and wireless communication mediums.
Analog signals within communication devices may undergo amplification during various processing operations. For example, an analog signal may be amplified when a communication signal is received from or transmitted to another communication device. In some cases, as an analog signal is amplified, an unwanted signal may be introduced (e.g., added) to the amplified signal. For example, as a first signal is amplified, a second signal that is an unwanted harmonic of the first signal may also be amplified. The unwanted signal may distort the amplified signal, reducing the accuracy of the amplified signal and increasing the difficulty of receiving the amplified signal and decoding the data within the amplified signal. In some cases, the unwanted signal may couple into a sensitive receive and/or transmit circuit and interfere with the transmission and/or reception of the communication data.
Thus, there is a need to improve the amplification of analog signals while suppressing amplification of unwanted signals, and thereby improve the performance of the communication device.
SUMMARY
This Summary is provided to introduce in a simplified form a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.
A configurable amplifier and method of operation are disclosed. The configurable amplifier may amplify a communication signal while cancelling or attenuating a second harmonic component of the communication signal. In one embodiment, the configurable amplifier may include a first processing chain to generate a first up-converted communication signal, a second processing chain to generate a second up-converted communication signal, and a summing node to generate an output signal of the configurable amplifier based, at least in part, on the first up-converted communication signal and the second up-converted communication signal. When the configurable amplifier is to operate in a first mode, the second up-converted communication signal is a substantially ninety degree phase-shifted version of the first up-converted communication signal. When the configurable amplifier is to operate in a second mode, the second up-converted communication signal is substantially similar to the first up-converted communication signal.
A wireless communication device is disclosed. The wireless communication device may include a baseband processor and a configurable amplifier, coupled to the baseband processor, to amplify communication signals, the configurable amplifier including: a first processing chain to generate a first up-converted communication signal, a second processing chain to generate a second up-converted communication signal, and a summing node to generate an output signal of the configurable amplifier based, at least in part, on the first up-converted communication signal and the second up-converted communication signal. When the configurable amplifier is to operate in a first mode, the second up-converted communication signal is a substantially ninety degree phase-shifted version of the first up-converted communication signal. When the configurable amplifier is to operate in a second mode, the second up-converted communication signal is substantially similar to the first up-converted communication signal.
BRIEF DESCRIPTION OF THE DRAWINGS
The present embodiments are illustrated by way of example and are not intended to be limited by the figures of the accompanying drawings. Like numbers reference like elements throughout the drawings and specification.
FIG. 1 depicts an example communication system within which example embodiments may be implemented.
FIG. 2 shows a schematic diagram of a configurable amplifier, in accordance with example embodiments.
FIG. 3 is a block diagram of a mode controller, in accordance with example embodiments.
FIG. 4 shows a wireless device that is one embodiment of a wireless device of FIG. 1 .
FIG. 5 shows an illustrative flow chart depicting an exemplary operation for operating a configurable amplifier, in accordance with example embodiments.
DETAILED DESCRIPTION
The present embodiments are described below in the context of Wi-Fi enabled devices for simplicity only. It is to be understood that the present embodiments are equally applicable for devices using signals of other various wireless standards or protocols. As used herein, the terms “wireless local area network (WLAN)” and “Wi-Fi” can include communications governed by the IEEE 802.11 standards, BLUETOOTH®, HiperLAN (a set of wireless standards, comparable to the IEEE 802.11 standards, used primarily in Europe), and other technologies used in wireless communications (e.g., ZigBee and WiGig).
In the following description, numerous specific details are set forth such as examples of specific components, circuits, and processes to provide a thorough understanding of the present disclosure. The term “coupled” as used herein means coupled directly to or coupled through one or more intervening components or circuits. Also, in the following description and for purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the present embodiments. However, it will be apparent to one skilled in the art that these specific details may not be required to practice the present embodiments. In other instances, well-known circuits and devices are shown in block diagram form to avoid obscuring the present disclosure. Any of the signals provided over various buses described herein may be time-multiplexed with other signals and provided over one or more common buses. Additionally, the interconnection between circuit elements or software blocks may be shown as buses or as single signal lines. Each of the buses may alternatively be a single signal line, and each of the single signal lines may alternatively be buses, and a single line or bus might represent any one or more of a myriad of physical or logical mechanisms for communication between components. The present embodiments are not to be construed as limited to specific examples described herein but rather to include within their scope all embodiments defined by the appended claims.
FIG. 1 depicts an example communication system 100 within which example embodiments may be implemented. Communication system 100 may be a wireless system and may include wireless device 102 and wireless device 103 . Although only two wireless devices 102 and 103 are shown for simplicity, communication system 100 may include any number of wireless devices. In other embodiments, communication system 100 may be a wired system and may include wired devices coupled to a wire or cable (not shown for simplicity). In still other embodiments, communication system 100 may be a hybrid system and may include both wireless and wired devices.
Wireless device 102 may include a transceiver 120 , a baseband processor 110 , and an antenna 160 . Although not shown for simplicity, wireless device 102 may include a plurality of antennas. Baseband processor 110 may provide data to be transmitted to and/or receive data from one or more other devices via transceiver 120 and antenna 160 . For example, baseband processor 110 may encode and/or decode the communication data for transmission and/or reception by transceiver 120 .
Transceiver 120 may include a digital processor 140 and an analog processor 130 . Digital processor 140 may receive the communication data from and provide the communication data to baseband processor 110 . In some embodiments, the communication data may be processed according to a wireless communication protocol such as Wi-Fi, BLUETOOTH, near-field communication, Zig-Bee, or any other feasible wireless communication protocol. In other embodiments, the communication data may be processed according to a wired protocol such as an Ethernet, Powerline Communication (PLC), or any other feasible wired communication protocol. In still other embodiments, the communication data may be processed according to both a wireless and a wired communication protocol.
In some embodiments, analog processor 130 may be coupled to digital processor 140 and to antenna 160 . Analog processor 130 may process communication data to and/or from digital processor 140 . For example, analog processor 130 may process communication data from digital processor 140 for transmission through antenna 160 and/or analog processor 130 may process and provide communication data received through antenna 160 to digital processor 140 .
Analog processor 130 may include a configurable amplifier 135 to amplify one or more communication signals. For example, configurable amplifier 135 may amplify a communication signal received through antenna 160 . In another example, configurable amplifier 135 may amplify a communication signal to be transmitted from antenna 160 . In some embodiments, configurable amplifier 135 may amplify the communication signal while suppressing unwanted harmonics of the communication signal. Operation of configurable amplifier 135 is described in more detail below in conjunction with FIG. 2 .
Persons skilled in the art will recognize that an output signal of an amplifier, such as configurable amplifier 135 , may be described with a power series of the form shown in eq. 1 below:
Output= gm 1( S 1)cos θ+ gm 2( S 1) 2 cos 2 θ+gm 3( S 1) 3 cos 3 θ+ . . . (eq. 1)
where: gm(S1)cos θ is a first harmonic of the output signal (e.g., desired signal);
gm2(S1) 2 cos 2 θ is a second harmonic of the output signal; gm3(S1) 3 cos 3 θ is a third harmonic of the output signal, and so forth.
The term “gm” may represent a gain of the amplifier associated with the first harmonic, the term “gm2” may represent a gain of the amplifier associated with the second harmonic, and so forth. The input signal to the amplifier may be represented by the term “(S1)cos θ”.
In some embodiments, to reduce effects associated with the second harmonic component (e.g., the second harmonic of the output signal), the output signal may be based on the input signal (S1)cos θ and a version of the input signal shifted by ninety (90) degrees (e.g., (S1)sin θ). Eq. 1 may be rewritten to express the output signal as a function of the input signal (S1)cos θ (e.g., original input signal) and (S1)sin θ (e.g., original input signal shifted by ninety degrees) as shown in eq. 2, below (note: eq. 2 is simplified to only include first and second harmonic terms):
Output= gm 1( S 1)cos θ+ gm 2( S 1) 2 cos 2 θ+gm 1( S 1)sin θ+ gm 2( S 1) 2 sin 2 θ (eq. 2)
Eq. 2 may be rewritten to combine the first harmonic and the second harmonic terms as shown below in eq. 3:
Output= gm 1( S 1)cos θ+ gm 1( S 1)sin θ+ gm 2( S 1) 2 cos 2 θ+gm 2( S 1) 2 sin 2 θ (eq. 3)
Simplifying eq. 3 gives:
Output= gm 1( S 1)(cos θ+sin θ)+ gm 2( S 1) 2 (eq. 4)
where: gm1(S1)(cos θ+sin θ) is associated with the first harmonic, and
gm2(S1) 2 is associated with the second harmonic.
Note that the term associated with the second harmonic component has been simplified to a constant, and thus is no longer dependent on frequency. In other words, signals associated with a second harmonic distortion may be cancelled or substantially reduced when the input signal and a ninety degree shifted version of the input signal are processed at substantially the same time by the amplifier. Note also that the term associated with the first harmonic component has changed from “gm1(S1)cos θ” to “gm1(S1)(cos θ+sin θ),” for example, to indicate a change in the amplitude of the first harmonic component.
FIG. 2 shows a schematic diagram of a configurable amplifier 200 , in accordance with example embodiments. Configurable amplifier 200 may be another embodiment of configurable amplifier 135 of FIG. 1 . Configurable amplifier 200 may include a first processing path P 1 and a second processing path P 2 . First processing path P 1 may include a first mixer 210 , a second mixer 215 , a first buffer 230 , a first summing node 217 , and a first transistor pair 260 . Second processing path P 2 may include a third mixer 220 , a fourth mixer 225 , a first local oscillator (LO) signal selector 245 , a second LO signal selector 246 , a second buffer 235 , a second summing node 227 , and a second transistor pair 261 . The first transistor pair 260 may be coupled to the second transistor pair 261 at a third summing node 241 .
First processing path P 1 may generate a first up-converted communication signal 274 and second processing path P 2 may generate a second up-converted communication signal 276 . Third summing node 241 may sum together first up-converted communication signal 274 and second up-converted communication signal 276 to generate a configurable amplifier output signal 275 .
Configurable amplifier 200 may operate in a normal mode or in a cancelling mode. When configurable amplifier 200 operates in the normal mode, second up-converted communication signal 276 may be substantially similar to first up-converted communication signal 274 . Thus, when configurable amplifier 200 operates in the normal mode, third summing node 241 may sum together first up-converted communication signal 274 and second up-converted communication signal 276 (substantially similar to the first up-converted communication signal 274 ) to generate configurable amplifier output signal 275 .
When configurable amplifier 200 operates in the cancelling mode, second processing path P 2 may generate second up-converted communication signal 276 to be a ninety degree phase-shifted version of first up-converted communication signal 274 generated by first processing path P 1 . Thus, when configurable amplifier 200 operates in the cancelling mode, third summing node 241 may sum together first up-converted communication signal 274 and a ninety degree phase-shifted version of first up-converted communication signal 276 . The resulting summed signal, denoted as configurable amplifier output signal 275 , may have a cancelled or reduced second harmonic distortion (based, at least in part, on eq. 4).
Thus, as described in more detail below, when configurable amplifier 200 operates in the cancelling mode, the second up-converted communication signal 276 may cancel at least second-order harmonics of the configurable amplifier output signal 275 ; when configurable amplifier 200 operates in the normal mode, the second up-converted communication signal 276 may increase the magnitude of the configurable amplifier output signal 275 (e.g., as compared to the output signal magnitude when configurable amplifier 200 operates in the cancelling mode).
First processing path P 1 may mix together an LO signal and a baseband signal. In some embodiments, the LO signal and the baseband signal may be quadrature signals. For example, the LO signal may include an LO in-phase (I) signal 201 and an LO quadrature (Q) signal 203 . In a similar manner, the baseband signal may include a baseband in-phase (I) signal 202 and a baseband quadrature (Q) signal 204 . First mixer 210 may “mix” (e.g., multiply) together LO (I) signal 201 and baseband (I) signal 202 to generate a first mixer output signal that may be provided to first summing node 217 . In a similar manner, second mixer 215 may mix together LO (Q) signal 203 and baseband (Q) signal 204 to generate a second mixer output signal that may be provided to first summing node 217 . Output signals from first mixer 210 and second mixer 215 may be summed together at first summing node 217 , and the resulting summed signal may be provided to first buffer 230 .
First buffer 230 may be coupled to first transistor pair 260 . First transistor pair 260 may amplify and/or buffer output signals from first buffer 230 . First transistor pair 260 may include a first transistor Q 1 and a second transistor Q 2 configured as a cascode pair. In some embodiments, second transistor Q 2 may include a gate terminal coupled to a bias voltage VB 1 . A gate terminal of first transistor Q 1 may receive the output signal provided by first buffer 230 , and a drain terminal of second transistor Q 2 may provide an output signal (e.g., first up-converted communication signal 274 ) from first transistor pair 260 to third summing node 241 .
Third summing node 241 may be coupled to output inductor 242 . Output inductor 242 may receive configurable amplifier output signal 275 from third summing node 241 , and output inductor 242 may be coupled to other circuits or devices (not shown for simplicity). For example, output inductor 242 may be coupled to an antenna, a balun, a coupler, or any other technically feasible device. Thus, in some embodiments, configurable amplifier output signal 275 may be provided to other circuits or devices through output inductor 242 .
Although depicted with NMOS transistors, other embodiments of first transistor pair 260 may include any other technically feasible transistor types. For example, first transistor Q 1 and/or second transistor Q 2 may be a PMOS, an NPN, and/or a PNP transistor (not shown for simplicity). In still other embodiments, first transistor pair 260 may be replaced with other devices to amplify and/or buffer output signals from first buffer 230 or first summing node 217 . For example, first transistor pair 260 may be replaced with an inverting amplifier, a voltage buffer, a current buffer, an operational amplifier, or any other technically feasible amplifier.
In a similar manner, when configurable amplifier 200 operates in the normal mode, second processing path P 2 may also mix together the baseband signal and the LO signal. For example, LO (I) signal 201 may be selected by first LO signal selector 245 and provided to third mixer 220 . First LO signal selector 245 may include switches, transistors, multiplexors, and/or any other technically feasible devices and/or components to select signals, such as LO (I) signal 201 . Third mixer 220 may mix together LO (I) signal 201 and baseband (I) signal 202 and provide a third mixer output signal to second summing node 227 . LO (Q) signal 203 may be selected by second LO signal selector 246 and provided to fourth mixer 225 . Fourth mixer 225 may mix together LO (Q) signal 203 and baseband (Q) signal 204 and provide a fourth mixer output signal to second summing node 227 . Output signals from third mixer 220 and fourth mixer 225 may be summed together at second summing node 227 , and the resulting summed signal may be coupled to second buffer 235 .
Second buffer 235 may be coupled to second transistor pair 261 . Second transistor pair 261 may amplify and/or buffer output signals from second buffer 235 . Second transistor pair 261 may include a third transistor Q 3 and a fourth transistor Q 4 configured as a cascode pair. In some embodiments, fourth transistor Q 4 may include a gate terminal coupled to a bias voltage VB 2 . A gate terminal of third transistor Q 3 may receive the output signal from second buffer 235 , and a drain terminal of fourth transistor Q 4 may provide an output signal (e.g., second up-converted communication signal 276 ) from second transistor pair 261 to third summing node 241 .
Second up-converted communication signal 276 from second transistor pair 261 may be coupled to third summing node 241 . Thus, third summing node 241 may sum together first up-converted communication signal 274 and second up-converted communication signal 276 , thereby summing together output signals from first processing path P 1 and second processing path P 2 .
When configurable amplifier 200 operates in the normal mode, first processing path P 1 and second processing path P 2 may each generate a substantially similar signal that may be summed together at third summing node 241 . For example, the LO signal (including both in-phase and quadrature components) may be expressed by eq., 5 shown below:
LO signal=cos α−sin α (eq. 5)
where: −sin α is associated with LO (I) signal 201 ; and
cos α is associated with LO (Q) signal 203 .
Thus, the quadrature relationship between LO (I) signal 201 and LO (Q) signal 203 may be expressed by cosine and sine terms in eq. 5. In a similar manner, the baseband signal may be expressed by eq. 6, shown below:
baseband signal=sin β+cos β (eq. 6)
where: sin β is associated with baseband (I) signal 202 ; and
cos β is associated with baseband (Q) signal 204 .
Thus, the quadrature relationship between baseband (I) signal 202 and baseband (Q) signal 204 may be described by sine and cosine terms in eq. 6.
An output signal from first processing path P 1 may be expressed by eq. 7 shown below:
output signal P 1=cos α cos β−sin α sin β (eq. 7)
where: cos α cos β is associated with mixing LO (Q) signal 203 together with baseband (Q) signal 204 ; and
sin α sin β is associated with mixing LO (I) signal 201 together with baseband (I) signal 202 .
When configurable amplifier 200 operates in the normal mode, first up-converted communication signal 274 and second up-converted communication signal 276 are substantially similar. Since configurable amplifier output signal 275 may be based on a sum of similar output signals from first processing path P 1 and second processing path P 2 , the configurable amplifier output signal 275 may be expressed by eq. 8, shown below:
configurable amplifier output signal 275=2(cos α cos β−sin α sin β) (eq. 8)
Thus, because the first up-converted communication signal 274 and the second up-converted communication signal 276 are substantially similar and are summed at third summing node 241 , the magnitude of the configurable amplifier output signal 275 may be increased relative to the output signal magnitude when configurable amplifier 200 operates in the cancelling mode.
As described above in conjunction with eq. 4, a second harmonic component of an output signal may be reduced or canceled by adding together a first signal and a ninety degree phase-shifted version of the first signal. Thus, when configurable amplifier 200 operates in the cancelling mode, second processing path P 2 may be configured to generate second up-converted communication signal 276 to be a ninety degree phase-shifted version of first up-converted communication signal 274 provided by first processing path P 1 . In some embodiments, the LO signal used in second processing path P 2 may be phase-shifted by ninety degrees with respect to the LO signal used in first processing path P 1 . For example, LO (I) signal 201 may be replaced with LO_shifted (I) signal 205 , and LO (Q) signal 203 may be replaced with LO_shifted (Q) signal 206 . In some embodiments, LO_shifted (I) signal 205 and LO_shifted (Q) signal 206 may be ninety degree phase-shifted versions of LO (I) signal 201 and LO (Q) signal 203 , respectively. The phase-shifted LO signal may cause the output signal from second processing path P 2 to be a phase-shifted version of the output signal from first processing path P 1 .
When configurable amplifier 200 operates in the cancelling mode, second processing path P 2 may mix together the baseband signal and the shifted LO signal. For example, LO_shifted (I) signal 205 may be selected by first LO signal selector 245 and provided to third mixer 220 . Third mixer 220 may mix together LO_shifted (I) signal 205 and baseband (I) signal 202 and provide the third mixer output signal to second summing node 227 . LO_shifted (Q) signal 206 may be selected by second LO signal selector 246 and provided to fourth mixer 225 . Fourth mixer 225 may mix together LO_shifted (Q) signal 206 and baseband (Q) signal 204 and provide the fourth mixer output signal to second summing node 227 . Output signals from third mixer 220 and fourth mixer 225 may be summed together at second summing node 227 and the resulting summed signal provided to second buffer 235 .
The first up-converted communication signal 274 output from first transistor pair 260 and the second up-converted communication signal 276 output from second transistor pair 261 may be summed together at third summing node 241 . Referring back to eq. 5, a ninety degree phase-shifted LO signal may be expressed by eq. 9, shown below:
LO_shifted signal=sin α+cos α (eq. 9)
where: cos α is associated with LO_shifted (I) signal 205 ; and
sin α is associated with LO_shifted (Q) signal 206 .
Baseband signal may still be expressed by eq. 6. When configurable amplifier 200 operates in the cancelling mode, second processing path P 2 may generate an output signal described by eq. 10 shown below:
output signal P 2=sin α cos β−cos α sin β (eq. 10)
where: sin α cos β is associated with mixing LO_shifted (Q) signal 206 together with baseband (Q) signal 204 ; and
cos α sin β is associated with mixing LO_shifted (I) signal 205 together with baseband (I) signal 202 .
The output signal for first processing path P 1 (eq. 7) may be rewritten as:
cos(α+β)=cos α cos β−sin α sin β (eq. 11)
In a similar manner, the output signal for second processing path P 2 (eq. 10) may be rewritten as:
sin(α+β)=sin α cos β+cos α sin β) (eq. 12)
Thus, configurable amplifier output signal 275 may be expressed by eq. 13 below:
configurable amplifier output signal 275=sin(α+β)+cos(α+β) (eq. 13)
In other words, when configurable amplifier 200 operates in the cancelling mode, configurable amplifier output signal 275 is based, at least in part, on a first signal (e.g., sin(α+β)) and a ninety degree phase-shifted version of the first signal (e.g., cos(α+β)). Thus, configurable amplifier output signal 275 may have a reduced or cancelled second harmonic component.
FIG. 3 is a block diagram of a mode controller 300 , in accordance with example embodiments. Mode controller 300 may include a control block 310 and a signal generator 320 . Control block 310 may drive a mode control signal 315 to a state that may cause configurable amplifier 200 to operate in the normal operating mode or the cancelling mode, as described above. In some embodiments, control block 310 may drive mode control signal 315 to a first state that may cause configurable amplifier 200 to operate in the normal operating mode when little or no cancelling of the second harmonic component of configurable amplifier output signal 275 is desired. Control block 310 may drive mode control signal 315 to a second state that may cause configurable amplifier 200 to operate in the cancelling mode when a cancelling or reduction of the second harmonic component of configurable amplifier output signal 275 is desired. For example, based on a characteristic frequency of an input signal for configurable amplifier 200 , a second harmonic component of configurable amplifier output signal 275 may interfere with one or more devices and/or circuits within wireless device 102 . Thus, configurable amplifier 200 may be operated in cancelling mode to reduce or cancel the second harmonic component and reduce any associated interference.
Signal generator 320 may receive mode control signal 315 and, in response thereto, may generate LO select signal 240 . For example, in some embodiments, when configurable amplifier 200 operates in the normal mode, LO select signal 240 may not be asserted and/or be at a low logic level (or a first logical state) to enable first LO signal selector 245 and second LO signal selector 246 to select LO (I) signal 201 and LO (Q) signal 203 , respectively. When configurable amplifier 200 operates in the cancelling mode, LO select signal 240 may be asserted and/or be at a high logic level (or a second logical state) to enable first LO signal selector 245 and second LO signal selector 246 to select LO_shifted (I) signal 205 and LO_shifted (Q) signal 206 , respectively.
FIG. 4 shows a wireless device 400 that is one embodiment of wireless device 102 and/or 103 of FIG. 1 . Wireless device 400 includes a transceiver 410 , a processor 430 , a memory 440 , and one or more antennas 450 . Transceiver 410 may transmit and receive communication signals. Transceiver 410 may include configurable amplifier 420 to amplify communication signals associated with transceiver 410 . For some embodiments, configurable amplifier 420 may another embodiment of configurable amplifier 135 of FIG. 1 and/or configurable amplifier 200 of FIG. 2 .
Memory 440 may include a non-transitory computer-readable storage medium (e.g., one or more nonvolatile memory elements, such as EPROM, EEPROM, Flash memory, a hard drive, etc.) that may store the following software modules:
transceiver control module 442 to control transceiver 410 to transmit and receive communication signals in accordance with one or more communication protocols; and configurable amplifier control module 444 to control configurable amplifier 420 to amplify one or more communication signals within transceiver 410 .
Each software module includes program instructions that, when executed by processor 430 , may cause the wireless device 400 to perform the corresponding function(s). Thus, the non-transitory computer-readable storage medium of memory 440 may include instructions for performing all or a portion of the operations of FIG. 5 .
Processor 430 , which is coupled transceiver 410 and memory 440 , may be any one or more suitable processors capable of executing scripts or instructions of one or more software programs stored in the wireless device 400 (e.g., within memory 440 ).
Processor 430 may execute transceiver control module 442 to configure transceiver 410 to receive and/or transmit communication signals in accordance with a communication protocol. In some embodiments, transceiver control module 442 may determine an operating frequency (e.g., carrier frequency) for transceiver 410 .
Processor 430 may execute configurable amplifier control module 444 to select an operating mode for configurable amplifier 420 . For example, based on a selected operating frequency used by transceiver 410 , configurable amplifier control module 444 may determine an operating mode for configurable amplifier 420 . In some embodiments, when a second harmonic frequency of a signal amplified by configurable amplifier 420 may interfere with another component and/or circuit within wireless device 400 , then configurable amplifier control module 444 may operate configurable amplifier 420 in the cancelling mode. Conversely, when the second harmonic frequency of the signal amplified by configurable amplifier 420 may not interfere with another component and/or circuit within wireless device 400 , then configurable amplifier control module 444 may operate configurable amplifier 420 in the normal mode.
FIG. 5 shows an illustrative flow chart depicting an exemplary operation 500 for operating configurable amplifier 420 , in accordance with example embodiments. Referring also to FIGS. 2-4 , a first up-converted communication signal is generated ( 502 ). The first up-converted communication signal may be generated by first processing path P 1 , and may be based, at least in part, on a first local oscillator signal and a baseband signal. In some embodiments, the first local oscillator signal and the baseband signal may be quadrature signals.
An operating mode of the configurable amplifier 420 is selected ( 504 ). For example, when it is desired to cancel second-order harmonics of the output signal, then the first mode may be selected. Conversely, when it is not desired (or necessary) to cancel the second-order harmonics of the output signal (e.g., but rather to increase the magnitude of the output signal relative to the first mode), then the second mode may be selected.
Next, a second up-converted communication signal is generated ( 506 ). More specifically, for at least some example embodiments, when the configurable amplifier 420 is selected to operate in the first mode, the second up-converted communication signal is generated to be a substantially ninety degree phase-shifted version of the first up-converted communication signal ( 506 A). Conversely, when the configurable amplifier 420 is selected to operate in the second mode, the second up-converted communication signal is generated to be substantially the same as the first up-converted communication signal ( 506 B). Then, an output signal is generated based, at least in part, on the first up-converted communication signal and the second up-converted communication signal ( 508 ).
The first up-converted communication signal 274 may be based, at least in part, on a first local oscillator signal and a baseband signal, and the second up-converted communication signal 276 may be based, at least in part, on a second local oscillator signal and the baseband signal. In some embodiments, the second local oscillator signal may be a substantially ninety degree phase-shifted version of the first local oscillator signal when the configurable amplifier 420 is selected to operate in the first mode, and the second local oscillator signal may be substantially similar to the first local oscillator signal when the configurable amplifier 420 is selected to operate in the second mode. In some embodiments, the second local oscillator signal and the baseband signal may be quadrature signals.
In the foregoing specification, the present embodiments have been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader scope of the disclosure as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.
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A method and apparatus are disclosed for a configurable amplifier. When operating in a first operating mode, the configurable amplifier may amplify a communication signal and may cancel or attenuate a second harmonic component associated with the communication signal. When operating in a second operating mode, the configurable amplifier may amplify the communication signal without cancelling or attenuating the second harmonic component associated with the communication signal.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a multi-function optical system for forward lighting that utilizes a shared exit optic. The system is high efficiency and maintains a consistent lit appearance between functions and smooth on-road transition between functions.
[0003] 2. Description of the Related Art
[0004] Lighting systems of the past included bending light/cornering light or turn signal functions as a separate optical systems from low beam, high beam and/or fog. These separate functions were separated into different optical systems.
[0005] One prior art lighting or signaling devices is known from the patent application WO 2006/096467, which is related to U.S. Provisional Application 60/658,459, and which is incorporated herein by reference. This document discloses a lighting device that comprises a ray guide in the form of solid pieces that are tricky and expensive to produce. Performance in terms of range is reduced because of only moderately satisfactory collimation. In addition, the dimensions of the whole are relatively large.
[0006] In general, many light guide technologies for signal functions have poor efficiency and often require a large number of LEDs and/or light guides or fixtures to produce a desired lit area. In addition, these prior art technologies are either single function or have multi-functions, but the lit aspect for different colors is different.
[0007] Current high-efficiency light guides are intended for forward lighting applications and typically have a single source and a single lit aspect.
[0008] What is needed, therefore, is multi-function optical system for forward lighting that utilizes a shared exit optic having improved efficiency and that is capable of a consistent lit appearance between functions and smooth on-road transition between functions.
SUMMARY OF THE INVENTION
[0009] In one embodiment, the system uses multiple high efficiency light guides coupling into a single lens to create on-axis forward lighting (such as low beam, high beam, fog light) and off-axis forward lighting (such as bending light or cornering light) out of a single exit optic. The guides and the exit optic may be made as one piece or as multiple pieces and separated by an air gap.
[0010] An on-axis forward lighting (such as low beam, high beam, fog light) and off-axis forward lighting (such as bending light or cornering light) out of a single exit optic, while maintaining consistent lit appearance and blending beam patterns of different functions to create smooth on-road light (no streaks). One object is to incorporate additional functionality into a low beam system without increasing number of modules (or exit optic elements) in the system. One potential solution was to create a system at a modular level that could perform multiple functions while retaining identical number of exit optics.
[0011] In one aspect, one embodiment comprises a lighting device for a vehicle, comprising a first light guide that projects emits first light rays from a first light source in a first direction, at least one second light guide that projects second light rays from a second light source in a second direction, an elongated projection lens which receives said first light rays and emits them to perform a first light function, and receives said second light rays and emits them to perform a second light function.
[0012] In another aspect, one embodiment comprises an optical device for a vehicle, comprising a first light guide which receives light from a first light source and forms the light into a first beam that performs a first lighting function forward of the vehicle, at least one second light guide which receives light from a second light source and forms the light into a second beam that performs a second lighting function, a lens which i) receives the first beam and transmits the first beam in a first direction forward of the vehicle, and ii) receives the second beam and transmits the second beam in a second direction at an angle that is not parallel to a longitudinal axis of the vehicle.
[0013] In still another aspect, one embodiment comprises a lighting system for a vehicle, comprising a) a first solid, transparent body, which comprises i) a first lens, ii) a first light guide, which transmits a first beam of light to the first lens, which the first lens projects forward of the vehicle, and iii) a second light guide, which transmits a second beam of light to the first lens, which the first lens projects to the left front side of the vehicle, b) a second solid, transparent body, which comprises i) a second lens, ii) a third light guide, which transmits a third beam of light to the second lens, which the second lens projects forward of the vehicle, and iii) a fourth light guide, which transmits a fourth beam of light to the second lens, which the second lens projects to the right front side of the vehicle.
[0014] This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the following list of features:
The lighting device in which the projection lens, the first light guide, and the at least one second light guide are an integral, monolithic construction of transparent material. The lighting device in which the first light guide and the at least one second light guide are angularly spaced with a predetermined angle between each adjacent pair of the first light guide and the at least one second light guide. The lighting device in which all adjacent ones of the first light guide and the at least one second light guide are angularly spaced along an arc an equal distance apart. The lighting device in which all adjacent ones of the first light guide and the at least one second light guide are angularly spaced along an arc different distances apart. The lighting device in which the first light guide and the at least one second light guide are parabolic and generally planar light guides. The lighting device in which the first light function is a forward lighting function defining at least one of a low beam headlight or a part of a low beam headlight, a high beam headlight or a fog light for the vehicle. The lighting device in which the second light function is a side lighting function defining at least one of a turn signal light or a side light low beam headlight, a high beam headlight or a fog light for the vehicle. The lighting device in which the second light function is a side lighting function defining at least one of a turn signal light, bending light or a side light for the vehicle. The lighting device in which the first light guide contains a central plane which bisects the projection lens. The lighting device in which the first light guide and the at least one second light guide each comprise an exit face that is spaced from an entry face of the elongated projection lens. The lighting device in which the first light source comprises at least one first LED and the second light source comprises at least one second LED, wherein when the at least one first LED is activated, the first lighting function is performed and when the at least one second LED is activated the second lighting function is performed. The lighting device in which the at least one first LED and the at least one second LED are activated substantially simultaneously to perform the first and second lighting functions substantially simultaneously. The optical device in which the at least one of the first light guide or the at least one second light guide comprises a reflective edge which is of generally parabolic shape and positioned so that its focus generally coincides with the first light source, wherein the reflective edge receives light from the first light source, forms it into the first beam, and projects the first beam to the projection lens. The optical device in which the first light guide comprises a first exit edge spaced from the lens and a first generally parabolic reflective edge having a first focus that generally coincides with the first light source and the second light guide comprises a second exit edge spaced from the lens and a second generally parabolic reflective edge having a second focus that generally coincides with the second light source, wherein the first and second reflective edges of the first and second light guides receive light from the first light source and second light sources, respectively, and emit the first beam through the first exit edge to the lens and emits the second beam through the second exit edge to the lens. The optical device in which the first beam crosses the second beam inside the lens. The optical device in which the lens, the first light guide, and the at least one second light guide are an integral, monolithic construction of transparent material. The optical device in which the first and second light guides are cantilevered from the lens and further comprise a connector which connects the cantilevered light guides together, to thereby stiffen them. The optical device in which the first beam is wider than the second beam and is effective to form a headlight for a vehicle. The optical device in which the first light guide and the at least one second light guide are angularly spaced with a predetermined angle between each adjacent pair of the first light guide and the at least one second light guide. The optical device in which all adjacent ones of the first light guide and the at least one second light guide are angularly spaced along an arc an equal distance apart. The optical device in which at least one adjacent ones of the first light guide and the at least one second light guide are angularly spaced along an arc different distances apart. The optical device in which the first light function is a forward lighting function defining at least one of a low beam headlight, a high beam headlight or a fog light for the vehicle. The optical device in which the second light function is a side lighting function defining at least one of a turn signal light or a side light low beam headlight, a high beam headlight or a fog light for the vehicle. The optical device in which the first light source comprises at least one first LED and the second light source comprises at least one second LED, wherein when the at least one first LED is activated, the first lighting function is performed and when the at least one second LED is activated the second lighting function is performed, the at least one first LED and the at least one second LED being activated substantially simultaneously. The optical device in which the at least one first LED and the at least one second LED are activated substantially simultaneously to perform the first and second lighting functions substantially simultaneously. The optical device as recited in claim 14 wherein the at least one second light guide comprises a second light guide situated adjacent the first light guide and a third light guide situated adjacent the first light guide, the second and third light guides being adapted to perfume the second lighting function, while the first light guide performs the first lighting function, the first lighting function being a forward headlight function. The lighting system in which the first and second bodies are mirror images of each other. The lighting system and further comprising a light source for each respective light guide. The lighting system in which each light guide comprises a curved edge (1) to which the respective light source transmits light, and (2) which reflects the light as a beam of parallel rays. The lighting system further comprising a plurality of light sources for at least one of said light guides. The lighting system further comprising a plurality of light sources for each light guide.
[0046] These and other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0047] FIGS. 1A-1E are views of one form of the invention;
[0048] FIGS. 2A-2E are cross-sectional views of one form of the invention, viewed from above, and show various light paths;
[0049] FIGS. 3A and 3B show how the invention can be incorporated into the surface of a vehicle;
[0050] FIGS. 4 and 5 are high-level schematics which explain processing of light which the invention accomplishes;
[0051] FIGS. 6A-6F are simulations which illustrate various patterns of light projected by one form of the invention;
[0052] FIG. 6G-6I illustrates other forms of the invention;
[0053] FIGS. 7, 8, and 9 explain the term critical angle;
[0054] FIGS. 10, 11, 12, 13, 14, 15, and 16 explain the term zone of acceptance;
[0055] FIGS. 17, 18, and 19 illustrate why the LED 16 , 18 and 20 of FIGS. 1A-1D should be located generally centrally within light guide 14 ;
[0056] FIGS. 20 and 21 illustrate two types of entry of light into the light guide 14 from the LED 16 , 18 and 20 ;
[0057] FIG. 22 defines separation distances between adjacent LEDs 16 , 18 and 20 and between adjacent light guides 14 a - 14 c;
[0058] FIG. 23 shows an optical coupling medium M;
[0059] FIG. 24 illustrates an approach to reducing vibration in the invention;
[0060] FIGS. 25-30 illustrate an alternate approach to constructing one form of the invention;
[0061] FIG. 31 illustrates another form of the invention; and
[0062] FIG. 32 illustrates a top-down view of a vehicle 40 and illustrates one form of the invention mounted thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0063] FIGS. 1A-1E and FIGS. 2A-2E illustrate several forms of the invention for use in an optical device, such as a headlamp or turn signal device, for a vehicle. An assembly 10 contains a generally cylindrical lens 12 and a plurality of light guides 14 a , 14 b and 14 c. In the illustration being described, the assembly 10 is constructed of a transparent material. The assembly 10 can be molded as a single unit in a single molding step as shown in FIGS. 1A-1C or the plurality of light guides 14 a, 14 b and 14 c may be separated from the lens 12 by a predetermined distance PD, as illustrated in FIGS. 1D and 2A-2E . In one embodiment, the predetermined distance PD is on the order of about 0.5 mm.
[0064] FIGS. 2A-2E show a simplified overview of an operation of one form of the invention. In the illustration shown in FIGS. 2A-2E , an optional air space S between ends or exit faces 14 a 1 , 14 a 2 and 14 a 3 and lens entry face 12 a of the lens 12 is shown. Each light guide 14 a - 14 c, when activated, projects light rays LR 1 , LR 2 and LR 3 , respectively, from at least one light-emitting diode (LED) 16 , 18 , 20 (as best shown in FIG. 1C ) through the common projection lens 12 . However, the overall pattern of illumination depends on the combination of LEDs 16 - 20 and their respective light guides 14 a - 14 c which are activated by a controller and conventional power source (which is only shown schematically in FIG. 2A for ease of description). The controller may be provided on the printed circuit board (PCB) with the LEDs 16 - 20 , or provided in the headlamp assembly 10 or elsewhere on the vehicle. For example, in FIG. 2B , only the light guide 14 a and LED 16 are activated to generate a forward or first lighting function, such as the central pattern P 1 , as illustrated in FIG. 2B and shown in FIG. 6A . In one embodiment, this pattern P 1 can be used as a high-beam or a low-beam headlight in a vehicle. The light guides 14 a or 14 c and their associated LEDs 18 and 20 , respectively, are adapted to provide or generate a second lighting function such as a turn signal, DBL or side lighting function. It should be understood that multiple LEDs or an array of LEDs may be provided to one or more of the light guides 14 a - 14 c if desired. Also, the LEDs could perform the same or different lighting functions. FIG. 1E illustrates the use of multiple LEDs 16 a, 16 b, 18 a, 18 b, 20 a and 20 b that could be used with the light guides 14 a - 14 c.
[0065] In FIG. 2C , light guide 14 b and LED 18 alone are activated to pass light rays LR 2 and produce pattern P 2 (illustrated on the left side of FIG. 6C ). This pattern P 2 can be used, for example, to illuminate the left front side of the vehicle or provide a turn signal when making a left turn. In FIG. 2D , light guide 14 c and LED 20 alone are activated and produce pattern P 3 on the right side. This pattern P 3 can be used to illuminate the right front side of the vehicle or provide a turn signal when making a right turn.
[0066] Thus, the patterns P 2 and P 3 can be used as turn signal indicators. As another alternate, the patterns P 2 and P 3 can be used as fog lights or used in a dynamic bending lamp or side lighting function.
[0067] The following Table I summarizes some of the functions:
[0000]
TABLE I
Function
Middle
Right
Left
A
B
C
CASE
14A
14B
14C
LEDs Activated
1
Low
Low
Low
All LEDs on
Beam
Beam
Beam
together for
(Flat)
(Flat)
(Flat)
Low Beam.
Each contributes
to different
part of Low Beam
2
Bending
Bending
Bending
LEDs sequenced
(Side)
(Side)
(Side)
(based on turning
angle or other
inputs)
3
Low
Auxiliary
Auxiliary
High Beam to
Beam
High
High
supplement
(Flat)
Beam
Beam
another High
Beam.
4
High
Low
Low
Beam
Beam
Beam
(Flat)
(Flat)
5
Fog
Auxiliary
Auxiliary
High Beam
High
High
to supplement
Beam
Beam
another
High Beam.
6
Fog
Bending
Bending
(Side)
(Side)
7
DRL
Low Beam
Low Beam
(Flat)
(Flat)
8
DRL
Bending
Bending
(Side)
(Side)
9
DRL/Turn
Low
Low
2 LEDs (white,
Beam
Beam
amber) in
(Flat)
(Flat)
14a middle
guide
10
DRL/Turn
Auxiliary
Auxiliary
2 LEDs (white,
High
High
amber) in
Beam
Beam
14a middle
guide
11
Stop/Turn
Backup
Backup
2 LEDs (red,
amber) in
14a guide
Functions can be interchanged between guide locations (14a, 14b, 14c)
Each Blade can make following patterns: High Beam; Low Beam Flat; Fog and Signal (Stop, Turn, Tail)
[0068] Separate illumination of each light guide 14 a - 14 c has been described. It should be understood that multiple light guides 14 a - 14 c can be selectively activated individually or one or more can be activated simultaneously. For example, as in FIG. 2E , LED 16 and light guide 14 a can produce pattern P 1 (a headlight beam) while LED 18 and light guide 14 b can simultaneously produce pattern P 2 for illuminating the left front side of the vehicle during a left turn or to provide a dynamic bending light during a turn. One benefit or advantage of this arrangement is that the overall pattern in FIG. 2E is aesthetically pleasing because the light intensity is rather uniformly distributed across the combined patterns P 1 and P 2 without significant gaps or streaks on the roadway which is illuminated.
[0069] Also, an external surface 12 b of the lens 12 of FIGS. 1A-1C and 2A-2E can be adapted to be made conformal with an external surface V 1 ( FIGS. 3A and 3B ) of the vehicle V, as shown in the left side of FIG. 3B , for styling purposes and to meet aerodynamic requirements. No secondary protective lens is required. In addition, the lens 12 is highly adaptable because it can be curved in multiple dimensions, as indicated by the wire frame sketch in FIGS. 3A-3B .
[0070] This discussion will return to the structure of the assembly 10 of FIGS. 1A-1D and FIGS. 2A-2E . Each light guide 14 a - 14 c contains a reflective surface 22 which may bear a reflective coating, such as an aluminum film. The reflective surface 22 is of the parabolic type. The lens 12 , while a single, integral and monolithic unit in one form of the invention, can be conceptually divided into multiple functional sections, two of which lens sections 12 c and 12 d, are schematically shown in FIG. 4 . The light guide 14 a transmits most of the light from LED 16 (not shown in the figure for ease of illustration) to the lens section 12 c, which focuses or spreads the rays LR 1 according to the shape of lens section 12 c. In FIG. 5 , the light guide 14 c, for example, transmits its rays LR 3 to both the lens sections 12 c and 12 d. The particular allocation of the light between lens sections 12 c and 12 d for this light guide 14 c will depend on the design of the system. Alternately, in one form of the invention, a majority of the light from light guide 14 c travels through the lens section 12 d.
[0071] As mentioned earlier, FIGS. 6A through 6F illustrate simulations illustrating operation of the apparatus of FIGS. 1A-1C and 2A-2E . In FIG. 6A , only the light guide 14 a and LED 16 are illuminated to provide the pattern P 1 , and in FIG. 6B , only the light guide 14 c and LED 20 are illuminated to provide the pattern P 4 to provide a bending light to the right.
[0072] In FIG. 6C , light guides 14 a and 14 c and LEDs 16 and 20 , respectively, are illuminated to provide the pattern P 3 to bend light to the left. In FIG. 6D , the light guide 14 b and LED 18 are illuminated to provide the pattern P 2 .
[0073] In FIG. 6E , the light guides 14 a and 14 b of FIGS. 6A and 6B are illuminated together by LEDs 16 and 18 , respectively, to provide a pattern P 2 that provides a bending light to the left. It is pointed out that the light rays LR 2 of light guide 14 b cross the light rays LR 1 of light guide 14 a within the lens 12 . The result is that the projected beams or light rays LR 1 and LR 2 overlap as illustrated in FIG. 2E and indicated in FIG. 6E to provide the pattern P 2 .
[0074] In FIG. 6F , all three light guides 14 a, 14 b, and 14 c and their associated LEDs 16 , 18 and 20 , respectively, are illuminated and indicates the uniformity of illumination and a pattern P 5 which is obtained. A plurality of scallops 12 c in the exit face 12 b of the lens 12 in FIG. 1A promote this uniformity by introducing an amount of scattering into the projected beams or rays LR 1 , LR 2 and LR 3 .
[0075] In one form of the invention, light sources or LEDs 16 , 18 and 20 are mounted on a single printed-circuit board 34 ( FIGS. 22 and 23 ). These LEDs 16 , 18 and 20 are properly aligned with entry surfaces 14 a 1 ( FIG. 22 ), 14 a 2 and 14 a 3 of light guides 14 a, 14 b and 14 c, respectively, so that during assembly, all light sources or LEDs 16 , 18 and 20 can be installed by a single process of installing a single circuit board. This alignment process will be explained in more detail later herein.
[0076] FIGS. 6G, 6H and 61 illustrate various embodiments of the invention in which multiple light guides 14 a - 14 e are present. It should be understood that more or fewer light guides 14 a - 14 e could be provided, such as the embodiment of FIG. 6G-6I . Also, multiple LEDs could be used with each light guide 14 a - 14 e. Also, a device could be provided with the light guide 14 a in combination with only one of either light guide 14 b or 14 c or other light guides, as illustrated in FIG. 32 and described later herein.
[0077] In the embodiment being described, note that the plurality of light guides, such as light guides 14 a - 14 - c in FIGS. 1A and 2A and light guides 14 a - 14 e in FIGS. 6G-6I are arranged in a generally equally spaced angular arrangement along an arc a predetermined angle PA apart. In the illustration, the predetermined angle is about 30 degrees. It should be understood, however, that they could be unequally spaced apart, such that, for example, the angle PA 1 between light guide 14 a and light guide 14 c is larger than the angle PA 2 between light guide 14 a and light guide 14 b, as illustrated in FIG. 6H . The particular spacing may, therefore be varied and at least partly driven by the function to be performed and the environment where the light guides 14 a - 14 e will be situated.
ADDITIONAL CONSIDERATIONS
[0078] 1. FIG. 7 is a view of the light guide 14 a viewed in the direction of arrow A in FIG. 1A . FIG. 7 illustrates the LED 16 . In one form of the invention, the LED 16 should be located generally central or midway between wall 14 a 2 and 14 a 3 to the light guide 14 a as opposed to being displaced to the left or right in FIG. 7 , as will now be explained.
[0079] FIG. 7 illustrates Snell's Law of refraction. The angle A 2 of the transmitted ray follows the sine-function given in the Figure. However, as indicated in FIG. 8 , when the incident angle A 1 reaches a Critical Angle, the transmitted ray does not exit the light guide 14 a, but instead travels parallel to the surface of the light guide 14 a as indicated. Total internal reflection occurs when the incident angle Al exceeds the Critical Angle as illustrated in FIG. 9 .
[0080] These facts allow one to deduce a Zone of Acceptance ( FIGS. 10-12 ). In FIGS. 10 and 11 , in order for total internal reflectance to occur, the incoming rays must exceed the Critical Angle. These two Critical Angles are combined into FIG. 12 which shows the Zone of Acceptance. The angles of the incoming light rays, respectively, should lie within this zone for total internal reflectance to occur.
[0081] It is pointed out that a light ray having less than the Critical Angle will also be reflected internally. However, such a ray will experience both transmission and reflection at each encounter with the surface, as best shown in FIG. 10 . In this case, if one assumes a reflection coefficient of 0.8, for example, then after ten reflections, the remaining intensity in the ray will be the initial intensity multiplied by 0.8 raised-to-the-tenth-power, which is considered negligible. Such a ray is effectively lost. In contrast, an incident ray at an angle greater than the Critical Angle behaves differently and does not experience this reduction in intensity.
[0082] At this point, a small complication arises, namely, that the Zone of Acceptance has been computed based on rays located within the light guide 14 a, but the incoming rays outside the light guide 14 a will be refracted as they enter the light guide 14 a. FIG. 13 shows the Zone of Acceptance lowered into the light guide 14 a for ease of explanation. FIG. 14 shows a ray within the light guide 14 a at the Critical Angle. FIG. 15 shows how an incoming ray is refracted according to Snell's Law to produce the ray of FIG. 14 . The equations point out that the refraction at the surface causes the Zone of Acceptance to open up somewhat outside the light guide 14 a because the index of refraction of air is less than that of the light guide 14 a. Therefore, the actual Zone of Acceptance is adjusted for the incoming refraction of FIG. 15 and is represented generally by FIG. 16 .
[0083] Now, the positioning of the LED 16 can be considered. This analysis applies to all the light guides 14 a, 14 b and 14 c, but is only described relative to light guide 14 a for ease of illustration. FIG. 17 shows the LED 16 positioned on the central axis AX relative to the entry surface 14 a 1 of light guide 14 a. FIG. 18 shows that LED 16 , but with the Zone of Acceptance boundary ZA superimposed. In FIG. 18 , as the boundary ZA indicates, the solid rays SR from LED 16 will lie within the Zone of Acceptance and some phantom rays PR (represented by dashed lines in the figure) will not. The phantom rays PR will be lost because they experience the repeated losses of reflection/transmission described above or they simply are directed away from the entry surface 14 a 1 of the light guide 14 a.
[0084] However, if the LED 16 is shifted away from the central axis AX, as illustrated in FIG. 19 , then all phantom rays PR are still lost because they lack the proper angles. Nothing has changed in this respect. In addition, solid ray R 1 is also lost because it fails to enter the light guide 14 a entirely.
[0085] Therefore, for maximum optical coupling, the LED 16 should lie on the central axis AX of the light guide 14 a to avoid loss of rays such as R 1 .
[0086] 2. It is possible that future vehicles may be required to significantly reduce power expenditure in their lighting systems and some ways to achieve that reduction will now be considered.
[0087] A gasoline or diesel powered engine of a modern passenger automobile has a power rating in the dozens of kilowatts or a few hundred kilowatts, one kilowatt being about 1.25 horsepower. However, the power consumed by the lighting system of such a vehicle lies in the dozens or hundreds of watts. Thus, the power produced by the engine is roughly one thousand times larger than the power consumed by the lighting system.
[0088] However, electric vehicles are becoming more abundant. Their electric motors generally also have power ratings in the dozens of kilowatts, similar to current gasoline engines. However, under current technology, the electric batteries used to power the electric motors do not possess comparable energy density to that of liquid fuels. Electric power is at a premium in such vehicle.
[0089] Therefore, as the usage of electric vehicles becomes more widespread, it may become important to economize on electric power consumption. In this context, consideration will be given to maximizing the optical coupling between the LED 16 and the light guide 14 a to reduce losses and to thereby allow usage of less powerful LEDs 16 . The positioning of FIG. 18 represents one improvement in optical coupling.
[0090] FIG. 20 is a rough graphical rendition of the Fresnel Equations, which indicate the theoretical reflection coefficients for specular reflection for various angles of incidence. FIG. 20 indicates that the reflection coefficient is minimal and thus the transmission coefficient is maximal at an angle of incidence of zero as measured with respect to the surface normal.
[0091] Therefore, to minimize reflection at the interface IF where the light enters the light guide 14 a, the light rays should enter perpendicular (as illustrated in FIG. 20 ) to the surface 14 a 1 . If the LED 16 produces parallel rays, then this is easily accomplished using a flat entry face 14 a 1 . However, if the LED 16 acts as a point source and produces radially directed rays, then the entry face F may be curved so that the rays enter generally perpendicular to the entry face F. In one embodiment, the entry face 14 a 1 in one or more of the light guides 14 a - 14 c is hemispherical. This is illustrated in FIG. 21 .
[0092] 3. Reflective losses occur where the light from an LED 16 , 18 or 20 exits the LED 16 , 18 or 20 and enters the air, for example, at area A 1 in FIG. 23 and then where light exits the air and enters the light guide surface at area A 2 . These losses can be reduced by an impedance-matching material M shown in FIG. 23 . The required index of refraction of the matching material M is calculated in a known manner.
[0093] 4. In one form of the invention, the LEDs 16 , 18 and 20 are contained on a single, common printed circuit board (PCB) 34 as illustrated in FIGS. 23 and 24 . The spacing between adjacent pairs of the LEDs 16 , 18 and 20 is equal to a distance between the central axes of the corresponding light guides 14 a - 14 c. In FIG. 23 , the LEDs 16 , 18 and 20 are located as shown and mounted on the PCB 34 . The distance D 1 equals the distance D 2 and the distance D 3 equals the distance D 4 . A similar principle applies to the multiple light guides 14 a - 14 c in other Figures. Thus, the LED to LED distance of an adjacent pair of LEDs 16 , 18 and 20 is the same as the light guide to light guide distance of the corresponding light guides 14 a - 14 c.
[0094] 5. FIG. 24 is a cross section of one conception of another embodiment of the invention. Light guides 14 a - 14 c, being cantilevered from the lens 12 , can experience vibration as indicated by the dashed lines. This vibration can be reduced by fastening adjacent light guides 14 a - 14 c together by using bars 44 near the ends of the light guides 14 a - 14 c. This connection serves to stiffen the vibrating elements. It also increases the mass of the vibrating elements and thus changes the resonant frequency. Alternately, the light guides 14 a - 14 c can be fastened to the vehicle structure by brackets or cassettes, one of which is shown schematically by block 46 .
[0095] 6. FIG. 25 indicates the structure of FIG. 25 being cut or molded into three pieces by the dashed lines. FIG. 26 indicates that the three pieces are rendered identical in shape. FIG. 27 conceptually rotates or pivots the three pieces of FIG. 26 about points P in FIG. 27 .
[0096] FIG. 28 indicates a shape which can be deduced from FIG. 27 . FIG. 29 indicates lens 12 being cut off from the shape of FIG. 28 . FIG. 31 indicates three identical shapes of FIG. 29 assembled into a structure with a lens 12 ′ or a portion of lens 12 ′ added.
[0097] The apparatus of FIG. 30 provides the benefit of utilizing three copies of a single molded component, namely that of FIG. 29 , to form one embodiment of the invention. The single molded component is simpler to fabricate compared with the structure of FIGS. 1A-1C .
[0098] In another embodiment, the assembly 10 in FIG. 31 can be split, molded or cut along dashed line DL to produce two mirror-image halves on the right side of the Figure. Fabricating a mold for such a half is simpler than fabricating a mold for the entire assembly 10 and the molding process for such a half is simpler as well.
[0099] 7. Some characteristics of various embodiments of the invention will be discussed. FIG. 10 is a schematic exploded view of one form of the invention. The light guide 14 a can be said to have an exit face 14 a 4 which transmits light into the entry surface 12 a of projection lens 12 . The exit face 14 a 4 is thin and broad because the thickness TH is less than the height H. It should be understood that various ratios of height H to thickness TH are possible and ratios of height H to thickness TH may be 5 and 50 or any of the values therebetween (e.g., 5 to 50).
[0100] The light guide 14 a generates a sheet or beam of light rays LR 1 in the example, indicated by arrow 36 . The projection lens 12 receives the sheet or beam and expands it transversely, producing a beam indicated by the dashed arrows 38 . The various patterns were described earlier herein relative to FIGS. 6A-6F .
[0101] 8. FIG. 32 illustrates one form of and embodiment of the invention. A vehicle 40 contains two assemblies 10 which are mirror-images of each other. Light guide 14 a and LED 16 in both assemblies 10 together generate the low headlight beam for the vehicle 40 . Light guide 14 c of the right-hand assembly 10 in FIG. 32 generates a right turn signal or a right turn headlight, fog light, daytime running light (DRL) or bending light, which illuminates the right front of the vehicle during a right turn. Light guide 14 b generates a left turn signal, fog light, DRL or bending light or a left turn headlight beam.
[0102] 9. In one form of the invention, the lens 12 is symmetrical about an internal axis or plane. This plane or axis can coincide with the central plane of light guide 14 a. The lens surface 12 b is conical or curved and may have the scallops 12 c as mentioned earlier herein.
[0103] 10. The light guides 14 a - 14 c are illustrated as being flat. However, it should be understood that they can be curved and still function properly.
[0104] 11. It should also be appreciated that the light guides 14 a - 14 c do not have to be the same size, one or more of them can be different sizes.
[0105] 12. It should also be understood that different colored LEDs 14 a - 14 c could be used. Also, each light guide may have a plurality of different color LED, such as white, amber, yellow, or other color to facilitate performing different lighting functions, such as the forward lighting function or turn lighting functions mentioned earlier.
[0106] 13. Advantageously, the present invention has the following advantages:
reducing packaging size by placing multiple functions in one optical system and using the same exit optic for all functions; consistent lit appearance between different functions; smooth transition between functions on the road (no visible streaks where low beam meets bending light); all entrance guide may have LEDs that are placed on a single PCB to simplify electronics; use of separate optical systems for separate functions; and does not include functions, such as bending or cornering, that are not required to be included.
[0113] 14. The light guides can be designed to form a plurality of light patterns, such as cut-off, signal, and the like.
[0114] This invention, including all embodiments shown and described herein, could be used alone or together and/or in combination with one or more of the features covered by one or more of the claims set forth herein, including but not limited to one or more of the features or steps mentioned in the bullet list in the Summary of the Invention and the claims.
[0115] While the system, apparatus, process and method herein described constitute preferred embodiments of this invention, it is to be understood that the invention is not limited to this precise system, apparatus, process and method, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.
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A light for a vehicle. Two or more light guides each project a sheet of light to a common projection lens, but in different directions. Each light guide is selectively actuable by the driver. The projection lens receives the sheets of light, expands them in the horizontal direction, and projects them in the same general direction as received. Thus, the driver can selectively illuminate various regions of the terrain.
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BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to electroluminescent displays, and more particularly to an electroluminescent display having reversible polarity for creating images on an electroluminescent panel.
2. Description of the Prior Art
Electroluminescent displays represent a class of flat panel displays that are used in a wide variety of applications. For example, the displays are currently used in military systems, elevators and hospital monitoring equipment.
Electroluminescent displays generally include an electroluminescent layer such as a ZnS phosphor doped with an activator such as Mn. The electroluminescent layer is placed between two dielectric layers. A first series of parallel and longitudinal electrodes adjoin the first dielectric layer and a second series of parallel and longitudinal electrodes adjoin the second dielectric layer in an orthogonal orientation with respect to the first series of electrodes.
The first series of electrodes may be referred to as row electrodes and the row electrodes may be constructed of aluminum. The second series of electrodes may be referred to as column electrodes. The column electrodes are typically transparent and made of indium-tin oxide.
An intersection of the first series and second series of electrodes defines a picture element referred to as a pixel. The resolution of the electroluminescent display is determined from the number of pixels.
The electroluminescent displays operate by applying a voltage across the electroluminescent layer via the first series and second series of electrodes. Each pixel within the electroluminescent layer will emit light when a sufficient voltage is present between the electrodes which correspond to the pixel. The luminescence of the particular pixel will be determined from the magnitude of the voltage across the pixel.
Electroluminescent displays may suffer from a problem referred to as a `latent image` or `retained image` phenomenon. This phenomenon results in smearing and ghost images wherein an image which has been displayed for a long period of time may be burned into the display (i.e. the image is apparent to varying degrees even though it is not electrically written on the display). Accordingly, this problem is most severe in areas of the electroluminescent layer which are subject to the greatest use. These images may appear only after a few hours or several days or months depending upon the technology and electronic voltage drive scheme utilized.
It is believed that the basic cause of this phenomenon is the occurrence of sulfur vacancies within the Mn-doped ZnS phosphor. These sulfur vacancies diffuse in a non-uniform manner within the phosphor with the passage of time and thereby change the electrostatics of the device.
This theory is supported by the fact that the occurrence of a latent image is greatly dependent upon the electronic voltage drive scheme. It appears that the latent image phenomenon is a result of the pixels having a voltage-time average that is non-zero when averaged over several scans through the model. The non-zero voltage-time average causes an asymmetrical charge distribution to be built up over time and possibly a spatially preferential accumulation of sulfur vacancies within the phosphor.
One approach to reduce the severity of the latent image phenomenon is to utilize a symmetric voltage drive scheme. Symmetric voltage drive schemes are well known in the art and operate by first generating a plurality of positive voltage pulses followed by a plurality of negative voltage pulses which are equal in magnitude to the corresponding positive voltage pulses. The average electric field within the ZnS phosphor approaches zero when a symmetric waveform is used to drive the electroluminescent display and there is no spatially preferential accumulation of sulfur vacancies within the phosphor.
However, the use of a symmetric voltage drive scheme is undesirable inasmuch as pixel brightness is reduced up to 50% as compared to the use of an asymmetrical voltage drive scheme. This reduction in brightness of the electroluminescent display is unacceptable when high ambient viewability is required. It has also been noticed that a symmetric voltage drive scheme may cause a ghosting phenomenon in certain display modes such as scrolling characters across a display. In addition, the response time of an electroluminescent display which is driven by a symmetric voltage drive scheme is slower than an electroluminescent display driven by an asymmetrically driven electroluminescent display.
Asymmetrical voltage drive schemes are also well known in the art. These voltage drive schemes operate by generating a first refresh voltage pulse which is followed by a plurality of write voltage pulses corresponding to a first write cycle. The first write cycle may be followed by a second refresh pulse and a second write cycle and the pattern is repeated. The refresh pulses have a polarity which is opposite that of the write pulses. The use of asymmetrical voltage drive schemes offers the advantages of faster response time and a brighter electroluminescent display without the ghosting phenomenon in certain display modes.
Despite the advantages of an asymmetrical drive scheme, the magnitude of the opposite polarity drives are not equal and a charge may accumulate at an interface of the electroluminescent layer and a dielectric layer resulting in the appearance of ghost images within the electroluminescent display.
SUMMARY OF THE INVENTION
The invention provides for an electroluminescent display and a method of driving the same. In particular, the electroluminescent display is preferably driven with an asymmetric voltage drive scheme which eliminates the development of a preferential charge distribution at specific pixel sites.
The electroluminescent display in accordance with the present invention includes an electroluminescent layer for generating images and a plurality of first electrodes adjacent a first side of the electroluminescent layer and a plurality of second electrodes adjacent a second side of the electroluminescent layer and orientated to intersect the first electrodes.
The electroluminescent display in accordance with the present invention may further include a waveform generator for preferably applying refresh voltage signals and write voltage signals to the electroluminescent layer via the first and second electrodes.
The electroluminescent display in accordance with the present invention preferably reverses the polarity of the refresh voltage signals and the write voltage signals after a predetermined transition time to reduce latent images within the electroluminescent display.
The preferred usage of an asymmetrical drive scheme in accordance with the present invention provides a brighter electroluminescent display which has a faster response time.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a portion of a prior art electroluminescent display panel.
FIG. 2 is a block diagram of a present preferred embodiment of an electroluminescent display panel and the corresponding voltage drive scheme components.
FIG. 3 is a plot of a waveform of a typical prior art symmetrical voltage drive scheme.
FIG. 4 is a plot of a waveform of a typical prior art asymmetrical voltage drive scheme.
FIG. 5 is a plot of an embodiment of a waveform of the voltage drive scheme in accordance with the present invention.
FIG. 6 is another plot of an embodiment of a waveform of the voltage drive scheme in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIG. 1, an electroluminescent panel 10 includes an electroluminescent layer 12 which is positioned between a first dielectric layer 14 and a second dielectric layer 16. The first dielectric layer 14 and the second dielectric layer 16 act as capacitors to protect the electroluminescent layer 12 from DC electrical currents. The electroluminescent panel 10 further includes a plurality of first electrodes 18 adjacent the first dielectric layer 14, and a plurality of second electrodes 20 adjacent the second dielectric layer 16 and a glass substrate 21. The second electrodes 20 are preferably transparent and constructed of indium-tin oxide (ITO).
The electroluminescent layer 12 may be a Mn-doped ZnS phosphor. Electrons flow between the first electrodes 18 and the second electrodes 20 when the difference in voltage between the first electrodes 18 and second electrodes 20 exceeds a threshold voltage (e.g. 160 volts). The electrons traveling between the first electrodes 18 and the second electrodes 20 excite the Mn within the electroluminescent layer 12 and photons are thereby emitted through the second dielectric layer 16 and the second electrodes 20 to form an image upon the glass substrate 21.
The drive circuitry for the electroluminescent panel 10 is shown in FIG. 2. The drive circuitry preferably includes a waveform generator 22 for producing voltage signals or pulses to drive the electroluminescent panel 10. The driver circuitry also includes a row driver 26 and a column driver 28 connected with the waveform generator 22.
The electroluminescent panel 10 may be preferably driven in a conventional manner utilizing a row-at-a-time scheme. In particular, the waveform generator 22 applies a voltage waveform to the row driver 26 via a first line 24. The voltage waveform preferably has a magnitude approximately equal to the threshold voltage of the electroluminescent panel 10.
The row driver 26 preferably operates in a successive order to sequentially apply the threshold voltage waveform to each row of pixels within the electroluminescent panel 10 via the first electrodes 18. The row driver 26 may include a shift register to provide the preferred sequential operation. A write cycle 38 is complete when each row of pixels within the electroluminescent panel 10 has received the threshold voltage.
The waveform generator 22 may additionally provide a voltage waveform to the column driver 28 via a second line 25. The voltage waveform applied to the column driver 28 may be a fixed constant voltage drive pulse (e.g. 60 volts DC) if the electroluminescent display is operating as a graphics panel.
Alternatively, the waveform generator 22 may include a ramp voltage generator for applying a variable amplitude drive pulse (60 volts DC ramp) to the column driver 28 if the electroluminescent display is operating as a gray-scale panel. The luminescence of each individual pixel may be varied through the utilization of a ramp voltage generator and regulating the magnitude of the voltage applied to each of the pixels. In particular, the column driver 28 may operate as a sample-and-hold device wherein the ramped voltage is sampled and retained at a predetermined time depending upon the desired luminance of the pixel.
The column driver 28 may receive address, data and clock information from a controller 32 via a bus 30. The controller 32 applies a plurality of parallel data signals to the column driver 28 to control the timing of the sampling of the ramp voltage thereby. Each instantaneously sampled voltage is subsequently applied to an individual pixel via the second electrodes 20 thereby controlling the luminescence of the pixel and permitting gray-scaling. This procedure is repeated for each row of pixels in the electroluminescent panel 10 to complete a write cycle 38. The write cycles 38 are subsequently repeated to create visual images on the electroluminescent panel 10.
A plot of a prior art symmetrical waveform for driving the pixels is shown in FIG. 3. In particular, a plurality of first negative write voltages 41a are applied to the pixels during a first write cycle 38a. Next, a plurality of first positive write voltages 42a, which may be equal in magnitude to the first negative write voltages 41a, are applied to the pixels during a second write cycle 38b. The polarity of each write cycle 38 continues to alternate throughout the operation of a symmetrical voltage drive scheme. Alternatively, the symmetrical voltage drive scheme may reverse the polarity of the voltage pulses after every other voltage pulse or every nth voltage pulse.
Utilizing a symmetric voltage drive scheme greatly reduces the latent image phenomenon because alternating the polarity of the voltage pulses reduces an electrical charge being accumulated at the interface of the first dielectric layer 14 or the second dielectric layer 16.
A plot of a typical prior art asymmetrical waveform for driving the electroluminescent panel 10 is shown in FIG. 4. In particular, a plurality of first write pulses 44a are applied to the pixels within the electroluminescent panel 10. The number of write pulses 44a within each write cycle 38a corresponds to the number of rows of pixels within the electroluminescent panel 10. The first write cycle 38a is followed by a first refresh pulse 43a simultaneously written to all pixels within the electroluminescent panel 10.
The first write pulses 44a and the first refresh pulse 43a are opposite in polarity and may form a first frame 39a. In addition, applying write pulses 44a with a polarity opposite of the refresh pulses 43a reduces ghost images by canceling an electrical charge which accumulates at the interface of one of the first dielectric layer 14 or the second dielectric layer 16.
Thereafter, a second frame 39b including a plurality of second write pulses 44b forming a second write cycle 38b and a second refresh pulse 43b is applied to the pixels within the electroluminescent panel 10. Each write pulse 44a has the same polarity and each refresh pulse 43a has the same polarity as shown in FIG. 4. An asymmetrical voltage drive scheme repeats this sequence of voltage pulses to create images within the electroluminescent display.
Accordingly, two pulses of light are emitted from a pixel during each frame 39 when the asymmetrical voltage drive scheme is utilized (i.e. refresh pulse 43 and write pulse 44) as opposed to a single pulse of light during each write cycle 38 when the symmetrical voltage drive scheme is utilized (i.e. either a negative write voltage 41 or positive write voltage 42).
Therefore, the electroluminescent display is brighter when driven by an asymmetrical voltage drive scheme and it is therefore preferred to utilize an asymmetrical voltage drive scheme to illuminate the pixels within the electroluminescent panel 10.
An embodiment of a modified asymmetric voltage drive scheme in accordance with the present invention is shown in FIG. 5. The modified asymmetric voltage drive scheme may be utilized with either graphic style electroluminescent panels 10 or gray scale electroluminescent panels 10.
The modified asymmetric voltage drive scheme in accordance with the present invention may include patterns (a first pattern 48 and a second pattern 49 are shown in FIG. 5).
The sequence of voltage pulses within the first pattern 48 of the modified asymmetric voltage drive scheme may include a first refresh pulse 50a which may be simultaneously applied to all pixels. The first pattern may next include a plurality of first negative write pulses 51a which are individually applied to a corresponding row of pixels. The negative write pulses 51 and the positive write pulses 53 may form write cycles 38 as shown in FIG. 5.
The first pattern 48 may additionally include a second refresh pulse 50b followed by a second write cycle 38b which has a plurality of second negative write pulses 51b. This sequence repeats for a period of time thereby defining the first pattern 48.
At the transition times T=Tr, 2Tr, etc., the polarity of the modified asymmetrical voltage drive scheme may be reversed as shown in FIG. 5. Following the transition time Tr on the voltage waveform plot, the sequence of pulses follow a second pattern 49 of the modified asymmetrical voltage drive scheme in accordance with the present invention.
A second pattern 49 preferably includes a first negative refresh pulse 52a which may be applied to all pixels. The first negative refresh pulse 52a may be followed by a plurality of first positive write pulses 53a which define a third write cycle 38c.
This sequence is followed for a second period of time thereby defining a second pattern 49. The polarity of the voltage pulses is reversed after the second pattern 49 at time 2Tr as shown in FIG. 5. The number of voltage pulses 50, 51 within the first pattern 48 and the number of voltage pulses 52, 53 within the second pattern 49 are preferably equal but may be varied.
The voltage pulse generated immediately prior to the transition time Tr is preferably inverted and repeated following the transition time Tr. For example, as shown in FIG. 5, a positive refresh pulse 50 may be applied to the electroluminescent panel 10 at a moment in time just prior to the transition time Tr and a negative refresh pulse 52 may immediately follow the transition time Tr.
Alternatively, a write cycle 38 of positive write voltage pulses 53 may be applied to the electroluminescent panel 10 at a moment in time just prior to the transition time Tr and a write cycle 38 of negative write voltage pulses 51 may immediately follow the transition time as shown in FIG. 6.
Any preferential interface charge distributions which have accumulated prior to the transition times Tr, 2Tr, etc. may form latent images on the electroluminescent panel 10. Such a preferential interface charge distribution may be neutralized by an opposite preferential charge built up at an opposite interface after the transition times Tr, 2Tr, etc. Accordingly, the latent images on the electroluminescent panel 10 are greatly reduced.
A variety of methods for calculating the timing of the transition times Tr, 2Tr, etc. may be utilized. Preferably, the polarity of the voltage pulses may be reversed before the latent image formation becomes objectionable. Additionally, display system usage and architecture will affect the time at which the polarity must be reversed.
Preferably, a sequence of voltage pulses may be defined wherein the first pattern 48 and second pattern 49 include an equal number of voltage pulses and the polarity may be reversed within every few minutes. Alternatively, the sequence of pulses may include a first pattern 48 and a second pattern 49 wherein the polarity of the voltage pulses may be reversed after the application of a second refresh pulse 50, 52 or a second write cycle 38 within the pattern. In addition, the polarity of the pulses may be alternated whenever the electroluminescent display is turned off and on.
The electroluminescent display preferably includes a polarity reverser 23 to invert the polarity of the voltage pulses. A polarity reverser 23 may be coupled with the waveform generator 22 and the row driver 26 and the column driver 28 as shown in FIG. 2. In addition, the polarity reverser 23 may be coupled with a timer 19 which calculates the transition times Tr, 2Tr, etc. for reversing the polarity of the voltage drive pulses. Alternatively, the waveform generator 22 may instruct the polarity reverser 23 to reverse the polarity via a third line 27.
The polarity reverser 23 may be configured to reverse the polarity of the voltage pulses when the electroluminescent display is turned off or on to simplify the electroluminescent display hardware.
The polarity reverser 23 may receive power from a power supply 29 and apply the power to the row driver 26 and the column driver 28. The polarity reverser 23 may reverse the polarity of the power applied to the row driver 26 and the column driver 28 at the transition times Tr, 2Tr, etc. Accordingly, the polarity of the write pulses 51, 53 and the refresh pulses 50, 52 applied to the pixels is reversed when the polarity of the power applied to the row driver 26 and the column driver 28 is reversed.
While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting to the scope of the invention which is to be given the full breadth of the following claims and all equivalents thereof.
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An electroluminescent display having reversible polarity and a method for reducing latent images in the electroluminescent panel is provided. The electroluminescent display includes a waveform generator for supplying voltage pulses to illuminate pixels within the electroluminescent panel. The electroluminescent display according to the invention periodically reverses the polarity of the voltage pulses to reduce latent images in the electroluminescent panel. The electroluminescent display preferably utilizes an asymmetrical drive scheme to provide a brighter electroluminescent display.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wheel suspension system for automobiles, and particularly to an improvement in a wheel suspension system which comprises a pair of upper and lower control arms connected at their leading ends to a knuckle which carries a wheel, each of the base ends of the arms being vertically swingably pivoted respectively at front and rear spaced positions to a vehicle body.
2. Description of the Prior Art
Such wheel suspension systems are well known as a double wishbone type (for example, see Japanese Patent Publication No. 28123/69).
In such conventional wheel suspension system, the upper and lower control arms are pivoted at their base ends respectively through elastic members to horizontal shafts fixedly mounted on a vehicle body. Therefore, the longitudinal compliance and caster rigidity during braking are governed by spring constants of these elastic members.
In general, in order to prevent shocks from being transmitted to the vehicle body to the utmost, such as shocks generated when a wheel gets over a protrusion on a road surface, it is necessary to provide the wheel suspension system with a large longitudinal compliance. And in order to assure a straight advancing property of a wheel during braking, it is necessary to give a large caster rigidity to the wheel suspension system.
In the conventional wheel suspension system, however, if the spring constant of an elastic member is set at a smaller value for providing a larger longitudinal compliance, the caster rigidity is reduced to degrade the straight advancing property of the wheel. On the contrary, if the spring constant of the elastic member is set at a larger value to provide a larger caster rigidity during braking, the longitudinal compliance is reduced, accompanied by an adverse deterioration of the riding comfort. Consequently, it is difficult to satisfy both of the longitudinal compliance and the caster rigidity during braking.
SUMMARY OF THE INVENTION
The present invention has been accomplished with such circumstances in view, and it is an object of the present invention to provide a wheel suspension system of the type described above, which can satisfy both the longitudinal compliance and the caster rigidity during braking.
According to the present invention, the above object is attained by providing a wheel suspension system for automobiles comprising a pair of upper and lower control arms connected at their leading ends to a knuckle which carries a wheel and each having a base thereof vertically swingably pivoted at front and rear spaced positions to a vehicle body, wherein a substantially vertical support shaft is provided to have a pair of upper and lower support arms projected therefrom, the support shaft being carried on the vehicle body through elastic members, and wherein either of front and rear portions of the respective base ends of the upper and lower control arms are connected respectively to the upper and lower support arms.
With such construction, if a load in the longitudinal direction of the vehicle is applied to a central portion of the knuckle, then the upper and lower control arms apply respective rotational moments in the same direction to the support shaft and hence, the total rotational moment received by the support shaft is large. On the other hand, if a braking force is applied to a point of contact of tire with ground, then the upper and lower control arms apply rotational moments in the opposite directions to the support shaft, so that these moments work to negate each other, resulting in a total rotational moment applied to the support shaft being zero or slight. Accordingly, even if the spring constant of an elastic member for supporting the support shaft is set at a smaller value in order to provide a larger longitudinal compliance, a larger caster rigidity can be assured during braking. This makes it possible to satisfy both the shock absorbing property during vehicle travelling on a rough road surface and the straight advancing property during braking.
The above and other objects, features and advantages of the invention will become apparent from reading of the following description of the preferred embodiments, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Drawings illustrate embodiments of the present invention, wherein
FIG. 1 is a perspective view of the whole of a wheel suspension system according to the present invention;
FIGS. 2 and 3 are sectional views taken along lines II--II and III--III in FIG. 1, respectively;
FIGS. 4 and 5 are respective plan and side views for explaining an operation when a wheel moves up a protrusion on a road surface; and
FIGS. 6 and 7 are respective plan and side views for explaining an operation during braking.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described in more detail by way of embodiments with reference to the accompanying drawings. Referring first to FIG. 1, there is shown a wheel suspension system for vehicles according to a first embodiment of the present invention, which includes a knuckle 2 for carrying a wheel 1. The knuckle 2 comprises a spindle 3 for supporting the wheel 1 through a bearing (not shown), and bifurcated arms 4 and 4' branched to upwardly and downwardly extend from a base end of the spindle 3. An upper control arm 6 and a lower control arm 7 are connected at their leading ends to the bifurcated arms 4 and 4' through ball joints 5 and 5', respectively. A caster for the wheel 1 is determined by an inclination of a straight line connecting the respective centers of the ball joints 5 and 5'.
The upper control arm 6 is diverged at its base end into a pair of front and rear arm portions 6f and 6r, while the lower control arm 7 is also diverged at its base end into a pair of front and rear arm portions 7f and 7r. The rear arm portions 6r and 7r are vertically swingably carried respectively through elastic members 10 and 11 on pivot shafts 8 and 9 which are secured to a vehicle body B so as to extend longitudinally of the body B. Both control arms 6 and 7 are suspended and resiliently biased downwardly with respect to the body B spring means not shown.
A tubular support shaft 12 is disposed in front of and adjacent the front arm portions 6f and 7f and is rotatably supported through elastic members 18, 18' on a pivot shaft 17 which has opposite ends secured to the body B and extends substantially vertically (see FIG. 3). A pair of upper and lower support arms 13 and 14 are integrally prospected rearwardly from the outer surface of the tubular shaft 12, and the front arm portions 6f and 7f are connected to the support arms 13 and 14 through ball joints 15 and 16, respectively.
Here, if an effective length of the upper control arm 6 is represented by A 1 ; an effective length of the lower control arm 7 is by A 2 ; a distance between fulcrums at the base ends of the front and rear arms 6f and 6r in the upper control arm 6 is by B 1 ; a distance between fulcrums at the base ends of the front and rear arms 7f and 7r in the lower control arm 7 is by B 2 ; an effective length of the upper support arm 13 is by C 1 ; an effective length of the lower support arm 14 is by C 2 ; a height of the connection at the fore end of the upper control arm 6 from the ground is by H 1 ; and a height of the connection at the fore end of the lower control arm 7 from the ground is by H 2 , in order to permit the wheel suspension system to fully exhibit its intended function, these dimensions will be set so as to establish the following expression: ##EQU1##
As shown in FIG. 2, a pair of elastic stoppers 19 and 20 are secured to the body B in an opposed relation with predetermined distances to laterally opposite sides of the upper support arm 13, so that rotational angle of the tubular shaft 12 is limited by the support arm 13 coming into abutment against the stoppers 19 and 20.
It is noted that the reference numeral 21 in FIG. 1 designates a knuckle arm mounted on the knuckle 2. The knuckle arm 21 may be connected to a steering mechanism if the wheel 1 is a front wheel, or otherwise it may be supported on the vehicle body if the wheel 1 is a rear wheel. An arrow A indicates the forward or advancing direction of a vehicle.
Description will now be made of the operation of this embodiment.
Referring first to FIGS. 4 and 5, suppose that the wheel 1 passes a protrusion 22 such as a pebble on a road surface G during travelling of a vehicle. When the wheel 1 gets over the protrusion 22, a rearward component F of the force applied from the protrusion 22 to the knuckle 2 is resolved into parallel force components F 1 and F 2 by the bifurcated arms 4 and 4' to act on the leading ends of the upper and lower control arms 6 and 7. Consequently, the control arms 6 and 7 receive rearward moments M 1 and M 2 and thus apply rotational moments M 3 and M 4 in the same direction to the support arms 13 and 14 of the tubular shaft 12 while deforming the elastic members 10 and 11 at the respective base ends thereof, respectively. Accordingly, the total rotational moment M3+M4 received by the tubular shaft 12 is large, and the elastic members 18 and 18' for supporting the tubular shaft 12 can be easily deformed upon receiving a large torsional force, so that both of the upper and lower control arms 6 and 7 can be relatively easily inclined rearwardly of the vehicle by the aforesaid component F of force. In this way, a large longitudinal compliance is applied to the wheel suspension system and this makes it possible to moderate an impact force from the protrusion 22 and to prevent it from being transmitted to the vehicle body.
The upward and downward movements of the front wheel 1 on passing the protrusion 22 are permitted by the vertically swinging movements of the upper and lower control arms 6 and 7 about the corresponding pivot shafts 8 and 9 and the corresponding ball joints 15 and 16.
Then, referring to FIGS. 6 and 7, suppose that the wheel 1 has been braked by the operation of a braking system (not shown) during travelling of the vehicle. When the wheel 1 has been braked, a forward moment m 1 is applied to the upper control arm 6 and a rearward moment m 2 acts on the lower control arm 7 by a frictional braking force f applied to the front wheel 1 from the road surface G. Consequently, the upper control arm 6 applies a counterclockwise rotational moment m 3 as viewed in FIG. 6 to the upper support arm 13 of the tubular shaft 12, whereas the lower control arm 7 applies a clockwise moment m 4 to the lower support arm 14 of the tubular shaft 12. In this way, the rotational moments m 3 and m 4 applied to the support arms 13 and 14 act in just opposite directions and hence, negate each other through the tubular shaft 12. Thus, the total rotational moment acting on the tubular shaft 12 becomes approximately zero under the establishment of the above-described expression (1). As a result, the upper and lower control arms 6 and 7 can be kept from being moved forwardly or rearwardly to prevent displacement of the knuckle 2 against the frictional force f of the road surface G. Therefore, even if a tire has run onto the protrusion during braking, the longitudinal compliance can be kept at a level not different from that during non-braking. This is convenient when a priority is given to the riding comfort.
A second embodiment will be described below.
A wheel suspension system according to a second embodiment is of a construction similar to that of the first embodiment, except that dimensions of the individual parts are set to satisfy the following expression: ##EQU2##
The operation of this embodiment will be described below. When the wheel 1 passes a protrusion 2 such as pebbles on the road surface G, the total rotational moment received by the tubular shaft 12 becomes large like the first embodiment and hence, a large longitudinal compliance is achieved. When the wheel 1 has been braked by the operation of the braking system during travelling of the vehicle, the total rotational moment acting on the tubular shaft 12 is small. Further, even if the upper and lower control arms 6 and 7 are moved by the action of this total rotational moment, the amounts of movements of those arms are equal to each other in accordance with the satisfaction of the above expression (2). Consequently, the caster does not vary and hence, a large caster rigidity can be obtained. This is convenient when a priority is given to the straight advancing property.
While the illustrated embodiments show support shaft 12 connected with the front arm portions 6f, 7f of the control arms 6, 7, modifications may be made to connect the shaft 12 with the rear arm portions 6r, 7r of the control arms 6, 7, instead.
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A wheel suspension system for automobiles, which comprises a pair of upper and lower control arms connected at their leading ends to a knuckle for carrying a wheel and having base ends each of which is vertically swingably pivoted respectively at front and rear spaced positions to a vehicle body, wherein a pair of upper and lower support arms are projectingly mounted on a vertical support shaft which is carried on the vehicle body through elastic members, and either of front and rear portions of respective base ends of the upper and lower control arms are connected respectively to the upper and lower support arms. This makes it possible to assure a larger caster rigidity during braking while providing a large longitudinal compliance.
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BACKGROUND OF INVENTION
This invention relates to an improved apparatus and method of analyzing the chemical structure of a specimen utilizing nuclear magnetic resonance ("NMR") techniques. A resonance domain having a selectable size is moved in a discrete cross sectional grid pattern with respect to the specimen to scan the specimen. NMR signals are generated at discrete grid locations during scanning which signals are detected and processed to form a map showing the location and an indication of the quantitative amount of selected nuclei present at such location. By suitable rearrangement of the apparatus, sagittal and frontal sectional maps may also be produced.
This invention is an improvement of the apparatus and method described in U.S. Pat. No. 3,789,832 to Raymond V. Damadian (the '832 patent). As described in the '832 patent, it was discovered that cancerous cells had chemical structures different from normal cells. A method and apparatus were described in the '832 patent of measuring certain NMR signals produced from a specimen and comparing these signals with the NMR signals obtained from normal tissue to obtain an indication of the presence, location and degree of malignancy of cancerous tissue within the specimen.
The use of NMR techniques to analyze materials including living tissue has been an active field since the issuance of the '832 patent. For example, see "Medical Imaging by NMR" by P. Mansfield and A. A. Maudsley, British Journal of Radiology, Vol. 50, pages 188-194 (1977); "Image Formation by Nuclear Magnetic Resonance: The Sensitive-Point Method" by Waldo S. Hinshaw, Journal of Applied Physics, Vol. 47, No. 8, August, 1976; "Magnetic Resonance Zeugmatography" by Paul C. Lauterbur, Pure and Applied Chemistry, Vol. 40, No. 1-2 (1974); U.S. Pat. No. 4,015,196 to Moore et al.; and U.S. Pat. No. 3,932,805 to Abe et al.
These references include discussion of various methods of analyzing a specimen utilizing NMR techniques. All of these methods, however, have a major disadvantage in that the magnetic field for generating NMR signals cannot be focused to adjust the size of the resonance domain depending on the particular user requirements which might occur, for example, when a macroscopic scan of a specimen is desired instead of a microscopic scan.
The inventor here has published several articles on the general subject of utilizing field focusing NMR techniques. See "Tumor Imaging In A Live Animal By Field Focusing NMR (FONAR)", Physiological Chemistry and Physics, Vol. 8, pages 61-65, (1976); "Field Focusing Nuclear Magnetic Resonance (FONAR): Visualization of a Tumor in a Live Animal", Science, Vol. 194, pages 1430-1432 (Dec. 27, 1976); "Nuclear Magnetic Resonance: A Noninvasive Approach to Cancer", Hospital Practice, pages 63-70 (July, 1977) and "NMR in Cancer: XVI. Fonar Image of the Live Human Body" by R. Damadian et al., Physiological Chemistry and Physics, Vol. 9, No. 1 (1977). There has also appeared an article "Damadian's Super Magnet and How He Hopes To Use It To Detect Cancer" by Susan Renner-Smith in Popular Science, pages 76-79, 120 (December, 1977).
SUMMARY OF THE INVENTION
In its broad aspects, the present invention overcomes the disadvantages of the prior art by providing a method and apparatus for producing a resonance domain of selectable size, which may be utilized in whole body scanning of a live specimen such as a human. When oscillating magnetic radiation is directed to the resonance domain NMR signals are generated characteristic of the structure of selected nuclei within the resonance domain. These NMR signals are detected, processed and displayed to provide a user with information for analyzing the chemical structure of the specimen within the resonance domain. Apparatus is provided to move the resonance domain in a cross sectional grid pattern with respect to the specimen to obtain an indication of the composition of a cross section of the specimen. Thus an improved method and apparatus are provided for noninvasively analyzing the chemical structure of a cross section of a specimen including, for example, a live mammal such as a human.
The present invention is particularly useful in cancer detection, though its use is not limited to cancer. The invention expected to be used effectively whenever diseased tissue is chemically different from normal tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be clearly understood and readily carried into effect, several preferred embodiments will now be described, by way of example only, with reference to the accompanying drawings wherein:
FIG. 1 is a schematic diagram of one embodiment for analyzing the chemical structure of a specimen, which as shown here may include a human;
FIG. 2 is a schematic diagram of field focusing coils used in the embodiment shown in FIG. 1;
FIG. 3 is a schematic diagram of the field focusing coils shown in FIG. 2 mounted on a cylindrical form;
FIG. 4 is a schematic cross section of a human chest;
FIG. 5 is a schematic diagram showing the location of the cross section shown in FIG. 4;
FIG. 6 is a NMR map obtained according to the principles of this invention of a cross section of a chest corresponding to the cross section shown in FIG. 4;
FIG. 7 is a NMR map obtained according to the principles of this invention of a cross section of a chest having a diseased left lung;
FIG. 8 is a schematic diagram of second perspective for analyzing the composition of a specimen which again may include a human as shown here;
FIG. 8A is a sectional schematic diagram of transmitter coils utilized in the embodiment shown in FIG. 8 along the section line A--A in FIG. 8.
FIG. 9 is a schematic diagram useful in describing the principle of operation of the perspective shown in FIG. 8.
FIG. 10 is a schematic perspective diagram of a third embodiment for analyzing the composition of a specimen utilizing permanent magnets;
FIG. 11 is a schematic front view of the embodiment shown in FIG. 10;
FIG. 12 is a schematic side view of the embodiment shown in FIG. 10 with one permanent magnet removed;
FIG. 13 is a schematic diagram of the embodiment shown in FIG. 10 showing the location of the various coils utilized in this embodiment;
FIG. 14A is a NMR spectrum obtained from normal muscle tissue, and
FIG. 14B is a NMR spectrum obtained from cancerous muscle tissue.
DESCRIPTION OF PREFERRED EMBODIMENT
Apparatus for analyzing the chemical structure of a cross section of a live specimen is shown in FIG. 1. A doughnut shaped magnet 30 preferably superconducting, but which may be a copper wound ambient temperature electromagnet, having a frame 31 provides a primary static magnetic field for aligning the nuclei in specimen 32, in the direction H o as shown in FIG. 1. The specimen 32 may be a human as shown in FIG. 1. Two pairs of field focusing coils 34, 34a, and 36, 36a provide a focusing static magnetic field used to adjust the primary static magnetic field configuration within the interior of the doughnut shaped magnet 30.
Field focusing coils 34, 34a, and 36, 36a are formed as shown in FIGS. 2 and 3. The coils are wound on a planar surface as shown schematically in FIG. 2. The dimensions of the field focusing coils 34, 34a, and 36, 36a are shown in FIG. 2 where "a" is the interior radius of the doughnut shaped magnet 30. The field focusing coils 34, 34a, and 36, 36a are then placed on a cylindrical form 38 which may for example be constituted of a transparent material as shown in FIG. 3. The form 38 is then placed in the interior of the doughnut shaped magnet 30 as shown in FIG. 1 and secured to the frame 31 by brackets 39.
The primary static magnetic field configuration within the doughnut shaped magnet 30 alone is well known in the art. The amplitude of the static magnetic field in the H o direction is saddle shaped with a saddle point at the origin of magnet 30. The field focusing coils 34, 34a, and 36, 36a were chosen so that when D.C. current is applied to the four field focusing coils 34, 34a, and 36, 36a in the direction as shown in FIG. 2, by D.C. sources 40, 40a, a saddle shaped static magnetic field in the direction H o is superimposed upon the saddle shaped static magnetic field provided by magnet 30 with the saddle points coinciding at the origin of magnet 30 to form a resulting static magnetic field space in the interior of magnet 30. The current level of the two D.C. sources, 40 and 40a, may be varied to adjust the sharpness of the saddle point provided by the field focusing coils 34, 34a, and 36, 36a.
The region surrounding the coincident saddle points at the origin of magnet 30 is a region of relatively uniform field strength in the direction H o . Since the sharpness of the peak at the saddle point provided by field focusing coils 34, 34a, and 36, 36a is adjustable, the region of substantially uniform field strength is also adjustable. Thus when this peak is broadened, the region of relatively uniform field strength is made larger and when the peak is made sharper the region is made smaller. This region is the resonance domain 44 in which NMR conditions will be satisfied for selected nuclei as will be described later. This region of substantially uniform field strength, the resonance domain 44, is defined as that volume where the magnetic field gradient is less than 3.9 gauss/cm.
In equipment which has been built for analyzing mammals, the strength of the static magnetic field in the direction H o at the origin of the magnet 30 is approximately 500 gauss where the operating frequency is 10 MHz for protons and the D.C. sources 40 and 40a are each providing approximately 20 amperes. The size of the resonance domain 44 is dependent upon the current supplied by D.C. sources 40 and 40a. With each of the D.C. sources 40 and 40a providing 20 amperes of current, the resonance domain 44 has a volume of approximately 1 mm 3 . In this example, the resonance domain is relatively small. By decreasing the current from D.C. sources 40 and 40a to 10 amperes, the size of the measuring volume is increased to approximately 6 mm 3 .
Nuclear magnetic resonance conditions must exist before NMR signals are generated. The nuclear magnetic resonance conditions are described according to the well known equation:
ω.sub.o =|H.sub.o |γ (1)
where:
ω o =resonance angular frequency of the selected nuclei
γ=gyromagnetic ratio for the selected nuclei and is a constant for the selected nuclei
|H o |=magnitude of static magnetic field in direction H o
The static magnetic field in the H o direction is provided by the superconducting magnet 30 and field focusing coils 34, 34a, and 36, 36a. The resonance frequency ω o is supplied by a conventional adjustable radio frequency oscillator such as included in the nuclear induction apparatus or NMR spectrometer 42 which was described in the '832 patent. The oscillator provides a radio frequency signal at its output terminal having a frequency which can be adjusted manually by a frequency selector. The radio frequency signal is directed to radio frequency coil 46 as shown in FIG. 1 via transmitter and receiver line 43 and conventional capacitor divider network 41. The capacitor divider network 41 includes two capacitors 41a and 41b for impedence matching the coil 46 to line 43 as is well known in the art. The coil 46 is positioned to surround the resonance domain 44 and is of a size to surround a cross section of specimen 32. In FIG. 1, a human is shown in a sitting position with the coil 46 positioned to surround the chest. The coil 46 is placed on a form (not shown) and mounted to a frame 45, shown schematically in FIG. 1, which is anchored to a translator beam 48 that will be described later.
For NMR conditions to exist the coil 46 must be positioned so that the direction of the oscillating magnetic field provided by coil 46 is orthogonal to H o . Since the direction of the radio frequency magnetic field provided by coil 46 is along the longitudinal axis of the 46, the coil 46 must be positioned such that the longitudinal axis is along the "Y" axis when the patient is sitting as shown in FIG. 1. (For purposes of explanation only, throughout this specification a three dimensional space has been assigned a conventional "X", "Y" and "Z" dimensional frame of reference as shown in the drawings.) If the patient is to lie prone on the translator beam 48, in the "Z" direction, a circular coil 46 could not be used and would need to be replaced with, for example, a pair of cylindrical Helmholtz radio frequency coils, each located on opposite sides of the chest and positioned so that the direction of the radio frequency field would be in the "X" or "Y" direction.
In practice, the value of |H o | at the location of the resonance domain 44 is determined by direct measurement prior to placing a specimen or patient within the magnet 30. Since two of the variables of equation (1) are now known--namely, γ for the selected nuclei and |H o |--a user may obtain a NMR signal for selected nuclei present in the resonance domain 44 if radio frequency radiation of the proper ω o frequency to satisfy equation (1) is directed to the resonance domain 44 in a direction orthogonal to H o .
The apparatus shown in FIG. 1 is used in a pulse mode of operation to analyze a specimen. In this embodiment a pulse of radio frequency energy from the oscillator in the NMR spectrometer 42 is directed to the resonance domain 44 through the coil 46. The coil 46 is then switched to a receiver mode to detect the NMR signal, if any, produced. The detected signal is transmitted to the NMR spectrometer 42 via transmitter and receiver line 43. The NMR spectrometer 42 includes a computer and memory means for storing NMR signal parameters such as intensities and relaxation times together with the spatial coordinates of the translator beam 48.
In the analytical apparatus described in the '832 patent, the detector and transmitting coils in the '832 patent were separate coils and were positioned orthogonal to one another. In the embodiment shown in FIG. 1, the receiver coil is the same physical coil as the transmitting coil. This is another way of accomplishing the same result. The reason for this is that when radio frequency radiation is injected into the resonance domain, the magnetic moment of the selected nuclei are energized from their equilibrium states parallel to the direction of H o to a higher energy state through nuclear magnetic resonance absorption to a direction orthogonal to the direction H o when viewed in the rotating frame. When the radio frequency radiation is turned off, the energized nuclei emit a radio frequency signal as they return to their equilibrium states according to a well known equation described in the '832 patent. The orientation of the receiver or detector coil relative to the transmitter coil is immaterial so long as they are orthogonal to the H o direction. In fact, the transmitter coil and the receiver coil may be the same physical coil as is the case of the above described embodiment shown in FIG. 1. When a single coil is used a pulsed mode of operation is necessary. It should be realized, however, that a continuous mode of operation would be possible by separating the transmitter and receiving coils and orienting them orthogonal to one another and orthogonal to H o .
In FIG. 1, H T designates the direction of the transmission axis and the H R designates the direction of the receiving axis.
Scanning of a cross section of the specimen 32 in the embodiment shown in FIG. 1 is accomplished by using a translator beam 48 on which the specimen 32 is placed. Drive box 49 includes motors and gears for moving the translator beam 48 in a conventional manner in an "X" direction and "Z" direction as shown in FIG. 1. The drive box 49 is automatically activated by control unit 50 in a conventional manner to move the specimen 32 with respect to the stationary resonance domain 44 in a grid pattern in a "X-Z" plane through the specimen 32. The spatial coordinates of the translator beam 48 are transmitted to the NMR spectrometer 42 as previously discussed via lead 51 connecting the control unit 50 with the NMR spectrometer 42. Thus in scanning a human specimen 32 as shown in FIG. 1, the human is moved with respect to the stationary resonance domain 44 in a grid pattern through a cross section of the human's chest. Although FIG. 1 shows apparatus for moving the specimen 32 with respect to a stationary resonance domain 44, moving the resonance domain 44 with respect to a stationary specimen 32 is also considered to be within the scope of the present invention.
EXAMPLE 1
An experiment was performed to map a cross section of a live human chest. The human was placed in the position shown in FIG. 1 with coils 46 surrounding the chest. In this measurement, hydrogen nuclei were selected to be detected. The magnet 30 was adjusted to produce 500 gauss at the origin thereof. The translator beam 48 was moved in a grid pattern so that the human was moved with respect to the resonance domain 44 in a cross sectional pattern through the 8th thoracic vertebra as shown in FIG. 5. A pictorial depiction of this cross section is shown in FIG. 4.
The frequency of the radio frequency oscillator in NMR spectrometer 42 was set to 2.18 MHz and the oscillator adjusted to provide a 10 watt pulse of radio frequency magnetic radiation over 60 microseconds and to repeat the pulse every 800 microseconds. The control unit 50 was set to move the human patient in a grid pattern in the "X-Z", plane with movement to a new grid location accomplished just prior to the transmission of the pulse of radio frequency radiation. The NMR signals generated were detected by coil 46 and transmitted via line 43 to the NMR spectrometer 42.
The NMR spectrometer 42 processed the NMR signals utilizing a Data General computer which was programmed to store values of NMR signal intensities received corresponding to each location on the grid. The Data General computer was also programmed so that upon completion of a cross sectional scan, a map was generated showing the NMR signal intensities for each location on the grid which map was then displayed on a video display tube in 16 colors. Each color corresponded to a different intensity, ranging from white to yellow to red to blue to black with white corresponding to maximum intensity. FIG. 6 shows a black and white photograph of the original 16 color video display. The top of the image is the anterior boundary of the chest wall. The left area is the left side of the chest looking downward. The hydrogen atom NMR signal intensity is coded with black assigned to zero signal amplitude, white assigned to signals of strongest intensities and intermediate grey scales assigned to intermediate intensities. Proceeding from the anterior to the posterior along the midline, the principal structure is the heart seen encroaching on the left full lung (black cavity). The left lung is diminished in size relative to the right lung (black cavity to right of midline), as it should be (see schematic of the human chest in FIG. 4 at the 8th thoracic level shown in FIG. 5). More posteriorly and slightly left of midline is a grey circular structure corresponding to the descending aorta.
In the body wall, beginning at the sternum (anterior midline) and proceeding around the ellipse, alternation of high intensity (white) with intermediate intensity (grey) could correspond to alternation of intercostal muscles (high intensity) with ribs (low intensity) as shown in FIG. 4.
EXAMPLE 2
With the apparatus of FIG. 1 set up as with Experiment 1 a map was created of a cross section through the chest of a human patient havig a known cancerous left lung. The black and white photograph of an original 16 color video display showing infiltration of disease into the left lung is shown in FIG. 6.
The top portion of the image in FIG. 6 is the anterior chest wall and the left side is the left side of the chest looking downward. The cancerous left lung is clearly visible.
In a second embodiment a resonance domain 44a of selectable size is formed by the apparatus as shown in FIG. 8. In this embodiment two identical doughout shaped magnets 51 and 52, which may again be super-conducting or copper wound ambient temperature magnets, are axially aligned and separated by a Helmholtz distance which distance is the radius of the magnets 51 and 52. It is well known that with this configuration, the magnetic field strength within the space between the two magnets 51 and 52 is substantially uniform. This field is the primary static magnetic field and the direction of this field H o is parallel to the "Z" axis of the magnet pair 51 and 52.
Field focusing coils 54, 54a, and 56, 56a provide the focusing static magnetic field and are used to adjust the size of measuring volume 44a as field focusing coils 34, 34a, and 36, 36a did with the first described embodiment. The field focusing coils 34, 34a, and 36, 36a respectively are as shown in FIGS. 2 and 3 except that the current in coils 54, 54a are reversed from the current in coils 34, and 34a respectively. These coils are placed on cylindrical form 58 which is attached to the frames of magnets 51 and 52 by brackets 59. It is known that when these coils are positioned in this manner, the direction of the magnetic field is along the "Z" axis and the gradient of the magnetic field strength between the field focusing coils 54, 54a, and 56, 56a along the "Y" axis is linear. Thus when the cylindrical form 58 is placed as shown in FIG. 8 coaxially aligned with the axes of the two magnets 51 and 52 the magnetic field produced by field focusing coils 34, 34a, and 36, 36a is in the H o direction with a linear gradient orthogonal to the "Z" axis.
The resulting static magnetic field produced by magnets 51 and 52 and field focusing coils 34, 34a, and 36, 36a in the direction H o is substantially uniform in the "X-Z" plane and has a linear gradient in the "Y" direction. This static magnetic field in the direction H o is in the static magnetic field necessary to establish NMR conditions according to equation (1).
Two transmitter radio frequency coils 60 and 62 are mounted to form 58 by brackets 59 and provide the radio frequency signal necessary for NMR conditions. These coils may be rectangular but are preferably circular as shown in FIG. 8 and are arranged orthogonal to one another with the line of intersection in the "Y" direction and intersecting the axes of the two magnets 51 and 52. The planes of each radio frequency coil 60 and 62 is tilted 45° with respect to the "X-Y" plane as shown in FIG. 8A which is a cross sectional top view of these coils along the section line A--A shown in FIG. 8. Radio frequency coils 60 and 62 are connected to radio frequency current sources 64 and 66 through conventional capacitor divider networks 61 and 63 and transmission lines 65 and 67. The capacitor divider networks 61 and 63 are provided to match the impedance of the coils 60 and 62 with the transmission lines 65 and 64, respectively. The alternating current in the two coils 60 and 62 are phased so that the rsultant of the magnetic field vectors for the coils is orthogonal to the main magnet axis (i.e. orthogonal to "Z") and lies in the illustration shown in FIG. 8 along the "X" axis. With this arrangement the maximum amplitude of the radio frequency magnetic field is along the "Y" axis with an exponential amplitude drop off from the "Y" axis. The coils 60 and 62 thus focus the oscillating magnetic energy in a pencil beam along the "Y" axis. This pencil beam will be the source of the ω o in equation (1) above. A separate cylindrical Helmholtz coil 68 operates as the receiver coil and has its magnetic axis perpendicular to "X" and "Z", that is along the "Y" axis in the illustration shown in FIG. 8. The receiver coil 68 is supported by supports (not shown) on a translator beam 48 and will move with the patient during scanning.
Reference is now made to the schematic diagram shown in FIG. 9 to illustrate the method of operation. Scanning along the "Y" axis is accomplished by merely changing the frequency of the radio frequency magnetic field. This is possible because the |H o | value changes linearly along the "Y" axis between the two pairs of field focusing coils 54, 54a, and 56, 56a. In this embodiment, the superimposed field varies, for example, from -0.50 to +0.50 gauss between the field focusing coils 54, 54a, and 56, 56a, but the range and therefore the gradient can be made larger or smaller by varying the current in the field focusing coils 54, 54a, and 56, 56a. For a particular value |H o |, for example H oi in FIG. 9, there is a particular frequency ω oi to satisfy NMR conditions for the selected nuclei. Thus to obtain a measurement at the location where the value of |H o | is H oi+1 , the frequency of the transmitter coil is adjusted to be ω oi+1 . By varying the frequency directed to transmitter radio frequency coils 60 and 62, means are provided for scanning a specimen along a pencil beam through the specimen. The range of |H o | values established by the field focusing coils 54, 54a, and 56, 56a along the "Y" axis is sufficiently small so that only the selected nuclei are energized when the frequency sources 64 and 66 are changed. Thus a user can be sure that when a particular ω oi is used only the selected nuclei at the location H oi are being resonated.
The steepness of the gradient provided by field focusing coils 54, 54a, and 56, 56a determines the size of the measuring volume 44a because with a smaller gradient there is a larger region with substantially the same magnetic field strength than with a larger gradient.
To obtain a cross sectional scan of a specimen, for example a human, the human is placed on a translator beam 48a as shown in FIG. 5. The pencil scanning beam provided by transmitter coils 60 and 62 is along "Y" axis. The beam and specimen are moved incrementally along the "X" axis by a conventional drive box 48a and drive control unit 50a after a complete scan along the pencil beam along the "Y" axis is completed. Thus a cross sectional scan of a slice perpendicular to the "Z" axis in this illustration may be achieved. At each point on the cross sectional grid the detector or receiver coil 68 will detect any NMR signal generated. The intensity or any other parameter of the signal together with the corresponding position of the resonance domain 44a is stored in a computer memory located in the NMR spectrometer 42 connected to the receiver coil 68 through a transmission line 70 and capacitor divider network 71. These intensity values are later processed to form a cross sectional grid of values in an "X-Y" plane through the specimen to provide a map showing the location and intensity of the signal received at each location on the grid.
Although structure is shown in FIG. 8 for moving the specimen 32 with respect to a stationary pencil of transmitted radio frequency energy, it is considered that structure may be incorporated for rotating the field focusing coils 54, 54a, and 56, 56a; the transmitter coils 60 and 62; and the receiver coil 68 about the "Z" axis on a stepped bases after a complete scan along the pencil beam to complete a map of values utilizing a radial sweep pattern. The pencil beam would be rotated through 180° to obtain a complete cross sectional scan of a specimen. This is also considered to be within the scope of the present invention.
In addition, depending on the geometry of the specimen to be analyzed the direction of the magnetic axis of transmitter coils 60 and 62 (H T ) and direction of the magnetic axis of receiver coil 68 (H R ) in FIG. 8 may be reversed by repositioning the transmitting coils 60 and 62 and the receiving coil 68 so long as H T , H R and H o are mutually orthogonal. In the particular configuration shown in FIG. 8, it is preferred that the human patient be positioned to lie on his back, since the length of the pencil beam provided by transmitter coils 60 and 62 which extends through the specimen is minimized. However, other variations are contemplated and considered to be within the scope of the invention.
A third embodiment embodying the principles of this invention is shown in FIGS. 10-13. In this embodiment the static magnetic field in the H o direction is provided by permanent magnets 76 and 78. Pole faces 72 and 74 are mounted on the magnets 76 and 78 to concentrate flux. The configuration of the static magnetic field between permanent magnets 76 and 78 is well known to be substantially uniform.
The specimen 32 to be analyzed which again may be, for example, a human is positioned on a translator beam 48c associated again with drive box 49c and control unit 50c within the space between magnets 76 and 78. Field focusing coils 80, 80a, and 82, 82a correspond to field focusing coils 54, 54a, and 56, 56a of the second embodiment shown in FIG. 8 and provide a linear gradient of the static field in the H o direction along the "Y" axis.
Transmitter coils 86 and 88 correspond to transmitter coils 60 and 62 of the embodiment shown in FIG. 8. In this embodiment, the line of intersection of the transmitter coils 86 and 88 is along the "Y" axis and each of the transmitter coils 86 and 88 are orthogonal to the other and tilted 45° to the "Y-Z" plane. The receiver coil 90 corresponds to receiver coil 68 in the embodiment shown in FIG. 8. In FIGS. 11-14, the connection of these coils to sources and the NMR spectrometer are not shown since they are the same as the embodiment shown in FIG. 8.
The apparatus shown in FIGS. 10-13 functions in the same manner as the apparatus shown in FIG. 8 and is similar to such apparatus with the exception that here permanent magnets 76 and 78 replace the Helmholtz pair of magnets 51 and 52 as was the case with the embodiment shown in FIG. 8. The magnetic directions of transmitter coils 86 and 88 (H T ) and the receiver coil 90 (H R ) are still orthogonal and both are still orthogonal to H o . To accommodate a human patient, the coils had to be rearranged; however, the principle of operation in both embodiments is identical.
The direction of H o in this third embodiment is along the "X" axis instead of the "Z" axis. H R is in the "Y" direction, and H T is in the "Z" direction, thus H o , H R and H T are all orthogonal to one another. A resonance domain 92 is located on a pencil beam provided by the transmitter coils 86 and 88 as was the case with the embodiment shown in FIG. 8. Since the pencil beam is located on the line of intersection of the planes of the two transmitter coils 86 and 88, the pencil beam lies along the "Y" axis.
Scanning is accomplished as with the embodiment shown in FIG. 8 by scanning along the pencil beam in the "Y" direction and translating the specimen or patient 32 in the "X" direction. This provides scanning in the "X-Y" plane. The NMR signal intensity is measured at each point on the pencil beam at each discrete position of the pencil beam with respect to the specimen. Again, the values detected are stored, processed and displayed to show a cross sectional map of the specimen showing intensities of NMR signal at each location on the cross section of the specimen.
With any of the three embodiments above described, a user may process the NMR signal obtained and determine a nuclear magnetic value which may be, for example, the intensity of the NMR signal obtained representing the degree of presence of the selected nuclei within the resonance domain, an amplitude versus frequency spectrum indicative of the atomic combinations of the selected nuclei within the resonance volume; the spin-lattice relaxation time; the spin-spin relaxation time; spin-mapping values of selected nuclei indicative of the degree of organization of the selected nuclei within the resonance domain. All of these nuclear magnetic resonance values obtained may be displayed for analysis by a user and cross sectional maps may be made. In detecting cancerous tissue in mammals it is preferred that the selected nuclei be, for example, P 31 , K 39 , Na 23 , H 1 , C 13 , N 15 , N 14 and O 17 . However, this apparatus may be used in detecting and analyzing other diseases in tissue when selected nuclei in the diseased tissue has a different chemical organizational structure from the selected nuclei of normal non-diseased tissue.
In forming NMR amplitude versus frequency spectra, a pulse mode of operation may be used with the above described three embodiments wherein the transmitted pulse injected into the resonance domain has a band of frequencies. The resulting amplitude versus time NMR signal detected by the receiver coils is directed to NMR spectrometer 42 having a computer programmed to perform a Fast Fourier Transform on the data received to develop an amplitude versus frequency spectrum.
Examples of such amplitude versus frequency spectra which were obtained using the first embodiment are shown in FIGS. 14A and 14B.
EXAMPLE 3
FIG. 14A shows a P 31 NMR spectrum obtained non-invasively for normal muscle tissue and FIG. 14B shows on P 31 NMR spectrum obtained non-invasively for malignant muscle. The operating frequency of the radio frequency oscillator was 100 MHz and the bandwidth of the transmitted pulse was 5,000 Hz and from 100 MHz-1000 Hz to 100 MHz+4,000 Hz and the pulse interval was 10 seconds. The resulting spectrum was the 256 averaged free induction decay peak positions based on the mean positions of 8 separate experiments. Each peak is the resonance from phosphorus for a different phosphorus containing molecule except in the case of adenoisine tri-phosphate (ATP) where three resonances (Peaks D, E and F in FIG. 15A) are seen for the molecule, one for each of three phosphates. Peak A in FIGS. 14A and 14B is the phosphorus resonance of a sugar phosphate positioned at -3.9 ppm in normal muscle and -4.3 ppm in malignant muscle (a difference of 40 Hz at the operating frequency of 100 MHz). Ppm is an abbreviation for parts per million and here is used to locate the frequency positions of peaks with respect to the operating frequency. One ppm corresponds to a frequency 100 Hz above the operating frequency of 100 MHz and -1 ppm corresponds to a frequency 100 Hz less than the operating frequency 100 MHz. Peak B in FIGS. 14A and 14B is the phosphorus resonance for the inorganic salts of phosphorus positioned at -1.7 ppm in normal muscle and -2.4 ppm in malignant muscle (a difference of 70 Hz). Peak C in FIG. 14A is creatine phosphate (absent in cancer), and Peaks D, E, F in FIG. 14A are the three phosphates of ATP (absent in cancer). Thus by noting the absence of certain peaks and the shift of certain peaks in a NMR spectrum obtained for tissue located within the resonance domain as compared with a NMR spectrum for malignant tissue, malignant tissue may be detected and located non-invasively.
Depending on the physical constraints caused by the geometry of the specimen to be measured, the receiver coil in all three embodiments may be a circular type coil if it can surround the specimen or be a split cylindrical Helmholtz coil if it is not practical to physically position the coil around the specimen.
Furthermore, in all three embodiments, the tranmitter and receiver coils may be combined provided a pulse mode of operation is utilized as explained above in conjunction with the first embodiment.
All such variations are considered to be within the scope of the present invention.
A continuous mode of operation could also be used with the three embodiments described. However, in this mode of operation, separate transmitter and receiver coils are required which by necessity must be orthogonal to the direction H o of the static magnetic field. In the continuous mode or high resolution mode, the transmitter operates continuously as either its frequency is gradually varied or the strength of the static magnetic field in the H o direction is varied. Under these conditions and in a specimen where the selected nuclei (for example, hydrogen) exist in a variety of combinations with other atoms, the different combinations would be seen as resonance peaks. See for example FIGS. 14A and 14B. Each resonance peak represents a different wavelength for NMR absorption and is caused by the fact that different atomic combinations with the selected nuclei alter the configuration of the electron cloud surrounding the nucleus and consequently the net magnetic moment of the electron cloud. Thus, the frequency at which resonance occurs also varies with the various combinations of other nuclei with the selected nuclei. The different resonant frequencies appear as resonance peaks on an amplitude versus frequency spectrum.
As described above in conjunction with Example 3, an amplitude versus frequency spectrum can also be obtained in the pulse mode by transmitting a pulse of a predetermined bandwidth to the resonance domain; detecting the resulting NMR signal; and using a Fast Fourier Transform to generate the spectrum. The continuous mode obtained by varying the frequency of the transmitter with time provides a method of obtaining an amplitude versus frequency spectrum directly without the need of using a Fast Fourier Transform.
It should be understood that the above three embodiments could be adapted to measure NMR signals for multiple selected nuclei by, for example, mounting multiple receiver coils, one for each of the separate types of selected nuclei on top of one another. The transmitter coil would be pulsed in a timed sequence providing the necessary radio frequency signal required for NMR conditions for the first selected nuclei then the second selected nuclei, etc. Other variations such as providing electronic circuitry for detecting the transmitted signal and which would eliminate the need for multiple receiver coils is contemplated by and is within the scope of this invention. The detected NMR signals could then be processed and displayed on multiple video displays.
The present invention provides a much needed method and apparatus for determining the chemical structure of a specimen including apparatus for making a macroscopic scan or microscopic scan of the specimen. It is understood that many modifications of the structure of the preferred embodiments will occur to those skilled in the art, and it is understood that this invention is to be limited only by the scope of the following claims.
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An improved apparatus and method for analyzing the chemical and structural composition of a specimen including whole-body specimens which may include, for example, living mammals, utilizing nuclear magnetic resonance (NMR) techniques. A magnetic field space necessary to obtain an NMR signal characteristic of the chemical structure of the specimen is focused to provide a resonance domain of selectable size, which may then be moved in a pattern with respect to the specimen to scan the specimen.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Art
[0002] The present invention relates to a process for preparing N-methylated melamines characterized by heating melamine (2,4,6-triamino-1,3,5-triamine) with methylamine (monomethylamine) in the presence of an acid catalyst under pressure to substitute at least one amino group of the melamine by methylamino group(s).
[0003] Specifically, the reaction of melamine and methylamine in the presence of an acid catalyst leads N-methylated melamines including 2,4-diamino-6-methylamino-1,3,5-triazine (mono-type), 2-amino-4,6-bis(methylamino)-1,3,5-triazine (bis-type) and 2,4,6-tris(methylamino)-1,3,5-triazine (tris-type) as desired compounds.
[0004] N-methylated melamines are useful compound groups that are used widely as various fine chemical intermediates for agricultural chemicals, medicines, dyes, paints and the like, as forming components for various resin materials, in particular an aminoplast, and as a flame retardant
[0005] 2. Description of the Related Art
[0006] As methods for preparing N-alkylated melamines, synthetic methods by reacting cyanuric chloride with an alkylamine are reported (J. Amer. Chem. Soc., 73, 2984 (1951) and U.S. Pat. Nos. 5,124,379 and 4,886,882). The synthetic methods require expensive cyanuric chloride, a plurality steps for synthesizing mono-type and bis-type of N-alkylated melamines and further disposal of hydrochloric acid in post-treatment
[0007] Further, a synthetic method disclosed in U.S. Pat. No. 2,228,161 (corresponding to GB Patent No. 496,690) is also known. The synthetic method comprises reacting melamine with hydrochloride of an alkylamine. As the reaction requires to be carried out in a state of solid by using hydrochloric acid, an amount of reactants to be treated is very large. In addition, the reaction needs countermeasures against corrosion in an apparatus and lowering in quality of products due to the use of the hydrochloride in a high temperature. Further, the reaction necessitates disposal of hydrochloric acid in post-treatment. The above-mentioned U.S. Pat. No. 2,228,161 discloses a method as a synthetic method of N-methylated melamines in which melamine and methylamine hydrochloride are reacted at 200° C. on a solid phase. The patent publication reports that the yield of 2-amino-4,6-bis(methylamino)-1,3,5-triazine (bis-type) is 50 to 55% based on tri-N-methylated melamines and that a small amount of 2,4,6-tris(methylamino)-1,3,5-triazine (tris-type) is obtained.
[0008] It is known that the yield by a method in which methylol melamine is reduced is low and that the method requires treatment of polymers that are generated as by-product.
SUMMARY OF THE INVENTION
[0009] The present invention provides a process for preparing N-methylated melamines. In detail, the present invention provides a process for preparing N-methylated melamines that is carried out in simple steps by using melamine and methylamine that are inexpensive raw materials and that can control the proportion of mono-type, bis-type and tris-type in prepared N-methylated melamines.
[0010] A first embodiment of the present invention is a process for preparing N-methylated melamines comprising reacting by heating melamine with methylamine in the presence of an acidic catalyst under-pressure to substitute at least one amino group of the melamine by methylamino group.
[0011] The first embodiment includes the following preferred embodiments:
[0012] 1) wherein a temperature of 160° to 250° C. is selected as a reaction temperature; and
[0013] 2) wherein the reaction is carried out with removal of ammonia generated in the course thereof and thereby increasing the proportion of N-methylated melamines of tris-type and bis-type.
[0014] A second embodiment of the present invention is a process for preparing N-methylated melamines comprising reacting by heating melamine, methylamine and a solvent in the presence of an acidic catalyst under pressure to substitute at least one amino group of the melamine by methylamino group.
[0015] The second embodiment includes the following preferred embodiments:
[0016] 1) wherein the solvent is one or more of trialkykamines;
[0017] 2) wherein a temperature of 160° to 250° C. is selected as a reaction temperature; and
[0018] 3) wherein the reaction is carried out with removal of ammonia generated in the course thereof and thereby increasing the proportion of N-methylated melamines of tris-type and bis-type.
[0019] The present invention can provide a process for synthesizing N-methylated melamines by using melamine and methylamine that are inexpensive raw materials. In addition, the present invention enables the proportion of substituted types of N-methylated melamines to control by selecting the amount of methylamine used and carrying out removal of ammonia as generated. In particular, the yield of 2,4,6-tris(methylamino)-1,3,5-triazine (tris-type) exceeds 80%.
[0020] Further, as the above-mentioned reaction must be carried out under a high pressure and at a high temperature, the selection of material of reactor used is in problem. However, the present inventors found out that the use of trialkylamines as a solvent can avoid corrosion of reactors in the course of the reaction and the application of high pressure. Consequently, reactors (e.g., an autoclave) are prevented from corrosion, and it makes possible to carrying out the reaction at a temperature of 190° C. and a pressure of 7 MPa or less although the pressure is selected depending on the amount of solvent used. Accordingly, the present invention permits reactors designated for using under a low pressure to be utilized.
[0021] Also, the present invention is excellent in that N-methylated melamines are useful compounds conferring flexibility on melamine resins and that N-methylated melamines have high solubility in water, and mix with melamines optionally and thereby being able to polymerize with formalin.
[0022] For example, the conferring of flexibility on melamine resins makes clear from a flex test (Evaluation Example 2 in WO97/11102) in which an impregnated paper is prepared by impregnating a resin solution obtained by adding tris-type resin to melamine resin, the impregnated paper is processed to a laminated cured sheet and the sheet is evaluated.
[0023] Melamine resins prepared from melamine are very hard and therefore have brittleness. When flexibility is to be conferred on the melamine resins for improving the brittleness thereof, even a mixture of mono-type, bis-type and tris-type of N-methylated melamines can be used.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Each of the above-mentioned embodiments is specifically described in the followings.
[0025] After melamine, an acidic catalyst and a solvent are charged into an autoclave, a bomb charged with methylamine is connected to the autoclave, and the autoclave is cooled with dry ice-acetone refrigerant. Then, methylamine in a state of gas is blown into the autoclave from the bomb while weighing with a balance. After the predetermined amount of methylamine is blown into, charging is completed.
[0026] Thereafter, the reaction is carried out at a temperature of 190° C. by heating the autoclave
[0027] The reaction can be carried out at a temperature between 140° C. and 300° C. However, when the temperature is high, side reactions occur and thereby yield lowers, and further reaction pressure increases. A temperature between 160° C. and 250° C. is preferable, and a temperature between 160° C. and 200° C. is more preferable. The reaction is an equilibrium reaction in which methylamine is converted to ammonia, and comes to equilibrium in about 2 hours in a case where the reaction is carried out at 190° C. When ammonia is removed from the reaction system, the equilibrium shifts and the rate of reaction increases more and more.
[0028] The proportion of the substituted reaction products can be relatively controlled, and tris-type can be produced in a yield of about 40 to 80%.
[0029] The pressure on reaction is 6 to 8 MPa at 170° C. or 11 to 12 MPa at 190° C. in a case where no solvent is used. On the other hand, in a case where solvents are used, for example when trimethylamine is used as a solvent in an amount of 50 parts by weight based on 100 parts by weight of melamine, the pressure is 4 to 6 MPa. It is preferable to use solvents from the viewpoint of the structure of apparatus (reactor) and safety.
[0030] The amount of methylamine is 30 to 5000 parts by weight based on 100 parts by weight of melamine. The more methylamine is used, and the more tris-type is produced. On the other hand, the less it is used, and the more mono- or bis-type (low substituted product) is produced. In addition, methylamine acts also as a solvent for dissolving melamine although this depends on the amount of trialkylamines used. Therefore, the rate of reaction makes low when the amount of methylamine is too small.
[0031] Instead of methylamine, alkylamines (monoalkylamines) having carbon atoms of 4 or less may be used similarly to methylamine. The reaction pressure makes lower with an increase in carbon atoms of alkylamines, and thereby the treatment of reaction makes easier.
[0032] As the acidic catalyst, a salt of a strong acid with a weak base, a salt of a strong acid with a strong bass, an acid or the like can be used.
[0033] The salt of a strong acid with a weak base includes, for example ammonium chloride (sublimed at 337° C.), ammonium sulfate, ammonium phosphate and the like. Also, a quaternary ammonium salt can be used as an acidic catalyst. Taking into account separation of an acidic catalyst in post-treatment, it is preferable to use a quaternary ammonium salt compound having long-chain alkyl group, such as trioctylmethyl ammonium chloride (TOMAC).
[0034] The salt of a strong acid with a strong base includes, for example sodium chloride, potassium chloride and the like.
[0035] The acid includes, for example hydrofluoric acid, hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, sulphamic acid and the like. These acids become salts in a reaction system.
[0036] The acidic catalyst to be used is determined from the viewpoint of the corrosion of autoclaves and the rate of reaction. When trialkylamines are used as a solvent ammonium chloride is more preferable.
[0037] The amount of the acidic catalyst may be 0.1 to 30 parts by weight based on 100 parts by weight of melamine. In order to facilitate the separation of the catalyst and products, the amount is preferably 1 to 5 parts by weight
[0038] Trialkylamines as a solvent includes, for example trialkylamines one alkyl group of which has carbon atoms of 2 to 10. Triethylamine is preferable from the viewpoint of economic efficiency. The amount of the solvent is 10 to 2000 parts by weight, and preferably 50 to 500 parts by weight based on 100 parts by weight of melamine. When the solvent is used in a more amount, the pressure on reaction lowers. However, in such a case the rate of the reaction lowers and thereby the productivity deteriorates.
[0039] The removal of ammonia can be carried out by opening gradually a valve of an autoclave to release slowly it, and more efficiently by rectifying under pressure.
[0040] The purification of products from a reaction mixture can be carried out by adding gradually the reaction mixture dissolved by heating into a solvent to isolate desired products as slurry. The solvent includes, for example esters, such as ethyl acetate, alcohols, such as methanol or ethanol, ethers, such as cellosorves, dioxane, ethyl ether or isopropyl ether, acetonitrile, DMF, DMSO and NMP, and so on. These solvents may be used alone or in a mixture.
[0041] In addition, the slurry obtained by feeding these solvents into an autoclave and then cooling may be filtered to be isolated.
[0042] Further, it is easy to purify and isolate the desired products even by solid distillation. In this case, a catalyst to be used should be one having a very high boiling point and high thermal stability.
EXAMPLES
[0043] Hereinafter, the present invention is described more specifically on the basis of examples to which the present invention is not limited.
[0044] In all of the following Examples, the quantitative determination of products was carried out as follows. First of all, products to be determined were previously synthesized as preparations as indicated in Reference Examples (for example, a method for synthesizing melamine derivatives was processed according to those disclosed in J. Amer. Chem. Soc., 73, 2984 (1951) and U.S. Pat. Nos. 5,124,379 and 4,886,882). Next, a calibration curve was made based on products isolated as pure products and internal standards. Finally, the each amount of products in reaction products was determined by the internal standard quantitative method with high performance liquid chromatography.
[0045] The analytical conditions of high performance liquid chromatography used were as follows:
[0046] (Analytical Conditions)
[0047] Eluting solution: H 2 O/CH 3 OH=750/250 (v/v);
[0048] Detection method: UV 220 nm;
[0049] Column: Inertsil Ph 150 mm×4.6 mm φ provided by GL Science Co.;
[0050] Flow rate: 1.0 ml/min.;
[0051] Analytical temperature: 50° C.; and
[0052] Internal standard: Parachloroaniline.
[0053] (Analytical Conditions: Standard Retention Time (min))
[0054] 1) Melamine; 3.44;
[0055] 2) 2,4-diamino-6-methylamino-1,3,5-triazine (mono-type): 4.06;
[0056] 3) 2-amino-4,6-bis(methylamino)-1,3,5-triazine (bis-type): 5.75;
[0057] 4) 2,4,6-tris(methylamino)-1,3,5-triazine (tris-type): 10.10; and
[0058] 5) Parachloroaniline (internal standard): 20.58.
[0059] 1,3,6-triazine derivatives as preparations were synthesized according to the following Reference Examples.
REFERENCE EXAMPLE 1
Synthesis of 2,4-diamino-6-chloro-1,3,5-triazine
[0060] After 184.5 g (1.0 mol) of cyanuric chloride was dissolved into 800 ml of acetonitrile at a room temperature, the resulting mixture was cooled to 0° C. and 303.7 g (5.0 mol) of 28% aqueous solution of ammonia was added dropwise in 2 hours thereto under vigorous stirring while the reaction temperature was maintained at 10° C. or less. After the adding dropwise was completed, the cooling was stopped, and the mixture was stirred for 1 hour at a room temperature, and then gradually heated to 45° C., and reacted for further 4 hours. After cooling, products were filtered off, and washed with a large amount of water. The resulting filter residue was dried in vacuo at 50° C. for 6 hours to give 115 g (yield: 79%) of the titled compound.
REFERENCE EXAMPLE 2
Synthesis of 2,4-diamino-6-methylamino-1,3,5-triazine
[0061] A mixed solution comprising 14.5 g (0.1 mol) of 2,4-diamino-6-chloro-1,3,5-triazine synthesized in Reference Example 1 and 31.1 g (0.4 mol) of 40% aqueous solution of methylamine was heated under stirring and reacted finally at the reflux temperature thereof for 6 hours. After cooling the reacted solution, products were filtered off, and washed with cold water. The resulting filter residue was dried in vacuo at 70° C. for 6 hours to give 9.1 g (yield: 65%) of the titled compound. Melting point: 269° C.
REFERENCE EXAMPLE 3
Synthesis of 2,4,6-tris(methylamino)-1,3,5-triazine
[0062] After 18.5 g (0.1 mol) of cyanuric chloride was dissolved into 150 ml of acetonitrile, the resulting mixture was cooled to 0° C. and 15.5 g (0.2 mol) of 40% aqueous solution of methylamine was added dropwise in 1 hour thereto under stirring in such a manner that the reaction temperature did not exceed 5° C. While further stirring, 100 ml of water including 20.0 g (0.2 mol) of potassium hydrogencarbonate was added dropwise at the same temperature. Thereafter, the reaction temperature was gradually raised, and stirred at 45° C. for 8 hours. After confirming that an inversion to 2,4-bis(methylamino)-6-chloro-1,3,5-triazine was completed, the reaction solution was cooled and products were filtered off. The filter cake was fully washed with water, and then the resulting 2,4-bis(methylamino)-6-chloro-1,3,5-triazine was suspended into 100 ml of water, and 31.1 g (0.4 mol) of 40% aqueous solution of methylamine was added, and further heated under reflux for 6 hours. After cooling, the deposited crystal was filtered, washed fully with water and dried to give 13.1 g (yield: 78%) of the titled compound. Melting point: 133° C.
REFERENCE EXAMPLE 4
[0063] 2-amino-4,6-bis(methylamino)-1,3,5-triazine was synthesized similarly to Reference Example 3. Melting point 291° C.
Example 1
[0064] After 5 g of melamine and 0.1 g of ammonium chloride as an acidic catalyst were charged Into a 100 ml glass autoclave, a bomb charged with methylamine was connected to the autoclave, and the autoclave was cooled with dry ice-acetone refrigerant. After bubbling from the refrigerant was ceased, 10 g of methylamine in a state of gas was blown into the autoclave from the bomb while weighing with a balance.
[0065] Then, the temperature in the autoclave was kept at 190° C. by heating the autoclave. In the course of it, an exothermic reaction occurred from ca. 170° C. in the autoclave, and thereby the temperature was raised by needy 10° C.
[0066] Thereafter, the temperature was raised to 190° C., and thereby the pressure was raised to 10 MPa. The reaction mixture was reacted at 190° C. for 2 hours.
[0067] After the reaction was completed, the autoclave was cooled, gaseous materials in the autoclave were removed out of the system by opening a valve, and the autoclave was opened.
[0068] The mixture in the autoclave was dissolved in water, and the quantitative analysis thereof was carded out. As a result of it, the degree of conversion of melamine as a raw material was 94.1%, and as products, 2,4-diamino-6-methylamino-1,3,5-triazine, 2-amino-4,6-bis(methylamino)-1,3,5-triazine and 2,4,6-tris(methylamino)-1,3,5-triazine were prepared in yield of 21.4%, 30.4% and 41.3%, respectively.
Example 2
[0069] After 31 g of melamine and 0.5 g of ammonium chloride as an acidic catalyst were charged into a 200 ml glass autoclave, a bomb charged with methylamine was connected to the autoclave, and the autoclave was cooled with dry ice-acetone refrigerant After bubbling from the refrigerant was ceased, 96 g of methylamine in a state of gas was blown into the autoclave from the bomb while weighing with a balance.
[0070] Then, the temperature in the autoclave was kept at 190° C. by heating the autoclave. In the course of it, an exothermic reaction occurred from ca. 170° C. in the autoclave, and thereby the temperature was raised by nearly 10° C. When the temperature was 170° C., the pressure was 6 MPa.
[0071] Thereafter, the temperature was raised to 190° C., and thereby the pressure was raised to 11.5 MPa. The reaction mixture was reacted at 190° C. for 1 hour. In this reaction, a valve of the autoclave was loosened, and thereby gas was let out intermittently and gradually, and the reaction was completed at a reaction pressure of 6 MPa. The temperature of the autoclave was raised by a few ° C. each time gas was let out.
[0072] After the reaction was completed, the autoclave was cooled, gaseous materials in the autoclave were removed out of the system by opening a valve, and the autoclave was opened. The color of the interior of autoclave turned into brown. Therefore, corrosion of the autoclave was confirmed.
[0073] The mixture in the autoclave was dissolved in water, and the quantitative analysis thereof was carried out. As a result of it, the degree of conversion of melamine as a raw material was 99.8%, and as products, 2,4-diamino-6-methylamino-1,3,5-triazine, 2-amino-4,6-bis(methylamino-1,3,5-triazine and 2,4,6-tris(methylamino)-1,3,5-triazine were prepared in yield of 0.9%, 16.1% and 81.0%, respectively.
Example 3
[0074] After 31 g of melamine 10 g of triethylamine as a solvent and 0.5 g of ammonium chloride as an acidic catalyst were charged into a 200 ml stainless steel autoclave, a bomb charged with methylamine was connected to the autoclave, and the autoclave was cooled with dry ice-acetone refrigerant After bubbling from the refrigerant was ceased, 63 g of methylamine in a state of gas was blown into the autoclave from the bomb while weighing with a balance.
[0075] Then, the temperature in the autoclave was kept at 190° C. by heating the autoclave. In the course of it, an exothermic reaction occurred from ca. 170° C. in the autoclave, and thereby the temperature was raised by nearly 10° C. When the temperature was 170° C., the pressure was 6 MPa.
[0076] Thereafter, the temperature was raised to 190° C., and thereby the pressure was raised to 9 MPa. The reaction mixture was reacted at 190° C. for 1 hour.
[0077] After the reaction was completed, the autoclave was cooled, gaseous materials in the autoclave were removed out of the system by opening a valve, and the autoclave was opened. No corrosion of the autoclave was confirmed.
[0078] The mixture in the autoclave was dissolved in water, and the quantitative analysis thereof was carried out. As a result of it, the degree of conversion of melamine as a raw material was 96.1%, and as products, 2,4-diamino-6-methylamino-1,3,5-triazine, 2-amino-4,6-bis(methylamino)-1,3,5-triazine and 2,4,6-tris(methylamino)-1,3,5-triazine were prepared in yield of 16.5%, 38.2% and 41.0%, respectively.
Example 4
[0079] Except that 4 g of triethylamine as a solvent and 0.2 g of sodium chloride as an acidic catalyst were used, the reaction was carried out similarly to the procedures in Example 1. conversion or melamine as a raw material was 89.3%, and as products, 2,4-diamino-6-methylamino-1,3,5-triazine, 2-amino-4,6-bis(methylamino)-1,3,5-triazine and 2,4,6-tris(methylamino)-1,3,5-triazine were prepared in yield of 30.9%, 35.8% and 21.7%, respectively.
Example 5
[0080] Except that 0.2 g of ammonium sulfate and 0.2 g of potassium chloride as an acidic catalyst were used, the reaction was carried out similarly to the procedures in Example 1
[0081] The mixture in the autoclave was dissolved in water, and the quantitative analysis thereof was carried out. As a result of it, the degree of conversion of melamine as a raw material was 98.8%, and as products, 2,4-diamino-6-methylamino-1,3,5-triazine, 2-amino-4,6-bis(methylamino)-1,3,5-triazine and 2,4,6-tris(methylamino)-1,3,5-triazine were prepared in yield of 17.0%, 49.3% and 32.0%, respectively.
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The present invention provides a process for preparing N-methylated melamines in simple steps by using inexpensive raw materials in such a manner that the proportion of mono-type, bis-type and tris-type of the N-methylated melamines as prepared can be controlled. The process comprises reacting by heating melamine with methylamine in the presence of an acidic catalyst under pressure to substitute at least one amino group of the melamine by methylamino group
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RELATED APPLICATIONS
This application is based on Provisional Application Ser. No. 60/683,584, filed on May 23, 2005, and claims priority therefrom. The provisional application is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
The present invention relates generally to tissue cutting members for tissue removing devices such as biopsy devices and the like.
BACKGROUND OF THE INVENTION
In diagnosing and treating certain medical conditions, such as potentially cancerous tumors, it is usually desirable to perform a biopsy, in which a specimen of the suspicious tissue is removed for pathological examination and analysis. In many instances, the suspicious tissue is located in a subcutaneous site, such as inside a human breast. To minimize surgical intrusion into the patient's body, it is desirable to be able to insert a small instrument into the patient's body to access the targeted site and to separate the biopsy specimen therefrom.
Tissue cutting members currently used with biopsy devices have a variety of problems. Often tissue becomes trapped between the cutting member and the shaft within which the cutting member is disposed. Also many cutting members currently available in the art are not suitable for effectively separating tough or hard tissue from the target site in a patient's body.
There is need in the art for cutting members with improved efficiency for separating tissue specimens from a target location in a patient's body.
SUMMARY OF THE INVENTION
This invention is directed to tissue cutting members for devices for separating tissue from a target site within a patient's body. More particularly, the invention is directed to tissue cutting members and biopsy devices using such tissue cutting members for the separation of a tissue specimen from supporting tissue at the targeted site within a patient. A suitable biopsy device having a cannula which may be utilized with a tissue cutting member having features of the invention is described in co-pending application Ser. No. 11/014,413, filed on Dec. 16, 2004.
A tissue cutting member embodying features of the invention includes a distal tubular portion having a distal tip with an outer tissue cutting edge, an inner tissue receiving aperture, and a longitudinal axis. Preferably the distal tip of the distal tubular portion has a beveled front face with a leading edge and a trailing edge.
The tubular distal tubular portion has a longitudinally oriented opening in a wall of the distal tubular portion with an open distal end which opens to the inner tissue receiving aperture, and a closed proximal end. The distal tubular portion of the tissue cutting member has at least a second opening in a wall of the tubular portion and preferably a plurality of openings circumferentially spaced from the open ended slot about the longitudinal axis and preferably the centers of these openings are circumferentially located at about 90°, 135°, or 180° from a midpoint of the longitudinally oriented opening. The one or more circumferentially spaced openings may be one of a variety of shapes, for example, a rectangular shape, a circular shape, or an elongated shape such as an oval or elongated slot. One or more of the openings in the distal tubular portion may be of one shape and one or more of the other openings may be of another shape. The openings allow for the vacuum to be maintained within the biopsy device when the cutting member is cutting and provide stress relief, facilitating radial expansion and/or contraction.
The distal tubular portion preferably has a flared distal section with a proximal end and a distal end, and a cylindrically shaped proximal section with a proximal end and a distal end. The open distal end of the longitudinally oriented opening facilitates the flaring of the flared distal section. The flared distal section ensures that the outer tissue cutting edge of the distal tubular portion engages an inner tissue cutting edge of a tissue receiving aperture in the cannula of the biopsy device to cleanly sever the tissue specimen from the supporting tissue and to provide a better tissue specimen for pathological examination.
These and other advantages of the invention will become more apparent from the following detailed description of the invention and the accompanying exemplary drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the proximal portion of an elongated probe member of a biopsy device that has features of the invention.
FIG. 2 is an enlarged perspective view of a distal portion of the elongated probe shown in FIG. 1 illustrating a tissue cutting member embodying features of the invention disposed within the probe.
FIG. 3A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two openings with a rectangular shape.
FIG. 3B is a perspective view of the distal tubular portion shown in FIG. 3A that has been rotated 180° from the view of FIG. 3A .
FIG. 3C is an elevational view of the embodiment of the device shown in FIG. 3A .
FIG. 3D is a longitudinal cross sectional view of the distal tubular portion taken along lines 3 D- 3 D in FIG. 3C .
FIG. 3E is a transverse cross sectional view of the distal tubular portion taken along lines 3 E- 3 E in FIG. 3C .
FIG. 3F is a transverse cross sectional view of the distal tubular portion taken along lines 3 F- 3 F.
FIG. 4A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two circular openings.
FIG. 4B is a perspective view of the distal tubular portion shown in FIG. 4A that has been rotated 180° from the view of FIG. 4A .
FIG. 5A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two circular openings and one opening which is an elongated longitudinally oriented slot.
FIG. 5B is a perspective view of the distal tubular portion shown in FIG. 5A that has been rotated 180° from the view of FIG. 5A .
FIG. 6A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two circular openings and one opening which is an elongated longitudinally oriented slot.
FIG. 6B is a perspective view of the distal tubular portion shown in FIG. 6A that has been rotated 180° from the view of FIG. 6A .
FIG. 7A is a perspective view of distal tubular portion of a tissue cutting member embodying features of the invention including two rectangular openings and one opening which is an elongated longitudinally oriented slot.
FIG. 7B is a perspective view of the distal tubular portion shown in FIG. 7A that has been rotated 180° from the view of FIG. 7A .
FIG. 8A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two rectangular openings and one opening which is an elongated longitudinally oriented slot.
FIG. 8B is a perspective view of the distal tubular portion shown in FIG. 8A that has been rotated 180° from the view of FIG. 8A .
FIG. 9A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two openings which are elongated longitudinally oriented slots.
FIG. 9B is a perspective view of the distal tubular portion shown in FIG. 9A that has been rotated 180° from the view of FIG. 9A .
FIG. 10A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two openings which are elongated longitudinally oriented slots with an enlarged circular shape at the proximal end thereof.
FIG. 10B is a perspective view of the distal tubular portion shown in FIG. 10A that has been rotated 180° from the view of FIG. 10A .
FIG. 11A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two openings which are elongated longitudinally oriented slots each having an enlarged circular shape between the proximal and distal ends thereof.
FIG. 11B is a perspective view of the distal tubular portion shown in FIG. 11A that has been rotated 180° from the view of FIG. 11A .
FIG. 12A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two openings which are elongated longitudinally oriented slots.
FIG. 12B is a perspective view of the distal tubular portion shown in FIG. 12A that has been rotated 180° from the view of FIG. 12A .
FIG. 13A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two openings which are elongated longitudinally oriented slots each having an enlarged circular shape at the proximal end thereof.
FIG. 13B is a perspective view of the distal tubular portion shown in FIG. 13A that has been rotated 180° from the view of FIG. 13A .
FIG. 14A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including two openings which are elongated longitudinally oriented slots with an enlarged circular shape at the proximal end thereof.
FIG. 14B is a perspective view of the distal tubular portion shown in FIG. 14A that has been rotated 180° from the view of FIG. 14A .
FIG. 15A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including four openings which are elongated longitudinally oriented slots.
FIG. 15B is a perspective view of the distal tubular portion shown in FIG. 15A that has been rotated 180° from the view of FIG. 15A .
FIG. 16A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including four openings which are elongated longitudinally oriented slots each having an enlarged circular shape at the proximal end thereof.
FIG. 16B is a perspective view of the distal tubular portion shown in FIG. 16A that has been rotated 180° from the view of FIG. 16A .
FIG. 17A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including four openings which are elongated longitudinally oriented slots.
FIG. 17B is a perspective view of the distal tubular portion shown in FIG. 17A that has been rotated 180° from the view of FIG. 17A .
FIG. 18A is a perspective view of a distal tubular portion of a tissue cutting member embodying features of the invention including four openings which are elongated longitudinally oriented slots each having an enlarged essentially circular shape at the proximal end thereof.
FIG. 18B is a perspective view of the distal tubular portion shown in FIG. 18A that has been rotated 180° from the view of FIG. 18A .
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a probe component 10 including a housing 12 and an outer tubular member or cannula 14 . The tissue cutting member 16 embodying features of the invention is slidably disposed within an inner lumen 18 in the cannula 14 . The probe component 10 may be part of a biopsy device such as that described in co-pending application Ser. No. 11/014,413 filed on Dec. 16, 2004. Details of the probe component 10 and other parts of the biopsy device may be found in the aforesaid application.
The cannula 14 of the probe component 10 has a distal tip 20 and an open tissue receiving aperture 22 spaced proximal to the distal tip 20 . The tissue receiving aperture 22 has an inner tissue cutting edge 24 . The tissue cutting member 16 is slidably disposed within the inner lumen 18 of the cannula 14 of the probe component, as shown in FIG. 2 .
The distal tip 20 of the cannula 14 may have a variety of tip shapes. The shape of the tissue penetrating distal tip disclosed in the above referenced co-pending application Ser. No. 11/014,413 has been found to be suitable for penetrating tissue, particularly breast tissue. Alternatively, the distal tip 20 may have an arcuate RF electrode such as disclosed in U.S. Pat. Nos. 6,261,241 and 6,471,700, (all of which have been assigned to the present assignee) that facilitate advancement of the probe through tissue.
FIGS. 3A-18B show tissue cutting member 16 having features of the invention including a distal tubular portion 26 . Preferably the tubular distal portion has a diameter of between about 0.1 inches and 0.2 inches. The distal tubular portion 26 has a distal tip 28 with an outer tissue cutting edge 30 and an inner tissue receiving aperture 32 and a longitudinal axis 34 . The distal tubular portion 26 also includes a longitudinally oriented opening 36 that has an open distal end 38 which opens to the inner tissue receiving aperture 32 and which has a closed proximal end 40 . Preferably the longitudinally oriented opening 36 has a length of about 0.1 inches to about 0.3 inches Additionally, a wall 42 of the tubular distal portion 26 has at least a second opening 44 (shown having a rectangular shape in FIGS. 3A-3F ) which is circumferentially spaced from the longitudinally oriented opening 36 about the longitudinal axis 34 .
Preferably the distal tip 28 of the distal tubular portion 26 has a beveled front face 46 with a leading edge 48 and a trailing edge 50 . The longitudinally oriented opening 36 in distal tubular portion 26 opens to the trailing edge 50 of the beveled front face 46 .
The distal tubular portion 26 preferably includes a flared distal section 52 which has a proximal end 54 and a distal end 56 and a cylindrically shaped proximal section 58 which has a proximal end 60 and a distal end 62 . The distal tubular portion 26 may have a junction 64 where the proximal end 54 of the flared distal section 52 meets the distal end 62 of the cylindrically shaped proximal section 58 . Preferably the flared distal section flares outward about 1° to 3° degrees from the cylindrically shaped proximal section. The open distal end 38 of the longitudinally oriented opening 36 facilitates the flaring of the flared distal section 52 as shown by line 66 . The flared distal section 52 ensures that the outer tissue cutting edge 30 of the distal tubular portion 26 engages the inner tissue cutting edge 24 of the tissue receiving aperture 22 , as shown in FIG. 2 , to provide scissor-like cutting motion for separating a tissue specimen from supporting tissue at the target biopsy site.
The longitudinally oriented opening 36 preferably has an enlarged essentially circular shape 68 at the closed proximal end 40 of the longitudinally oriented opening 36 . The closed proximal end 40 of the longitudinally oriented opening 36 can be located entirely within the flared distal section 52 (not shown), entirely within in the cylindrically shaped proximal section 58 as shown in FIGS. 9A-14B and 17 A- 18 B, or at least partially in the distal end 62 of the cylindrically shaped proximal section 58 as shown in FIGS. 3A-8B and 15 A- 16 B.
The second opening 44 (shown with a rectangular shape in FIGS. 3A-3F ) in the wall 42 of the tubular distal portion 26 allows for a vacuum to be maintained within the probe component 10 . Preferably the distal tubular portion 26 has a plurality of openings. The openings of the distal tubular portion are circumferentially disposed at an angle about the longitudinal axis 34 and the centers of these openings are preferably circumferentially located at about 90°, 135°, or 180° from a midpoint of the longitudinally oriented opening 36 . Preferably a third opening 70 (shown with a rectangular shape in FIGS. 3A-3F ) is provided in the wall 42 of the distal tubular portion 26 circumferentially spaced from the longitudinally oriented opening 36 and essentially opposite of the second opening 44 . The second opening 44 may have a variety of shapes for example, a rectangular shape, a circular shape, or an elongated shape such as an oval or elongated slot. Preferably when the second opening 44 is an elongated slot, the opening has a length of between about 0.1 inches and 0.4 inches. The second opening 44 and the third opening 70 preferably have the same shape, however, one or more of the openings may be of one shape and one or more of the other openings may be of another shape.
In one embodiment of the device having features of the invention, shown in FIGS. 3A-3E , the second and third openings 44 and 70 of the distal tubular portion 26 are circumferential rectangular openings. In this embodiment the longitudinal midlines of the second opening 44 and the third opening 70 lie in a plane perpendicular to the longitudinal axis 34 and are located in the flared distal section 52 of the distal tubular portion 26 . The closed proximal end 40 of the longitudinally oriented opening 36 is at the proximal end 54 of the flared distal section 52 .
FIGS. 4A and 4B show a cutting member 16 which embodies features of the invention wherein the second opening 44 a and third opening 70 a of the distal tubular portion 26 are circular openings and are located in the flared distal section 52 . The closed proximal end 40 of the longitudinally oriented opening 36 is located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 .
FIGS. 5A and 5B show a distal tubular portion 26 of the tissue cutting member 16 wherein the second opening 44 b and third opening 70 b are circular openings located at least partially in the distal end 62 of the cylindrically shaped proximal portion 58 . The closed proximal end 40 of the longitudinally oriented opening 36 is located at the proximal end 54 of the flared distal section 52 .
The distal tubular portion 26 in FIGS. 5A and 5B also includes a fourth opening 72 which is an elongated longitudinally oriented slot with a closed proximal end 74 and a closed distal end 76 . The fourth opening 72 is opposite to the longitudinally oriented opening 36 . The closed proximal end 74 of the opening 72 is located at the proximal end 54 of the flared distal section 52 . The closed distal end 76 of the fourth opening 72 is located in the flared distal section 52 .
FIGS. 6A and 6B show a tissue cutting member 10 wherein the distal tubular portion 26 has a second opening 44 c and a third opening 70 c which are located at least partially in the distal end 62 of the cylindrically shaped section 58 . FIGS. 6A and 6B also include a fourth opening 72 a which is an elongated longitudinally oriented slot with a closed proximal end 74 a and a closed distal end 76 a . The closed proximal end 74 a of the fourth opening 72 a is in the cylindrically shaped proximal section 58 and the closed distal end 76 a of the fourth opening 72 a is in the flared distal section 52 .
In the embodiment of the device having features of the invention shown in FIGS. 7A and 7B , the second opening 44 d and the third opening 70 d of the distal tubular portion 26 have a rectangular shape and are oriented perpendicular to the longitudinal axis 34 . The closed proximal end 40 of the longitudinally oriented opening 36 and the second 44 d and third 70 d openings are located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 .
FIGS. 7A and 7B also include fourth opening 72 b which is an elongated longitudinally oriented slot with a closed proximal end 74 b and a closed distal end 76 b . The closed proximal end 74 b of the fourth opening 72 b is located at the proximal end 54 of the flared distal section 52 . The closed distal end 76 b of the fourth opening 72 b is located in the flared distal section 52 .
FIGS. 8A and 8B show a distal tubular portion 26 of the tissue cutting member 16 which has a second opening 44 e and a third opening 70 e which have a rectangular shape and are oriented perpendicular to the longitudinal axis 34 . The second 44 e and third 70 e openings are located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 . FIGS. 8A and 8B also include a fourth opening 72 c which is an elongated longitudinally oriented slot with a closed proximal end 74 c and a closed distal end 76 c . The closed proximal end 74 c of the fourth opening 72 c is located in the cylindrically shaped proximal section 58 and the closed distal end 76 c of the fourth opening 72 c is located in the flared distal section 52 . In this embodiment the closed proximal end 40 of the longitudinally oriented opening 36 is located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 .
In the embodiment of the device having features of the invention shown in FIGS. 9A and 9B , the second opening 44 f of the tubular distal portion 26 is an elongated longitudinally oriented slot with a closed proximal end 78 and a closed distal end 80 . The closed proximal end 78 is located in the cylindrically shaped proximal section 58 . The closed distal end 80 of the second opening 44 f is located in the flared distal section 52 . The third opening 70 f is has the same shape as the second opening 44 f and the same orientation with respect to the flared distal section 52 and the cylindrically shaped proximal section 58 . In this embodiment the closed proximal end 40 of the longitudinally oriented opening 36 is located in the cylindrically shaped proximal section 58 .
FIGS. 10A and 10B show a distal tubular portion 26 of the tissue cutting member wherein the closed proximal end 40 of the longitudinally oriented opening 36 is in the cylindrically shaped proximal section 54 of the distal tubular portion 26 . The distal tubular portion 26 has a second opening 44 g which is an elongated longitudinally oriented slot with a closed distal end 80 a and a closed proximal end 78 a and an enlarged essentially circular shape 82 at the proximal end 78 a thereof. The closed proximal end 78 a of the second 44 g opening is located in the cylindrically shaped proximal section 58 and the closed distal end 80 a of second opening is located in the flared distal section 52 . The third opening 70 g of the distal tubular portion 26 has the same shape as the second opening 44 g and has the same orientation.
FIGS. 11A and 11B show a distal tubular portion 26 of the tissue cutting member 16 wherein the distal tubular portion 26 has a second opening 44 h which is an elongated longitudinally oriented slot with a closed proximal end 78 b and a closed distal end 80 b . The second opening also had an enlarged essentially circular shape 84 located between the proximal 78 b and distal 80 b ends. The closed proximal end 78 b of the elongated shape is in the cylindrically shaped proximal section 58 and the closed distal end 80 b of the elongated shape is in the distal flared section 52 . The enlarged essentially circular shape 84 of the second opening 44 h is at least partially in the distal end 62 of the cylindrically shaped proximal section 58 . The third opening 70 h is the same shape as the second opening 44 h and has the same orientation as the second opening 44 h . In this embodiment the closed proximal end 40 of the longitudinally oriented opening 36 is in the cylindrically shaped proximal section 58 of the distal tubular portion 26 .
FIGS. 12A and 12B show a distal tubular portion of the tissue cutting member 26 wherein the closed proximal end 40 of the longitudinally oriented opening 36 is in the cylindrically shaped proximal section 58 of the distal tubular portion 26 . The second opening 44 i is an elongated longitudinally oriented slot with a closed proximal end 78 c and a closed distal end 80 c . The closed proximal end 78 c of the first opening 44 i is located at the proximal end 54 of the flared distal section 52 . The closed distal end 80 c of the second opening 44 i is located in the flared distal section 52 . The third opening 70 i has the same shape and orientation as the second opening 44 i.
FIGS. 13A and 13B show a distal tubular portion 26 of the tissue cutting member 16 , which has a second opening 44 j which is an elongated longitudinally oriented slot with a closed distal 80 d end and closed proximal end 78 d . The closed proximal end 78 d has an enlarged essentially circular shape 86 . The closed distal end 80 d of the second opening 44 j is located in the flared distal section 52 and the closed proximal end 78 d is located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 . The third opening 70 j has the same shape and orientation as the second opening 44 j . In this embodiment the closed proximal end 40 of the longitudinally oriented opening 36 is in the cylindrically shaped proximal section 58 of the distal tubular portion 26 .
FIGS. 14A and 14B show a distal tubular portion 26 of the tissue cutting member 16 which has a second opening 44 k which is an elongated longitudinally oriented slot with a closed proximal end 78 e and a closed distal end 80 e . The closed proximal end 78 e of the elongated slot has an enlarged essentially circular shape 88 which extends toward the longitudinally oriented opening 36 . In this embodiment the closed proximal end 40 of the longitudinally oriented opening 36 is in the cylindrically shaped proximal section 58 of the distal tubular portion 26 .
FIGS. 15A and 15B show a distal tubular portion 26 of the tissue cutting member 16 wherein closed proximal end 40 of the longitudinally oriented opening 36 is located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 . In this embodiment the device has a second opening 44 l which is an elongated longitudinally oriented slot. The second opening 44 l a closed proximal end 78 f and a closed distal end 80 f . The closed distal end 80 f of the second opening 44 l is in the flared distal section 52 of the distal tubular portion 26 . The closed proximal end 78 f of the second opening 44 l is in the cylindrically shaped proximal section 58 . The third opening 70 l has the same shape and orientation as the second opening 44 l.
Additionally-the embodiment shown in FIGS. 15A and 15B includes a fourth opening 72 d a fifth opening 90 . The fourth opening 72 d is an elongated longitudinally oriented slot and has a closed proximal end 74 d and a closed distal end 76 d . The closed proximal end 74 d of the fourth opening 72 d is located at the proximal end 54 of the flared distal section 52 . The closed distal end 76 d of the fourth opening 72 d is located in the flared distal section 52 . The-fourth opening 72 d and the fifth opening 90 have lengths which are longer than the length of the second opening 44 l and the third opening 70 l.
FIGS. 16A and 16B show a distal tubular portion 26 of the tissue cutting member 16 which has a second opening 44 m , a third opening 70 m , a fourth opening 72 e , and a fifth opening 90 a . The second opening 44 m is an elongated longitudinally oriented slot with a closed proximal 78 g end and a closed distal end 80 g . The closed proximal end 78 g of the second opening 44 m has an enlarged essentially circular shape 92 which is located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 . The closed distal end 80 g of the second opening 44 m is located in the flared distal section 52 . The third opening 70 m has the same shape and orientation as the second opening 44 m . In this embodiment the closed proximal end 40 of the longitudinally oriented opening 36 is located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 .
The embodiment in FIGS. 16A and 16B also includes a fourth opening 72 e and a fifth opening 90 a . The fourth opening 72 e is an elongated longitudinally oriented slot with a closed proximal end 74 e and a closed distal end 76 e . The closed proximal end 74 e of the fourth opening 72 e has an enlarged essentially circular shape 94 which is located at least partially in the distal end 62 of the cylindrically shaped proximal section 58 . The closed distal end 76 e of the fourth opening 72 e is located in the flared distal section 52 . The fourth opening 72 e and the fifth opening 90 a have a length which is longer than the length of the second opening 44 m and the third opening 70 m.
FIGS. 17A and 17B show a tubular distal portion 26 of the tissue cutting member 16 wherein the closed proximal end 40 of the longitudinally oriented opening 36 is located in the cylindrically shaped proximal section 58 . This embodiment includes a second opening 44 n and a third opening 70 n . The second opening 44 n is an elongated longitudinally oriented slot with a closed proximal end 78 h and a closed distal end 80 h . The closed proximal end 78 h of the second opening 44 n is located in the cylindrically shaped proximal section 58 . The closed distal end 80 h of the second opening 44 n is located in the flared distal section 52 . The third opening 70 m has the same shape and orientation as the second opening 44 n.
The embodiment in FIGS. 17A and 17B also has a fourth opening 72 f and fifth opening 90 b . The fourth opening 72 f is an elongated longitudinally oriented slot with a closed proximal end 74 f and a closed distal end 76 f . The closed distal end 76 f of the fourth opening 72 f is located in the flared distal section 52 . The closed proximal end 76 f of the fourth opening 72 f is located at the junction 64 between the flared distal section 52 and the cylindrically shaped proximal section 58 . The fifth opening 90 b has the same shape and orientation as the fourth opening 72 f.
The embodiment of the device shown in FIGS. 18A and 18B has a second opening 44 o which is an elongated longitudinally oriented slot with a closed distal end 80 i and a closed proximal end 78 i . The closed proximal end 78 i of the second opening 44 o has an enlarged essentially circular shape located in the cylindrically shaped proximal section 58 . The closed distal end 80 i of the second opening 44 o is located in the flared distal section 52 . The third opening 70 o has the same shape and orientation as the second opening 44 o.
The embodiment in FIGS. 18A and 18B also include a fourth opening 72 g and a fifth opening 90 c . The fourth opening 72 g is an elongated longitudinally oriented slot with a closed proximal end 74 g and a closed distal end 76 g . The closed proximal end 74 g of the fourth opening 72 g is located at the proximal end 54 of the flared distal section 52 . The closed distal end 76 g of the fourth opening 72 g is located in the flared distal section 52 . The fifth opening 90 c has the same shape and orientation as the fourth opening 72 g . In this embodiment the closed proximal end 40 of the longitudinally oriented opening 36 is in the cylindrically shaped proximal section 54 of the distal tubular portion 26 .
The tissue cutting members shown in 17 A and 17 B and 18 A and 18 B may have an additional opening 96 shown in phantom in FIG. 18A .
The tubular portion 28 of the tissue cutting member 16 is preferably formed of surgical grade stainless steel. However, other high strength materials such as MP35N, other cobalt-chromium alloys, NiTi alloys, ceramics, glasses, and high strength polymeric materials or combinations thereof may be suitable. Further details of the tissue cutting member 16 may be found in the above mentioned application Ser. No. 11/014,413, filed on Dec. 16, 2004.
While particular forms of the invention have been illustrated and described herein, it will be apparent that various modifications and improvements can be made to the invention. For example, while the various embodiments of the invention have been described herein in terms of a biopsy device, it should be apparent that the devices and methods of utilizing the device may be employed to remove tissue for purposes other than for biopsy, i.e. for treatment or other diagnoses. Moreover, individual features of embodiments of the invention may be shown in some drawings and not in others, but those skilled in the art will recognize that individual features of one embodiment of the invention can be combined with any or all the features of another embodiment. Accordingly, it is not intended that the invention be limited to the specific embodiments illustrated. It is therefore intended that this invention to be defined by the scope of the appended claims as broadly as the prior art will permit.
Terms such a “element”, “member”, “device”, “section”, “component”, “portion”, “section”, “means”, “step” and words of similar import, when used herein shall not be construed as invoking the provisions of 35 U.S.C. §112(6) unless the following claims expressly use the terms “means” or “step” followed by a particular function without specific structure or action. All patents and patent applications referred to above are hereby incorporated by reference in their entirety.
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The invention is directed to tissue cutting members and biopsy devices with such tissue cutting member for separating a tissue specimen from a patient's body at a target site. The tissue cutting member is slidably disposed within an inner lumen of an elongated probe member of the biopsy device to cut a tissue specimen drawn into the interior of an outer cannula of the biopsy device through a tissue receiving aperture in the probe. The tissue cutting member has a tubular distal portion with a distal tip having an outer tissue cutting edge, an inner tissue receiving aperture, and a longitudinally oriented opening with a closed proximal end and open distal end which opens to the inner tissue receiving aperture to facilitate flaring of the distal tubular portion. The cutting member has at least one opening in a wall of the tubular portion to maintain a vacuum during use.
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This application is a division of application Ser. No. 09/130937, filed Aug. 7, 1998, pending.
BACKGROUND OF THE INVENTION
This invention is related to mechanical pumps for moving or pumping metal such as aluminum or zinc in a bath of molten metal, and more particularly to such a pump in which a motor supported above the bath drives a vertical stainless steel shaft. The lower end of the shaft drives the impeller to create a stream of molten metal. A ceramic sleeve shields the stainless steel shaft to protect it from the corrosive effects of the heated molten metal, as well as forming a loose fit with the shaft to accommodate differences in the thermal expansion characteristics between the ceramic and the stainless steel.
Mechanical power driven pumps for moving metal in a bath of molten metal conventionally have a relatively short life because of the destructive effects of the molten metal on the pump components. If the pump shaft connecting the motor to an impeller is formed of any steel to provide sufficient torque to move the impeller in the molten metal, the steel has a short life because it is chemically attacked by the molten metal. If the steel shaft is shielded by a protective coating of a ceramic material, then the different thermal expansion characteristics of the steel and the ceramic causes the ceramic to shatter in a relatively short time.
A shaft made of graphite alone will burn at the metal surface. A shaft made of ceramic alone does not have sufficient tensile, torque or impact strength to overcome the stresses normally encountered when pumping molten metal.
A pump housing submerged in molten metal and made of graphite or ceramic material to withstand the heat, tends to rise in the metal bath because the ceramic has a lower density than the metal. In order to prevent the pump housing from rising in the metal, it is desirable to mount a series of vertical legs between the pump housing and an overhead supporting structure. In addition the legs (or posts as they are also called) should be strong enough to overcome the tensile stresses created during installation and subsequent removal of the pump in the molten metal bath. Such legs experience problems similar to that of an unshielded pumping shaft, that is, if they are made of an uncoated steel they have a short life because the steel is attacked by the molten metal. If they are made entirely of graphite, the legs will bum at the metal interface. If a leg is made entirely of a ceramic material having good heat resistant characteristics, it has insufficient tensile strength to ensure a long life.
SUMMARY OF THE INVENTION
The broad purpose of the present invention is to provide a shielded stainless steel driving shaft for a centrifugal impeller-type pump immersed in a molten metal bath.
Another object of the invention is to provide an improved stainless steel leg (post) for supporting and preventing the pump housing from rising in the molten metal.
Still another object of the invention is to provide an improved static inlet filter configuration for an impeller pump immersed in a molten metal bath.
Still another object of the invention is to provide a ceramic shield surrounding a graphite leg and forming an inert gas chamber around the leg. An inert gas is delivered to the gas chamber to provide an oxygen-free environment around those graphite components of the leg that may tend to burn at the temperatures of the surface of the molten metal bath.
Still another object of the invention is to provide a dynamic filter for the inlet opening of the impeller of a pump mounted in a molten metal bath. The filter rotates with the impeller without interfering with the pumping vanes. Slinger ribs provided on the dynamic filter deflect debris attempting to enter the strainer apertures to prevent their passage into the pump housing.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.
DESCRIPTION OF THE DRAWINGS
The description refers to the accompanying drawings in which like reference characters refer to like parts throughout the several views and in which:
FIG. 1 is a longitudinal sectional view of an impeller pump immersed in a bath of molten metal and illustrating the preferred embodiment of the invention;
FIG. 2 is an enlarged view of the tongue carried on the lower end of the driving shaft for rotating the impeller;
FIG. 3 is a view as seen along lines 3 — 3 of FIG. 2;
FIG. 4 is a longitudinal sectional view of an impeller pump immersed in a bath of molten metal and illustrating a graphite quill shaft design with an external ceramic shield protection;
FIG. 5 is a view of an unshielded leg used for connecting a pump housing to an overhead structure;
FIG. 6 is a view illustrating a split ring employed for connecting the lower end of the leg to the pump housing;
FIG. 7 is an enlarged view as seen along lines 7 — 7 of FIG. 5;
FIG. 8 is a view of another arrangement for connecting the support leg to the pump housing;
FIG. 8A is a view of a graphite leg for supporting the pump housing, utilizing graphite cement for connecting the lower end of the leg to the pump housing;
FIG. 9 is a view as seen along lines 9 — 9 of FIG. 8A;
FIG. 10 is a view of a quill-shaft, ceramic support leg for the pump housing;
FIG. 11 is a view of another form of a quill-shaft, ceramic support leg for the pump housing;
FIG. 11A is a view of another form of a quill-shaft ceramic or graphite support leg for the pump housing;
FIG. 12 is an enlarged fragmentary view of a graphite inert quill-shaft support leg for the pump, having an oxygen-free chamber to eliminate oxidation of the graphite components;
FIG. 13 is a sectional view of a dynamic strainer for the pump;
FIG. 14 is a bottom view of FIG. 13; and
FIG. 15 is an enlarged view of the internal pumping vanes of the embodiment of FIG. 13 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, FIG. 1 illustrates a preferred impeller pump 10 having a lower pumping end disposed in a bath of molten metal 12 such as aluminum. The bath has a top metal level 14 . Typically the bath operates at a temperature not in excess of 1800° F. The bath is contained by a pot having a floor 16 . An electrically driven motor 80 is supported in any suitable location above the pump cover plate 18 , and is connected by a coupling 22 to a stainless steel pumping or driving shaft 24 . The shaft is supported in an opening 26 in the pump cover plate. The shaft has a sufficient length that the upper end is supported above cover plate 18 and its lower end is disposed in the bath of molten metal 12 .
A pump housing assembly 28 includes a housing 30 and a vane-type pumping member 32 disposed in the housing. The shaft is drivingly connected to the pumping member to rotate it in the housing in order to produce a stream of molten metal that enters the housing adjacent the floor of the pot through an inlet opening 34 , into a pumping chamber 36 and toward an outlet opening 38 in the direction of arrows 40 .
The pumping member includes a ceramic impeller 33 which carries pumping vanes 44 . Bearing means 46 carried in a shoulder 48 of the housing 30 engage a ceramic end driver 42 cemented to a vertical outer tubular ceramic shield 50 . The lower end of the end driver 42 is closed off and fits into pumping member 32 . The upper end of the shield extends upwardly through cover plate 18 . End driver 42 , after cementing, forms a single integral part of shaft assembly 20 together with shield 50 , tubular spacer shield 52 , steel driving shaft 24 and tongue 58 .
Inner ceramic tubular shield 52 is cemented to the inside of the outer shield 50 . The upper end of the inner shield is flush with the upper end of the outer shield. The inner tubular shield is shorter than the outer shield to form an annular shoulder 54 .
The lower end of the drive shaft 24 is threaded at 56 as illustrated in FIG. 1 . The threaded end 56 extends below shoulder 54 . A stainless steel tongue 58 is threadably mounted on threaded end 56 and seated on shoulder 54 in a manner that will be described.
Referring to FIG. 2, the inside bottom of the outer shield forms a chamber 60 . Tongue 58 is disposed in the chamber. Cement 62 is disposed in the chamber and has a socket 64 generally corresponding to the configuration of the tongue but slightly larger to provide for a clearance between the tongue and the socket to allow for thermal expansion differences.
As can be seen in FIG. 2, the bore 76 of the spacer shield 52 is larger than the diameter of the shaft 24 to provide a clearance which permits the shaft to expand in response to heat without creating an expansion tensile stress on the spacer shield 52 . Similarly, the tongue has a clearance that permits it to expand in response to heat without creating an expansion interference stress with the cement. The clearance between the driving structure (shaft) and the socket is formed by the steps of forming the outer tubular shield with a lower blind end, disposing a cement in the blind end of the outer tubular shield to form a socket having a configuration similar to but larger than that of the driving structure; disposing a wax that turns to a gas when exposed to the heat in a bath of molten metal, in the socket; disposing the driving structure in the wax; telescopically inserting the inner tubular shield and the outer tubular shield to engage the driving structure, and cementing the inner tubular shield to the outer tubular shield to form a unitary tubular shield around the shaft.
Referring to FIG. 1, coupling 22 forms the connection between the motor shaft and the shield assembly 20 that rotates pumping member 32 with impeller vanes 44 . torque from the shaft is transmitted through the tongue to the body of cement to outer tubular shield 50 to the end driver 42 , that is through the lower end of the shaft to the impeller. The shaft has a sufficient torque characteristic for driving the impeller in molten metal.
The inner spacer shield is located to form an annular air chamber 76 between the shaft and the inner shield along its full length. The air chamber has a size chosen to permit the stainless steel shaft to fully expand in the bath of molten metal without applying any expansion pressure on the ceramic shield. The shaft is then fully shielded by heat-resistant and molten metal resistant ceramic.
FIG. 4 illustrates a modified impeller pump 10 ′.
Bearing means 46 carried in a shoulder 48 of the housing 30 engage an inner graphite sleeve-like shield 50 ′. The lower end of shield 50 ′ is closed off and fits into pumping member 32 . The upper end of shield 50 ′ extends upwardly through cover plate 18 . Inner shield 50 ′ is cemented to a protective ceramic sleeve 78 ′ to form a single integral part of shaft assembly 20 together with, spacer shield 52 , steel driving shaft 24 and tongue 58 .
FIGS. 5-6 show various forms of an unshielded vertical leg that can be mounted between the pump housing 30 and cover plate 18 in order to lock the pump legs to the pump housing without the use of load-carrying cements, eliminating the need for large clearances between the legs and post sockets. Graphite cement is used only as a sealant to prevent molten metal penetration.
Graphite leg 120 has an upper end fastened to the cover plate by a threaded fastener 122 . The lower end of the leg is received in a cylindrical socket 124 in the pump housing. The leg's lower end has an annular enlargement 126 which is bottomed in the socket. The leg has an annular groove 128 above the enlargement for receiving a close fitting split ring 130 . The socket also has an annular groove 132 for receiving the split ring.
In this embodiment of the invention, the lower end of the leg is inserted into the socket by squeezing the split ring into groove 128 . Once the split ring is disposed in the socket, the shaft is pushed down until the split ring snaps into groove 132 thereby being disposed in both the groove in the leg and the groove in the socket, locking the leg in position.
FIG. 6 illustrates another embodiment of the invention in which a vertical leg 140 has an annular groove 142 for receiving a close fitting split ring 144 . The pump housing 30 has a socket 146 . The upper edge of the socket is chamfered as at 148 in such a manner that as the leg is inserted into the socket, the chamfered edge squeeze the split ring into the groove 142 . The leg is moved further into the socket until the split ring is partially expanded into the annular groove 150 in the socket. The split ring is disposed in both the socket of the leg and the groove of the socket thereby locking the leg to the housing.
In FIG. 8, housing 30 has a generally cylindrical socket with a radial groove 162 . The upper wall of the groove is adjacent a chamfered lip 164 . Split ring 166 is placed in groove 162 . When leg 168 is pushed into socket 160 , ring 166 will expand, then snap into groove 170 .
FIGS. 8A and 9 illustrate another version of a leg-housing locking device. Leg 171 has a groove 178 connected by means of passage 174 to an opening 180 located above the upper surface of housing 182 . Housing 182 has a socket 172 with an annular groove 176 . After leg 171 is inserted in housing socket 172 , graphite cement is injected under pressure in opening 180 and via passage 174 fills the cavity generated by grooves 176 and 178 in the housing and leg respectively, thus, preventing, after hardening, any axial displacement of the leg with respect to the housing.
FIG. 10 illustrates a shielded upright quill leg for supporting pump housing 30 beneath a cover plate 18 . An opening 181 is formed in housing 30 . An outer ceramic tubular shield 183 is formed with a length sufficient so that its lower blind end extends below the inside surface of the wall of housing 30 . The upper end abuts cover plate 18 .
An inner ceramic tubular shield 188 is disposed inside the outer shield and cemented along the length and around the inner shield in the area 190 (indicated by the heavier line). The lower end of the inner shield extends above the bottom of the outer shield. The upper end of the outer shield is located by an annular mounting member 192 that is attached to the cover plate. The lower end of the outer shield is threaded at 194 to receive a locking nut 196 which is screwed up to abut the inside surface of the housing.
A stainless steel leg 198 is disposed in the inner shield. The lower end of the stainless steel leg has a radial enlargement 200 which has a diameter less than the inner diameter of the outer shield but greater than the inner diameter of the inner shield so that it abuts the lower edge of the inner shield. Leg 198 is located so as to form an annular chamber 201 between the leg and the inner shield to permit the leg to thermally expand when it is disposed in the molten metal bath, without imposing an expansion stress on the shields.
The upper end of the leg is threaded at 202 for receiving a locking nut 204 and bevel washer 206 in order to lock the leg in position when it has been properly located within the ceramic shield.
FIG. 11 illustrates a slightly modified version of the shielded leg of FIG. 10 . In this case a tubular shield 210 comprises inner and outer ceramic shields similar to those illustrated in FIG. 10, and an internal stainless steel leg. The lower end of the outer shield has an enlargement 212 sequestered inside a corresponding similar enlargement in the housing instead of using nut 196 with the threaded configuration.
FIG. 11A illustrates a quill leg that is identical to that of FIG. 11 except that it has been cemented to pump housing 30 in accordance with common post-cementing procedures known by a person skilled in the art.
FIG. 12 illustrates another version of a shielded leg 220 for supporting pump housing 30 beneath cover plate 18 . This particular design utilizes graphite components in combination with a ceramic outer sleeve to protect the graphite outer shield. Although the graphite components of the leg are protected by the heat resistant ceramic shield, in some cases the air chamber between them or air leakage provides sufficient oxygen to allow the support leg components to bum.
In this case, a stainless steel leg 222 has an enlargement 224 carried at its lower end mounted within an inner graphite tubular shield 226 . The enlargement is seated against the lower end of the inner shield. The upper end of the leg is threaded at 228 to engage a fastening nut 230 and bevel washers 232 in such a manner that by tightening on nut 230 , enlargement 224 firmly seats graphite shield 226 in position against the bottom of the cover plate to form a gas chamber 234 around leg 222 .
An intermediate tubular graphite shield 236 telescopically receives the inner shield and has its internal surface cemented to the inner shield.
Leg 222 has a longitudinal gas passage 242 that extends from its upper end down to its lower end and also radially out through an opening 244 into chamber 234 .
The inner shield, in turn, has a small passage 246 which communicates with a passage 248 in shield 236 .
An outer ceramic tubular shield 250 encloses both of the graphite shields and has an internal annular chamber 252 in communication with passage 248 . Chamber 252 is filled with molten metal resistant cement. A source of nitrogen 254 is connected to passage 242 to form an oxygen-free atmosphere around the leg as well as an oxygen-free atmosphere along and around the graphite shields exposed to the metal level to prevent the graphite shields from burning.
FIGS. 13-15 illustrate a combination dynamic filter and pumping vane member 300 that may be substituted for the pumping member 32 illustrated in FIG. 1 . Pumping vane member 300 has an opening 302 for receiving the lower threaded end of pumping shaft 42 . A nut 303 attaches the body to the pumping member 300 . Pumping member 300 thus rotates with driving shaft 24 .
The pumping member has an internal chamber 304 with outlet opening means 306 and an apertured bottom strainer plate 308 . The strainer plate has an annular outer series of openings 310 and an inner series of openings 312 . The inner series of openings are in a bottom horizontal portion of the strainer plate while the outer inlet openings are in a frusto-conical wall.
Referring to FIG. 15, the pumping member has a series of pumping vanes 314 which are curved to form openings each having a width A in such a manner that as the pumping member is rotated, the pumping vanes draw the liquid metal through the inlet openings and then push the liquid metal out through the outlet opening means 306 . Strainer openings 310 and 312 have a maximum diameter B that is smaller than the larger openings A between the vanes. Thus the strainer openings prevent debris having a size larger than strainer openings B from entering into the pumping chamber thereby preventing any clogging of the vane openings.
A series of inner linear radial slinger bars 320 and outer radial slinger bars 322 are mounted on the strainer plate between adjacent strainer openings to strike any relatively large debris attempting to enter the strainer openings before they reach the vane openings. The slinger vanes strike the debris thereby permitting the pump to be located closely adjacent the bottom of the molten metal pot thereby permitting a stream of inlet liquid metal to be generated at a lower level in the pot.
Thus, it is to be understood that several variations have been described of an improved impeller-type pump useful in molten metal baths as well as several variations of shielded legs for supporting the pump in the molten metal bath.
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Apparatus for moving a stream of molten metal in a bath of molten metal, includes a pump disposed in the met. The pump has a lower inlet opening with a strainer and a slinger rib to prevent the entry of debris that exceeds a predetermined diameter from passing through the pump.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of PCT application serial number PCT/EP2010/001302 entitled “Lubricant for Powder Metallurgy” filed on Mar. 3, 2010 which claims priority to German patent application number 10 2009 013 021.7 filed on Mar. 16, 2009. The contents of both of these applications are incorporated by reference as if set forth in their entirety herein.
BACKGROUND
[0002] This disclosure relates to a lubricant for powder metallurgy as well as to its use and a sinterable powder mixture that includes the lubricant.
[0003] Lubricants for powder metallurgy are widely used in the manufacture of sintered parts. These sintered parts are often used in the automotive industry and, frequently, as components in engine and transmission systems. Among other things, one difficulty in the manufacture of sintered parts is obtaining a sintered part with a high density. Typically, a preform is first compacted from a sinterable powder in one or more steps to form a green body. This green preform is then sintered in a protective atmosphere during a second sintering step and may be subsequently sized or “coined” to create a strong and dimensionally accurate sintered part.
[0004] The density of sintered parts produced in this way largely depends upon the green density of the preform (also referred to as pressed density) that is achieved during the first compaction step. It is therefore generally desirable to have green bodies with relatively high densities after the compaction. In addition, the final density of a sintered part may be further increased by sizing or coining operations. Furthermore, sizing or coining may be used to improve the geometrical accuracy of the component as needed.
[0005] The high compression pressures commonly used in the state of the art for the manufacture of high-density green bodies result in a high degree of stress on the compaction punches and, moreover, lead to increased friction between the green preform and the die during ejection of the preform from the tool die after compaction. As a result, higher ejection forces must be applied to eject the preform which pose the risk of an undesired local re-densification and the formation of cracks in the green body. It is therefore generally known in the art that a lubricant may be applied to the surface of the punch and/or a suitable lubricant may be added directly to the powder mixture as a binder and to reduce the force for ejection.
[0006] A pressing additive for a sinterable powder mixture is known from DE 102 44 486 A1. This pressing additive contains 20% to 60% by weight a polyglycol and 40% to 75% by weight a montan wax.
[0007] Moreover, lubricants have also be used in sizing operations in order to reduce the forces on the sizing tool, thereby reducing the wear of the sizing tool, and to increase the density of the part, especially in areas near the surface. Generally, mineral oil-based sizing lubricants are used.
[0008] There are significant disadvantages to the lubricants currently in use, especially in the case of those used in metal powder mixtures as pressing additives or sizing lubricants. Many lubricants and/or stearates have skin-irritating or allergenic properties because of the high content of mineral oil or other oil-like substances. In addition, some of the previously used agents can no longer be used as a result of more stringent legal requirements.
SUMMARY
[0009] A lubricant is disclosed that has lubricating qualities similar to known lubricants, but without the handling considerations and constraints of existing lubricants. This lubricant for powder metallurgy comprises a carnauba wax and at least one plant- or animal-based fat. A carnauba wax is a vegetable wax with a density usually in the range of 0.990 g/cc to 0.990 g/cc and a melting point in the range of approximately 83° C. to approximately 86° C. Carnauba wax is primarily obtained from the leaves of the Brazilian palm tree, Copernicia prunifera (carnauba wax palm). By way of example, carnauba wax contains approximately 85% esters of wax acids by weight, w-hydroxycarboxylic acids and/or cinnamic acids with wax alcohols and diols. Additionally, carnauba wax also contains approximately 3% to approximately 5% free wax acids by weight, especially carnauba and cerotinic acids and, in addition, alcohols and diols, hydrocarbons and minerals. Mixtures of different kinds of carnauba waxes may be used. The carnauba waxes may have an iodine value in a range of approximately 8.5 to approximately 10.5. The acid value of the carnauba waxes may be in the range of approximately 1 to approximately 4 and the saponification value may be in the range of approximately 70 to approximately 83.
[0010] The plant- or animal-based fats are triglycerides. The term fat as used herein is synonymous with the term oil, so that it is possible to speak comprehensively of the group comprising fats and oils. These fats and oils largely comprise mixed glycerol esters of higher fatty acids with an even number of carbon atoms, whereby animal fats may also contain fatty acids with an odd number of carbon atoms. The fat may be selected from a group that includes one or more vegetable fats, prepared separately or as a mixture. The fat contained in the lubricant according to the invention may contain at least 6% oleic acid by weight in some forms and at least approximately 10% oleic acid by weight in other forms. Preferably, the quantity of oleic acid is in the range of approximately 6% to approximately 65% by weight, based on the total amount of fat respectively. The fat contained in the lubricant according to the invention has an iodine value of at least 40, and more preferably of at least 80. In an further embodiment, the fat in the lubricant has a saponification value of at least approximately 150 mg KOH/g, and more preferably of at least approximately 200 mg KOH/g.
[0011] This lubricant for powder metallurgy is primarily produced for the manufacture of sintered parts. Sintered parts are to be understood as parts that are manufactured entirely of a sinterable material or partly of a sinterable material (as is the case for composite parts). In some forms, a first portion of such a composite part can be manufactured, for example, of a mixture containing aluminum or iron, and a second portion that is connected to the first portion may be made of another material, e.g., cast iron, sintered or solid or manufactured of solid cast aluminum. In other forms, the composite part may have a sintered layer on surface(s) of a base material. In some forms, the sintered parts can be sized or coined using the lubricant and/or heat treated.
[0012] The sintered parts are primarily manufactured from a mixture comprising at least one metallic material and/or plastic material and at least one lubricant for powder metallurgy. Sinterable materials are, as used herein, powders or powder mixtures made of metallic, ceramic and/or plastic components; for example, low alloy steels, chromium-nickel steels, bronze, nickel-based alloys such as Hastalloy, Inconel, metal oxides, metal nitrides, metal silicides or the like, and further, powders or mixtures containing aluminum, whereby the mixtures may also contain high-melting components such as platinum or the like. The powders and their particle sizes depend upon the particular application. By way of example, powders that contain iron are alloys such as 316L, 304L, Iconel 600, Iconel 625, Monel and Hastalloy B, X and C as well as 17-4PH. By way of example, low-alloy steel powders may include, for example, carbonized steel, Distaloy AB, AE, DE and HP (Högäns AB, Sweden) and Ancorsteel 4300 (Hoeganaes Corp., USA). Titanium and/or titanium alloys are also suitable materials, even when mixed with other materials, such as powders containing iron. Furthermore, the metallic material and/or plastic material may include synthetic fibers or fibers such as fibers with a diameter between 0.1 μm to approximately 2 μm and of a length of a few microns up to approximately 50 millimeters. In addition, carbon may be added in the appropriate quantity to some metallic materials (e.g., iron) in order to arrive at the desired alloys. Other additives such as binding agents or the like may also be added. In addition, the sinterable mixture may also contain at least one stabilizing agent and/or at least one anti-agglomeration agent. Furthermore, the sinterable mixture may also contain self-lubricating materials such as MoS 2 , WS 2 , BN and/or other carbon modifications such as coke, polarized graphite or the like in addition or as an alternative to graphite. In addition, the sinterable mixture may contain aerosols, as well as other additives known to the person skilled in the art, depending upon the particular application.
[0013] Some lubricants of the type described have the significant advantage that, with the lubricant, sinterable materials or material mixtures have a compressibility similar to that found when conventional pressing additives are used. Furthermore, some lubricants of the type described can be used as a sizing lubricant by which it is possible to achieve an especially high force for a unilateral calibration on the lower punch, for example, using load cells. Furthermore, the ejection pressures are as low as for lubricants known from the prior art that are, however, more disadvantageous from a handling/environmental perspective.
[0014] In one preferred embodiment, at least one of the fats comprised in the lubricant is solid or fluid.
[0015] Here, the aforementioned aggregate states are based on a temperature of 20° C., but, depending on the composition and viscosity, a fat that melts at 5° C., for example, may also be referred to as a solid fat. In some embodiments, at least one fat may be a triglyceride, which is a glycerol ester with predominantly saturated fatty acids, meaning that the glycerol ester is comprised of at least two fatty acids.
[0016] In one preferred embodiment, the lubricant includes at least one fat that is a solid at a temperature of 20° C. in addition to carnauba wax. In another preferred embodiment, the lubricant according to the invention includes at least one fat that is a solid at a temperature of 20° C. and at least one fat that is liquid at 20° C., in addition to carnauba wax.
[0017] At least one fat in the lubricant for powder metallurgy may be selected from a group that includes rapeseed oil, coconut oil, soya oil, linseed oil, palm oil and/or fat, sunflower oil, walnut oil, hazelnut oil, olive oil, castor oil, tallow and/or fish oil and derivatives of the aforementioned substances. Particularly suitable derivatives include hydrogenated or oxygenated compounds of the aforementioned substances. Mixtures of the specified substances may be used.
[0018] The lubricant may contain at least 50% carnauba wax by weight and at least 10% by weight of one of the vegetable fats that is a solid at a temperature of 20° C., where the weight percentages are calculated based on the total amount of the lubricant.
[0019] The lubricant may contain carnauba wax in an amount of 65% to 90% by weight and the at least one solid vegetable fat in an amount of 10% to 35% by weight, each calculated on the basis of the total weight of the lubricant. In some forms, the lubricant may contain no additional substances besides carnauba wax and the minimum of one solid vegetable fat.
[0020] The lubricant may contain at least approximately 5% carnauba wax by weight, at least approximately 20% by weight of a first vegetable fat that tends to be solid at a temperature of 20° C., and at least approximately 40% by weight of a second vegetable fat that is liquid at a temperature of 20° C., whereby the weight percentages are calculated based on the total quantity of the lubricant. In this embodiment, the lubricant may contain carnauba wax in an amount of approximately 6% to approximately 15% by weight, the first vegetable fat in an amount of approximately 30% to approximately 45% by weight and the second vegetable fat in an amount of approximately 45% to approximately 65% by weight. The lubricant may, in some forms, contain no further substances in addition to a second liquid vegetable fat, a first vegetable fat and carnauba wax. That embodiment of the lubricant is especially suitable for use as a sizing lubricant, as no drying step is required before sizing, as is often the case for sizing lubricants that contain solvents as is found in prior art. The lubricant as further described above, which contains a higher proportion of carnauba wax, is preferably used as a pressing additive and is more preferably mixed directly into a powder mixture.
[0021] Insofar as ranges or number ranges are indicated, it should be noted that the particular upper and lower values of these ranges are not absolute values. Rather, some deviations from the numerically defined as upper and lower limits may be made where the application so demands. Here, variances within a deviation range of up to 5% from the indicated numeric value of the upper and/or lower level are possible.
[0022] The present invention also pertains to the use of a lubricant as defined above, as an additive to a sinterable powder mixture, or in other words, as a pressing additive or, in some alternate forms, as a sizing lubricant in powder metallurgy.
[0023] Finally, the present invention also pertains to a mixture for the manufacture of sintered parts comprising at least one metallic material and/or plastic material and at least one lubricant for powder metallurgy as defined above. A sinterable powder mixture will be used that further contains at least one plastic and/or metallic powder material in addition to at least one disclosed lubricant. The mixture for the manufacture of sintered moldings according to the invention primarily contains 0.1% to 2% of the lubricant by weight, calculated on the basis of the total weight of the mixture. In addition, aside from the aforementioned metallic and/or plastic materials, including by way of mixtures, the sinterable powder mixture may also contain further additives, such as aerosols, graphite, self-lubricating materials, binding agents, and so forth.
[0024] These and still other advantages of the invention will be apparent from the detailed description and drawings. What follows is merely a description of some preferred embodiments of the present invention. To assess the full scope of the invention the claims should be looked to as these preferred embodiments are not intended to be the only embodiments within the scope of the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a chart depicting the green density of compacted parts using convention Licowax C lubricant and one formulation of the disclosed lubricant at various compaction pressures.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Pressing Additive
[0026] A lubricant that is used as a pressing additive is provided by a mixture of 16.7% coconut oil by weight and 83.3% carnauba wax by weight. The coconut oil was still a solid fat at a temperature of 20° C. with a saponification value of 255 mg KOH/g to 260 mg KOH/g. The coconut oil was purchased under the trade name Palmin, which is manufactured by the company Peter Kölln KGaA, Elmshorn, Germany. The carnauba wax that was used was obtained under the type designation 7170, manufactured by the company Willy Benecke GmbH, Hamburg, has a melting range of 78° C. to 90° C. and an acid value or 2 to 10 as well as an ester value of 70 to 82. The carnauba wax was available in powder form.
[0027] The coconut oil, which was available in block form, and the carnauba wax, which was available in powder form, can be melted together in the indicated amounts for the manufacture of the lubricant. However, in other forms of production, they can also be mechanically mixed together as solids (after reconstituting the coconut oil into a powder or pellet form). If the lubricant is manufactured by melting together the components, the melt may be allowed to cool and then may be ground or atomized. The lubricant that was produced in this way and that is usable as a pressing additive was obtained as a solid powder at a temperature of 20° C.
[0028] The prepared lubricant was added to a sinterable metallic powder as a pressing additive. The base powder was a water-atomized iron powder available under the trade name 1000 BMn, manufactured by Hoeganaes Corporation, Cinnaminson, USA. To this base powder was added 2% copper by weight in powder form and 0.6% graphite by weight available under the trade name UF-4, manufactured by Graphit Kropfmühl AG, Hauzenberg, Germany. The pressing additive was added to this powder mixture in an amount of 0.6% by weight of the lubricant and the mixture was homogenously mixed. The sinterable powder mixture thus prepared was placed in a conventional compaction press and uni-axially pressed into bushings with an outside diameter of 14.3 mm, an inside diameter of 9 mm, and a height of 13.3 mm at different pressures and a mold temperature of 25° C. as well as an M/Q ratio of 10 (lateral surface to cross section ratio).
[0029] For comparison, a sinterable powder mixture of the aforementioned metal composition was prepared, whereby instead of 0.6% by weight of the stated lubricant being added as a pressing additive, this later preparation used an amount of 0.6% by weight of the pressing additive known from the prior art, Licowax C manufactured by Clariant GmbH, Frankfurt am Main, Germany, which is a bisstearoylethylenediamine (amide wax).
[0030] The density of the produced green bodies was measured at different pressing pressures, both for the powder mixture and for the comparison mixture in accordance with DIN 1503369 (impermeable sintered metals and carbides/investigation of the density). The density was obtained at pressing pressures of 400 MPa, 500 MPa and 600 MPa.
[0031] FIG. 1 shows that when the newly disclosed lubricant was used as a pressing agent, the densities of the produced bushing-shaped green bodies were higher than those achieved when the lubricant known and tested from the prior art, Licowax C, was used. Unlike Licowax C, however, the newly disclosed lubricant is environmentally friendly and cost-effective.
Sizing Lubricant
[0032] Another lubricant, this time for sizing, was prepared using 54% rapeseed oil by weight (second vegetable and liquid fat), 36% by weight of a first vegetable fat and 10% carnauba wax by weight. The carnauba wax used here corresponded to that which is used in the lubricant as a pressing additive, described above in greater detail. The rapeseed oil had a melting point of −5° C. and, therefore, can be considered a liquid fat in the sense of the present application. The saponification value was 375 mg KOH/g, the iodine value 107, the viscosity, measured at 35° C. and measured dynamically, was 39 mPa/s (measured in accordance with DIN 53015). The used first vegetable fat had a melting point of +3° C. and a viscosity, measured at 35° C. and measured dynamically, of 78 mPa/s (measured in accordance with DIN 53015) and, therefore, can be considered to be a solid fat. The first fat had a saponification value of 380 mg KOH/g and an iodine value of 92 mg KOH/g. The proportion of oleic acid in the first fat was approximately 52% by weight, whereas the oleic acid in the rapeseed oil that was used was present in an amount of approximately 59% by weight. The individual components of the lubricant (which can be used as a sizing lubricant) were mixed at an increased temperature of approximately 80° C. in liquid form.
[0033] Using the prepare sizing lubricant, bushings were produced out of a water-atomized iron having an inner diameter of 9 mm, an outside diameter of 14.3 mm, and a height of 25 mm. The water-atomized iron was manufactured under the trade name of ASC100.29 manufactured by Hoeganaes AB, Sweden. The aforementioned iron powder was pressed, together with 0.6% Licowax C by weight, into the aforementioned components. The lateral surface to cross section ratio was 19. The green parts obtained were sintered at 1120° C. for approximately 20 minutes in a continuous belt oven. Once the manufacturing step of sintering and cooling to room temperature is complete, the bushings obtained in this manner were dipped in the calibration lubricant at 20° C.
[0034] After the dipping process and, if necessary, drying step (a processing step which, unlike lubricants known from prior art, is not necessary using the above-described sizing lubricant), the bushings coated with the lubricant were placed in an appropriate sizing tool and a unilateral sizing was performed using an upper punch with a force of 800 MPa. In so doing, the forces that resulted from the upper punch during sizing were measured using load cells manufactured by Hottinger Baldwin, Darmstadt, Germany. The forces on the lower punch were measured first. After sizing, the samples were then ejected from the lower punch of the sizing tool and the force needed to do so was measured. While the forces measured on the lower punch should be as high as possible during sizing, the forces measured when the component is ejected from the tool should be as low as possible.
[0035] The lubricant mixture prepared as described above, which can be used as a sizing lubricant, was compared with the conventional lubricant, Multical EJ10 manufactured by Zeller+Gmelin GmbH & Co. KG, Eislingen/Fils, Germany (which in the meantime has been removed from the market), and which is a solvent-containing wax. It was also compared with Rustilo DWX 30 manufactured by Castrol Industrie GmbH, Mönchengladbach, Germany, which is used as a calibration lubricant, and which is a solvent-containing fat.
[0036] The following table, Table 1, compares the measured forces and the manufacturing conditions.
[0000]
TABLE 1
Drying
Drying
Tool
time
at
Temp.
P Lower punch
P US-off
Manufacturer
Basis
Product
[min]
(° C.)
(° C.)
[MPa]
[MPa]
Zeller + Gmelin
Wax,
720
25
25
579
165
GmbH &
containing
Co. KG
solvent
Castrol
Fat,
Rustilo
300
25
25
215
515
Industrie
containing
DWX 30
GmbH
solvent
Disclosed
Carnauba
Disclosed
0
25
25
490
185
lubricant
wax,
lubricant
rapeseed
oil, semi-
solid
plant fat,
solvent-
free
[0037] As can clearly be seen in the table above, the newly disclosed lubricant, used as a sizing lubricant, shows improved qualities both in terms of the forces measured at the lower punch as well as relative to the measured ejection pressure values, which fall between those of sizing lubricants known from the prior art, and specifically in ranges that are relevant to practical application. Moreover, the newly disclosed sizing lubricant demonstrates extraordinarily environmental friendliness and occupational safety qualities in comparison to the conventional sizing lubricants.
[0038] It should be appreciated that various other modifications and variations to the preferred embodiments can be made within the spirit and scope of the invention. Therefore, the invention should not be limited to the described embodiments. To ascertain the full scope of the invention, the following claims should be referenced.
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A lubricant for use in a powder mixture is disclosed. This lubricant contains carnauba wax and at least one plant- or animal-based fat. A powder mixture using this lubricant can be used to compact green parts have higher densities and helps to improve the life of the tools compacting the powder.
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[0001] This application is a Divisional of co-pending application No. 11/935,994 filed on Nov. 6, 2007, the entire contents of which are hereby incorporated by reference and for which priority is claimed under 35 U.S.C. §120.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to printed wiring boards (PWBs) and, more particularly, to methods and apparatuses that enable coefficient of thermal expansion (CTE) matching and heat dissipation for integrated circuit (IC) components attached to PWBs.
[0004] 2. Description of Related Art
[0005] Currently, microelectronic modules and module sub-assemblies typically require that the heat-generating integrated circuit (IC) components of the module be mounted on thermal vias in the printed wiring board (PWB) or on external module housings to effectively remove heat from the module and allow it to operate properly and effectively.
[0006] While this approach of separating the heat-generating ICs from the other components of the module is a valid solution, the two approaches of thermal vias and module housings both have serious drawbacks. The use of a module housing to mount heat-generating components increases the cost and manufacturing time for the module. There is the expense of machining the module housing, and also of all the additional wiring and work required to connect the heat-generating components to the other parts of the module.
[0007] The use of thermal vias, while eliminating the need for a module housing and reducing the amount of additional wiring and work required to connect all the module components, introduce serious reliability problems because of the coefficient of thermal expansion (CTE) mismatch that occurs when heat-generating components are mounted on a layer of Copper or other ductile metal for effective heat dissipation. Because of the mismatch in CTE between the component and the metal layer, the reliability and usable life of the module is reduced.
[0008] Current technology does not have a ready solution for the combined problems of CTE matching and heat dissipation. While several attempts have been made to include layers in a PWB that will allow the board to have a tailorable CTE that can be matched to the components mounted on it, such as altering the chemistry of the dielectric materials or using specially formulated pregs, they consider the issue of the CTE of the whole board, and do not address the potentially disparate needs of individual board components. To this end, the CTE matching technologies available for PWB manufacture today reside mainly in the substrate and bonding layers of a PWB and do not address the ability to mount components to a metallization layer. Also, none of these approaches have dealt with the issue of heat dissipation. Even in a PWB that is CTE matched to the heat-generating components, there is still a need for a heat sink and a method for drawing the heat away from the components and into the sink.
[0009] This is especially problematic for radio-frequency (RF) applications. High-frequency components such as microwave circuits not only generate a great deal of heat, but also need to be mounted on a metal surface so that they have an RF ground. None of the available CTE matching solutions are viable for RF components because all of the CTE-matching materials currently used in PWBs are meant for bonding or dielectric layers, and cannot be put in direct contact with the RF components without a significant loss of performance. Further, several of the known methods for accomplishing CTE matching in a PWB entail altering the chemistry of the dielectric materials themselves, leading to further potential degradations in frequency performance.
SUMMARY OF THE INVENTION
[0010] Aspects of the present invention are directed at solving the problems of how to best remove heat from wiring boards and improve reliability in a cost-effective and time-efficient fashion. Aspects of the invention pertain to production of PW Bs that contain a relatively thick layer of engineered material which provides coefficient of thermal expansion (CTE) matching for components mounted on the board, a mounting surface for heat-generating IC components and improved thermal dissipation capabilities that reduce the need for thermal vias, expensive component housings and the attendant issues of connecting the components. Aspects of the present invention are directed at solving the problems of accomplishing CTE matching without degrading frequency performance of RF components.
[0011] Recently, advances in metallurgy and materials engineering have led to the creation of metals and metallic materials that can be tailored to have specific CTEs and thermal properties. It has been discovered that the inclusion of a thick layer of such an engineered material as the layer 2 metallization of a PWB will allow for the attachment of heat-generating components to this metallization layer. The combination of a tailorable CTE and good heat dissipation provides an elegant solution to the problems usually encountered in mounting heat-generating components to a PWB.
[0012] Unlike prior attempts at CTE matching, the inventive processes include the use of a thick layer of engineered material to enable the combination of mounting of heat-generating components, customizable CTE matching, and good thermal dissipation into one layer of a PWB. This is a novel use of an existing material to combine three previously disparate features into one cost-effective, easily produced solution.
[0013] In looking for a suitable material for the PWB layer that would allow for hot component surface mount and CTE match, it was determined that an increase in the thickness of such a CTE matched substrate would provide effective heat dissipation without the need for thermal vias or expensive metal housings.
[0014] The inclusion of an engineered metal into the PWB manufacturing process may entail minor changes to the manufacturing process but offers significant cost savings over the existing alternatives for CTE match and heat dissipation.
[0015] One difference in manufacturing is a result of the electrically conductive nature of the engineered material.
[0016] Before including the engineered material in the PWB stack, the areas where electrically isolated (non-ground) vias are intended must be identified. Electrically isolated vias may be necessary where connections between circuit pathways on different PWB layers are desired or where specific components on the PWB may need to be directly connected to elements not on the PWB.
[0017] Because of its thickness, the CTE-matching material is not etched like a typical Cu metallization layer, oversized holes may be drilled through the material at the points where the electrically isolated vias are intended. These holes may then be filled with a non-conductive epoxy so that when the electrical via holes are drilled and plated through on the assembled PWB, the plating will not come in contact with the CTE-matching layer.
[0018] If the engineered material selected for use is not electrically conductive, the steps of pre-drilling and epoxy filling are not necessary. A non-conductive material may be desirable in situations where an RF ground is not necessary or where all the components are SMDs. Preferred embodiments, however, accommodate RF components and using the engineered material as the ground plane for such RF components provides a distinct advantage.
[0019] Once the PWB is complete, embodiments of the invention may then call for LASER ablated cavities in the PWB to expose the CTE-matching layer so that heat-generating components can be mounted directly to the CTE-matching layer.
[0020] Advantages of the present invention include the ability to control both the in-plane CTE and the thermal dissipation properties of a PWB while using existing manufacturing and processing techniques and technologies to create this new type of PWB. Using a material capable of metal-like heat dissipation without a metal-like CTE allows for significant increases in the thickness of a PWB metal layer without the introduction of additional mechanical stresses. The fact that such a material is available in an electrically conductive embodiment provides the further advantage of acting as a ground plane for RF applications, meaning that RF components, which typically generate a great deal of heat, can be mounted to the CTE-matching layer of the PWB for a combined benefit of CTE matching, heat dissipation, and RF ground.
[0021] Further scope of applicability of the present invention will become 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 this detailed description.
BRIEF DESCRIPTION OF DRAWINGS
[0022] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein
[0023] FIG. 1 a. Is a cross-sectional diagram according to aspects of the invention showing the inventive PWB structure and a relative position of the CTE-matching layer;
[0024] FIG. 1 b Is a cross-sectional diagram of a PWB without a CTE-matching layer and with external heat sinks and thermal vias;
[0025] FIGS. 2 a - e are process diagrams illustrating a method of manufacturing a PWB according to the invention;
[0026] FIGS. 3 a - d are another set of process diagrams illustrating a method of manufacturing a PWB according to the invention; and
[0027] FIGS. 4 a - b compare a typical PWB to one manufactured according to an embodiment of the inventive process.
[0028] The drawings will be described in detail in the course of the detailed description of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims and equivalents thereof.
[0030] The scenario outlined in the description of the related art may be better appreciated with the understanding that both die-form and surface mount device (SMD) packages for heat-generating ICs may require an in-plane CTE as low as 7 to 10 ppm/C and a heat sink with thermal conductivity of 300 to 400 W/mK or better. The CTE of Copper is 17 ppm/C, meaning that attaching an RF component directly to copper will likely cause either the solder joint or the package or the chip itself to crack from the repeated mechanical stresses of constant expansion and contraction.
[0031] Although the thermal conductivity of Copper is ˜400 W/mK, this is not helpful because the typical thickness of metal layers in a PWB is ˜1 mil. Having a thicker layer of metal would improve heat dissipation, but it would also increase the mechanical stresses caused by the CTE mismatch that exists between the metal and the IC components as well as between the metal and non-metal layers of the PWB.
[0032] Recent advances in metallurgy and composite materials have resulted in the creation of engineered substances that have the electric and thermal properties of metals while exhibiting a CTE that can be tailored, based on their specific material composition, to be less than 10 ppm/C. The use of such materials in constructing new types of PWBs that are better suited to hold RF and other heat-generating components should be evaluated from a standpoint of using existing manufacturing technologies wherever possible, so that maximum advantage can be gained from the innovative use of the material while also providing cost savings over current module production practices.
[0033] The ability to combine in-plane CTE control and effective heat dissipation into a single layer of a printed wiring board (PWB) is made possible by the use of a relatively thick layer of engineered material as the layer 2 metallization of the PWB.
[0034] A primary aim of controlling the CTE of the layer 2 metallization is to provide a thermally dissipative surface for heat-generating IC components that is free from the usual mechanical stresses associated with the expansion and contraction of metal.
[0035] Because thermal conductivity is a function of thickness as well as surface area, it is important that the CTE-matching layer have a thickness sufficient to allow for heat dissipation without requiring the use of thermal vias or a module housing. The thickness of the CTE-matching layer is determined primarily by the heat dissipation requirements of the particular module being assembled and the thermal conductivity of the material used for the CTE-matching layer. This is further moderated by concerns for the overall thickness of the resultant PWB due to potential pre-existing size requirements, and the need to plate electrical via holes, which have a minimum height to diameter aspect ratio of 5:1.
[0036] One inventive embodiment uses a Copper-Graphite composite material as the CTE-matching layer for a RADAR transceiver module. In this embodiment, it was also desirable that the engineered material be metal so that in addition to CTE matching and heat dissipation, it provided an RF ground for microwave ICs mounted to its surface. Portions of the CTE-matching layer used for surface mounting may be exposed by LASER ablation of the uppermost dielectric material in this embodiment.
[0037] Other inventive embodiments may use different materials such as metallized ceramics depending on the specific CTE, thermal conductivity, and frequency performance desired. For applications that do not require frequency performance, the CTE-matching layer may not require any metal. The CTE-matching layers of these embodiments may also be exposed for surface applications by LASER ablation, or may use alternative techniques such as mechanical abrasion or etching.
[0038] The specific properties of interest of the Copper-Graphite material are its CTE of 7 ppm/C and thermal conductivity of 400 W/mK. Given the amount of heat generated from the components of an RF transceiver module, the appropriate thickness for the composite material was determined to be 40 mils, compared to the typical metallization layer in currently produced PWBs, which uses 1 oz. of Cu, for a thickness of ˜1 mil.
[0039] One property useful in embodiments of the inventive method is compatibility with copper or palladium plating and industry-standard PWB fabrication processes. The ability to introduce the CTE-matching material into existing and widely used manufacturing processes is essential to material and cost saving PWB embodiments of the type disclosed herein,
[0040] FIG. 1 a shows a cross-section of PWB created in the composite material embodiment of the inventive process. Heat-generating RF components 10 are attached to the PWB by means of eutectic solder in cavities 75 where the top substrate layer 55 of the PWB has been LASER ablated to expose the composite material comprising the layer 2 metallization 40 of the PWB. The RF components 10 are then connected to the top-layer metallization 80 . In this embodiment, that connection is accomplished by using conventional wire-bonds 15 such as Thermosonic Gold wire. Alternative means of attaching and connecting the heat-generating RF components may include conductive epoxy and wedge bonding, respectively. The manufacturing process resulting in the structure of FIG. 1 a is discussed below.
[0041] FIGS. 2 a - e discuss the PWB stack-up process whereby the composite material layer is added to this embodiment of the inventive process. Typically, PW Bs are constructed of material cores (foil/dielectric/foil) that are laminated together using pregs (a dielectric glue to hold the cores together to form a core stackup). The processes for creating and laminating material cores together are known to individuals with ordinary skill in the art of PWB manufacture. The top layer of a PWB created according to an embodiment of the inventive method would be a one-sided dielectric core (foil/dielectric) attached to the CTE-matching layer using a preg. An alternative embodiment may allow for simply covering the CTE-matching layer with a preg to prevent unwanted electrical contact with the CTE-matching layer. The techniques of using one-sided material cores and pregs in this fashion are also known to individuals with ordinary skill in the art of PWB manufacture.
[0042] FIG. 2 a begins with a PWB stack of Cu metallization 220 and an FR4 substrate. 225 . Alternative embodiments of the inventive method may use a substrate 225 comprised of various materials including ceramics, phenol based resin, Teflon, or fiberglass. Alternative embodiments of the inventive method may also use an exotic metal such as palladium instead of copper, but this would greatly increase the cost of production. This portion of the stack is fabricated in a first lamination cycle according to lamination techniques known to individuals with ordinary skill in the art of PWB manufacture.
[0043] The topmost layer of substrate 200 is a high-performance laminate chosen, in this embodiment of the inventive method, for its low loss high frequency dielectric properties. In other embodiments of the invention not meant for high frequency applications, an epoxy resin bonded glass fabric, such as the one known as FR-4, or any other possible lower-layer substrate could also be used as the topmost layer of substrate 200 . Further, different frequency requirements could also necessitate the use of high performance laminates in the lower substrate layers 225 of the PWB in alternative inventive embodiments.
[0044] After the first lamination cycle, the top core, the CTE-matching material, and a binding preg to attach the CTE-matching material to the rest of the PWB are laminated with the first lamination set to form a completed PWB.
[0045] FIG. 2 b Demonstrates the addition of the composite material. Once the lower lam set has been established/constructed, a preg layer, the predrilled and back filled CTE-matching material, and the top dielectric and foil (in foiled preg form) are added to the stack to form the final lamination set as depicted in FIG. 2 c.
[0046] FIG. 2 d shows a cross-section of the complete PWB stack created by this embodiment of the inventive process and demonstrates the creation of the ablated cavities 280 , which can be accomplished by a variety of methods including LASER ablation and mechanical cutting with a controlled depth router bit. These cavities expose the layer 2 metallization 240 for attachment of heat-generating parts 290 - 1 such as RF components 290 - 2 by means of epoxy attachment, soldering, or pressure-mountings depicted in FIG. 2 e.
[0047] Because this embodiment uses a metal as the layer 2 metallization, locations where electrically isolated vias are intended in the PWB must be identified before the CTE-matching layer can be inserted into the PWB stack.
[0048] The CTE-matching layer 40 , because it cannot readily or easily be etched due to its thickness, may have holes drilled into it where the electrically isolated vias 100 are intended. These holes should be larger in diameter than the size of the intended via holes. The holes may be created by a variety of methods including mechanical or LASER drilling, they are then back-filled with an electrically non-conductive epoxy 85 . Once the via holes are drilled through the PWB they are coated with electrically conductive material 90 by plating Copper along the inside the holes. The conductive material may also be introduced into the electrically isolated via hole by filling it with a conductive paste or other conductive material (such as solid silver) after the entire board stack is laminated. Because electrically isolated via 100 is drilled through the epoxy 85 , the conductive material 90 lining the via hole 100 will remain electrically isolated from the metal in the CTE-matching layer 40 .
[0049] FIGS. 3 a - d illustrate the drilling and epoxy-filling aspects of including a metal CTE-matching layer into a PWB where an electrically isolated via is intended. In this example, the CTE-matching material is assumed to be electrically conductive. Non-conductive embodiments of the CTE-matching material are not subjected to the drilling and epoxy-filling steps of the inventive process.
[0050] FIG. 3 a starts with a cross-section of the CTE-matching material 300 machined to the desired shape and thickness.
[0051] FIG. 3 b illustrates a cross-section of the CTE-matching material 300 after it has the appropriate holes created in it by, in this embodiment, mechanical drilling. Holes of this type may be created in the CTE-matching layer by a variety of methods including mechanical or LASER drilling. After they are created, the holes are then filled with a non-conductive epoxy 320 and the epoxy is allowed to dry. The drying and curing procedures and times vary depending on the type of epoxy used but will usually involve a thermal cycle with outgassing.
[0052] FIG. 3 c illustrates a cross-section of an embodiment of a PWB stack based on the inventive process. The CTE-matching layer 300 , containing an epoxy-filled hole 320 is the layer-2 metallization of the PWB stack in this embodiment. The dielectric layer 340 and lower substrate layer 360 separate the CTE-matching layer 300 from the top layer metallization 350 and the lower layer metallization 370 .
[0053] FIG. 3 d illustrates a cross-section of an embodiment of a completed PWB stack based on the inventive process. An electrically isolated via 390 has been created by drilling into the PWB stack in the location where the epoxy-filled hole 320 was created in the CTE-matching layer 300 .
[0054] After the via hole is created in the PWB, in this embodiment it is plated with copper 385 so that it will electrically connect the top and bottom metallization layers. Other methods of introducing conductive material into an electrical via hole include filling the hole with metallic paste, plating it solid with copper, or back-filling it with silver.
[0055] FIG. 3 d also illustrates the ablated cavities 380 that are created to allow components to be mounted directly onto the CTE-matching layer 300 . In this embodiment of the inventive process, the cavities were created through LASER ablation. Other methods for creating cavities where the CTE-matching layer is exposed for attaching components to it include mechanical routing.
[0056] FIG. 1 a illustrates the ablated cavities 75 in more detail. In this cross-sectional view, it is more clearly illustrated that the top metallization layer 25 and the dielectric layer 55 are both ablated away to create the cavities where components may then be attached to the CTE-matching layer. In this embodiment of the inventive process, a PWB for RF applications is being created. The dielectric layer 55 in this embodiment is made of a high-performance laminate chosen specifically for its dielectric properties whereas the lower substrate layers 70 may be made from less expensive material such as an epoxy resin bonded glass fabric (ERBGF) like FR-4, synthetic resin bonded paper (SRBP), ceramic, or Teflon. In other embodiments of the inventive process, there may be no need for a specific dielectric layer 55 and all the non-metal layers may be substrate layers 70 .
[0057] FIGS. 4 a - b present a comparison of two PWBs. FIG. 4 a is a PWB produced according to current processes and technologies while FIG. 4 b is a PWB produced according to an embodiment of the inventive process.
[0058] In FIG. 4 a , the PWB stack 430 illustrated is one intended for RF applications. The layer 2 metallization 400 has been exposed by ablating away regions of the top metallization and dielectric layers 420 . RF components 410 are attached directly to the layer 2 metallization 400 for purposes of RF grounding. The layer 2 metallization 400 is Copper and is between 0.7 and 1.4 mils thick, like all the metallization layers in the PWB. It does not provide any CTE matching or heat dissipation for the RF components, resulting in a reduced operating lifetime and creating a need for external heat sinks. FIG. 1 b depicts a PWB without a CTE-matching layer and with a top heat sink 3 and a bottom heat sink 6 and thermal vias 9 to channel heat up 9 - 2 to the top heat sink 3 and down 9 - 3 to the bottom heat sink.
[0059] In FIG. 4 b , the PWB stack 480 illustrated is also one intended for RF applications. This PWB, however, was created according to an embodiment of the inventive process. Here, the layer 2 metallization 440 has also been exposed by ablating away regions of the top metallization and dielectric layers 460 . In this embodiment, however, the exposed layer 2 metallization 440 is the CTE-matching layer 470 . The CTE-matching layer 470 introduced into the PWB in this embodiment of the inventive process is a Copper-Graphite composite material and is 40 mils thick. It provides a ground plane for the RF components 450 that are attached directly to it and also matches the CTE of the RF components. Further, because of its thickness, it is capable of not only spreading, but also dissipating the heat generated by the attached RF components 450 , eliminating the need for thermal vias and external heat sinks.
[0060] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
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The present invention relates to a method of manufacturing a printed wiring board (PWB) of the type depicted in FIG. 1, and to the resulting PWB. Such a PWB comprises a first substrate and alternating layers of a second substrate and a metal layer. The layer 2 metallization of the PWB is a thick layer of a composite engineered metal material having a configurable coefficient of thermal expansion (CTE) to provide CTE matching with respect to radio frequency (RF) components mounted on the PWB, and having substantial heat dissipation properties to dissipate heat generated by the RF components. This composite metal layer also provides a ground plane for the RF components.
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BACKGROUND OF THE INVENTION
[0001] Municipal sewage waste imposes significant environmental and handling costs, including damage to water and air quality. This problem has intensified with population growth and suburbanization. Significant time and energy inputs may be needed to process water and solids to (a) return clean water to surface waters and (b) render solid or liquid materials suitable for agricultural use.
[0002] In a standard process, wastewater enters the treatment plant and is treated via a series of large pools. In primary sewage pools, oil and grease are removed, and water in the waste begins to evaporate. In secondary pools, the water is further agitated and aerated. This promotes activity in the pool to release more water via evaporation and cause the waste to react to the air. In final pools, aeration continues, and treatment is concluded. The end wastewater product is malodorous but is only 1.5% solids on average.
[0003] In some locales, cities will arrange for the wastewater product to be hauled away, with it then being spread on fields as fertilizer. Environmental protection authorities often disfavor this handling because of risk to surface waters and groundwater as well as air quality. In addition, the waste may contain viruses and bacteria or other infectious microorganisms. Open field spreading of municipal waste can also result in municipal liability in the event of any environmental damage.
[0004] In some areas of the world, the processing of fresh fruit bunches of oil palm results in the generation of different types of residue. Among the waste generated, palm oil mill effluent (POME) is considered the most harmful waste for the environment if discharged untreated. POME is the wastewater discharged from the sterilization process, crude oil clarification process, and cracked mixture separation process. It results in clogging and water logging of the soil and kills any vegetation on contact. Currently, the most suitable, and frequently used, treatment method is a ponding system. However, ponding systems occupy a vast amount of landmass, have a relatively long hydraulic retention time, a bad odor, and difficult in maintaining the liquor distribution and biogas collection.
[0005] Access to an efficient source of biomass fuel is also a critical issue. Current biomass competition includes coal, wood pellets, natural gas and nuclear processes for production of energy. However, various markets, including Europe, have imposed fuel taxes based on carbon content (such as in coal and natural gas) or have mandated the use of clean energy sources such as biomass. Wood fiber resources are not sufficient to meet this demand. Processed human or animal waste products could provide a renewable and plentiful source of biomass fuel. However, current processing of such waste processing into fuel pellets involves substantial time, energy, transport fuel and labor inputs and charges. Use of these fuel pellets results in a net energy loss. With transport, the environmental issues are compounded because of the addition of truck fuel air pollution associated with moving heavy, high-moisture waste on the road.
[0006] Systems and methods are needed that (a) minimize human waste exposure to air and chance of waste release into surface water or groundwater and (b) reduce energy processing for both clean water and fertilizer and/or fuel pellets. Generally, a system is needed to efficiently and rapidly remove liquid from human waste and speed processing into clean water, fertilizer and/or fuel.
SUMMARY OF THE INVENTION
[0007] The system and methods as disclosed herein remove significant moisture content from human, animal, vegetable, and plant materials, yielding clear discharge water that can be returned to a sewage treatment plant. Some wastes can also yield fertilizer and an energy positive fuel source.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an example waste treatment train with a vacuum filter.
[0009] FIG. 2 illustrates example fuel pellet shapes.
[0010] FIG. 3 illustrates an example drum filter.
[0011] FIG. 4 illustrates an example of the current municipal wastewater treatment plant process.
[0012] FIG. 5 illustrates an example of the disclosed waste processing system.
DETAILED DESCRIPTION
[0013] Various embodiments will be described in detail with reference to the drawings, wherein like reference numerals represent like parts and assemblies throughout the several views. Reference to various embodiments does not limit the scope of the claims attached hereto. Additionally, any examples set forth in this specification are not intended to be limiting and merely set forth some of the many possible embodiments for the appended claims. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover application or embodiments without departing from the spirit or scope of the claims attached hereto. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting.
[0014] In general terms, the systems and methods described herein illustrate a waste processing system that uses a burnable filter aid to produce clean water, fertilizer concentrate and combustible energy pellets. In some embodiments, the waste processing system is portable.
[0015] The term “waste” refers to any type of human, animal, or plant waste that may be used in the system to produce clean water, fertilizer or fuel pellets. Examples of human materials include, but are not limited to, wastewater with human waste, food scraps, oils, soaps, and chemicals in it. Animal material may include, but is not limited to, slaughterhouse byproducts known as clarifier sludge and animal manure. Clarifier sludge contains non-bone parts of the animal such as blood, manure, and other fatty parts. Plant material may include, but is not limited to, plant parts that come from vegetable processing and packing plants such as rejected vegetable pieces that are split, damaged, or spoiled as well as byproducts that, when processed, cast off a paste waste product. This type of plant waste can include sugar beets, rice hulls, wood shavings, or bedding that may normally be mixed with animal waste. Plant waste material may also include palm oil mill effluent (POME).
[0016] The term “burnable filter aid” refers to a filter aid that is combustible. One example is a cellulosic filter aid. The filter aid may be included in an energy pellet that is produced using the processes described below. The energy pellet, including the filter aid, may be burned and used as a substitute for other energy sources such as, but not limited to, coal, wood pellets, natural gas, or nuclear processes. An example fuel pellet shape is illustrated in FIG. 2 .
[0017] The term “slurry” refers to waste that has been liquefied, including with additional water, in the processes described herein. Slurry is sometimes referred to as municipal sludge, packing plant clarifier sludge, or vegetable processing plant liquefied waste.
[0018] The term “microwaving technology” refers to the use of a microwave to further dry a raw pellet by transforming the remaining liquid hydrogen dioxide molecules in the pellet into a gaseous state, and then clearing the molecules from the area around the pellet by using a fan. Microwaving may kill pathogens and reduce the possibility of public health risks. In one embodiment, the microwave may be a 1000-watt minimum microwave unit.
[0019] FIG. 4 illustrates a typical municipal wastewater treatment process, which results in biogas, discharge from filtration, and sludge tank products. Biogas and filtration products are reusable, but sludge tank products are typically disposed of at a landfill or used as fertilizer. More specifically, raw effluent proceeds through a screen, an oil and grease separator, and an equalization tank before making it to a primary settling tank or primary clarifier. From the primary clarifier, the products can either go to an anaerobic digester or sludge tank. Products from the sludge tank are typically then transported to a landfill or used as fertilizer. Products from the anaerobic digester can go through an aeration process, can go to the sludge tank, or are biogas. From the aeration process, products then go through the secondary clarifier. At this point, the product goes to the sludge tank, is discharged, or goes through ultra filtration. After ultra filtration, the ultra filtration rejects go to the sludge tank. Other products can either be discharged or can go through a reverse osmosis process. Reverse osmosis rejects go to the sludge tank. Other product can be recycled back to a mill.
[0020] FIGS. 1 and 5 illustrate embodiments of the current system and how it uses products from the sludge tank to create more usable end products. In one exemplary embodiment of the method described herein, as illustrated in FIG. 1 , the treatment train process starts with waste, which is fed from a source 102 and is 6% solids or less. If the waste is more than 6% solids, it can be diluted using previously processed wastewater. High-pressure injectors, which are built into a pump 104 , liquefy the waste as it passes from the source 102 , through the pump 104 , and into a process tank 106 . In the process tank 106 , a mixer suspends and mixes the waste into a slurry material. While the slurry is mixed into the process tank 106 , pH adjustments can be made. The process tank 106 feeds a rotary vacuum drum filter 108 . The drum filter 108 uses a filter aid pre-coat to separate the solids from the liquid.
[0021] The filter aid, which can be made of various materials, including diatomaceous earth, Perlite, or in a preferred embodiment, cellulosic material, is pre-coated onto the external surface of the drum. Pre-coating takes place by putting a filter aid slurry in a basin outside of the drum, activating the drum vacuum, and building up a filter aid base on the outside of the drum while the remainder of the filter aid slurry proceeds to the inside of the drum. The drum filter vacuums the pre-coat onto the drum until it reaches the desired filter aid depth. Once this depth is achieved, the drum is ready to receive the slurry material for processing. Typical filter aids, such as diatomaceous earth or Perlite, may be compostable, but are not burnable. This typically renders the post-processing solid material useless for fuel pellets. The use of burnable filter aid, such as cellulosic material, thus provides a significant advantage.
[0022] After pre-coating the drum and feeding the waste slurry from the process tank 106 , the vacuum force in the drum filter 108 is activated. This force pulls the slurry material onto the surface of the drum, with solid materials captured by the filter aid and separated into a solids tank 110 through the use of an indexing knife, which scrapes off the solid in small increments. The liquid passes through the filter aid and into the interior of the drum. The liquid is then pumped to the process liquid bulk tank 112 for reuse. Any excess liquid overflows the process liquid bulk tank 112 and goes into the value-added fertilizer container 114 . The dry solid, filtered with cellulosic material, can be processed further as needed for final use as an energy pellet. The liquid can be converted to a concentrated fertilizer additive or can be run through an additional treatment to be rated as safe, clean, surface water discharge.
[0023] With the above process, the moisture content of the initial slurry can be reduced to 20-25%. In one embodiment, some portions of the waste material may be processed twice through the treatment train process shown in FIG. 1 in order to further concentrate the liquid and remove additional water.
[0024] In one embodiment, a secondary drying process 502 takes place using natural gas heat in a natural gas oven. This drying process creates steam and a dried cake with a 9-10% moisture level. In another embodiment, the treatment train process can be coupled with infrared or microwaving technology to lower the moisture content even further, potentially to 5%, via exposure to a microwave energy source. This would produce higher-grade energy pellets and could also kill pathogens or microorganisms that may be present in the slurry or post-processing solid or liquid materials.
[0025] Alternatively, the treatment train process can be coupled with a high-speed punch press instead of microwaving technology. The press can accept pellet material in sheet form and can punch or hammer the sheet to create puck-shaped pellets out of the accepted material by pressing and heating the remaining moisture out of the material. The product can self-fuse due to the heat and may not break apart or flake.
[0026] In one embodiment, the treatment train process can separate the water from the waste onsite at a sewage treatment facility and the clear water can be returned to the sewage treatment facility where it can be used to flush a city's water system.
[0027] The treatment train process described herein may be portable or stationary and can process waste from a sewage treatment facility, waste from a Concentrated Animal Feeding Operation (CAFO), vegetable waste, or plant waste onsite where the waste is collected. This portability provides a unique advantage, opening up a range of facilities that normally would not have access to drum filtration and also, in the case of municipal waste, an ability to return post-processing water on-site back to the water plant. This is a significant environmental and process enhancement.
[0028] In one embodiment, the post-processed energy pellet may be combined with other biomass to increase the British Thermal Unit (BTU) value. Alternatively, other biomass may be added during the treatment train process to create an energy pellet that has an immediate increased BTU value.
[0029] In one embodiment, acid or polymers may be added to the waste in the process tank 106 during a portion or all of the treatment train process. The use of acid or polymers at the beginning of the treatment train process may force metals and corrosives to collect in the liquid portion when the liquid and solid parts are separated in the drum filter 108 . If metals and corrosives collect in the liquid portion, the liquid may be manipulated so as to lower the pH and extract the metals. This would leave only leave the water, which, if desired, can be returned to the sewage treatment facility.
[0030] The disclosed system reduces land usage and cost, reduces operating costs and retention times, mitigates bad odors, mitigates fluctuating load factors on digesters, results in the recovery of clean water and renewable fuel in the form of bio-sludge pellets, and results in waste heat availability.
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A device and method that removes moisture from human, animal, vegetable, and plant materials, yielding clear discharge water that can be returned to a sewage treatment plant. Some wastes can also yield fertilizer and an energy positive fuel source.
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RELATED APPLICATIONS
The present application is a continuation of U.S. Prov. No. 60/841,270 and claims a priority benefit to its Aug. 31, 2006 priority date. This application incorporates all the subject matter disclosed in ('279) as if it is fully rewritten herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a pet toy and, more specifically, to a pet toy that is removably secured to a home fixture such that a retraction mechanism delivers an opposing force that reels the toy inward, thus interactively challenging the pet.
2. Description of the Related Art
Pet toys are categorized as either static toys or dynamic toys. The former comprises no means of motion, but the latter comprises such a means. This means is directed towards a sending of the toy in an uncontrolled direction and towards a duration in which the motion occurs. The motion limitations of static toys cause pets to quickly become bored with them. Dynamic toys, on the other hand, are more attractive to pets because they invoke the pet's instinct to chase and to engage the toy, i.e., to actively play with the toy; yet, a very nature of their being “uncontrolled” causes many of these toys to wedge between household furnishings. Once the toys are caught between furniture, their interactive features are lost.
A need is felt for a pet toy that both evokes the chasing instinct of a pet, but one that is also limited in range so that it doesn't lodge between furniture. It is envisioned that a means to limit the present toy's range is a mechanism that contains a reel that winds a stimulated prey away from the pet. A search of the prior art reveals no patents that teach the claims of the present invention; however, the following references are considered pertinent:
U.S. Pat. No. 5,743,215 to Zeff teaches a pet toy attached to a pole and a reel assembly, wherein the toy is manually reeled away from a pet by means of a crank;
U.S. Pat. No. 5,782,207 to Goodham teaches an interactive pet toy that comprises a toy mouse that retracts into a tubular housing by means of a cable, wherein the toy is manually operated by the cat's owner using a handle;
U.S. Pat. No. 5,467,740 to Redwine similarly teaches a toy or a training object reeled in from a lure that is cast, wherein an adjustable drag mechanism provides a means to selectively increase or decrease drag on the anchor line; and,
U.S. Pat. No. 5,947,790 to Gordon teaches a line that is receivable on a rotating spool drivingly connected to a motor.
While the present invention incorporates some of the features taught in the foregoing references, others are distinct enough so as to distinguish it over the prior art. More specifically, the most of the references require a pet owner to hold a handle portion so that an attached toy is manually cranked in. The present invention comprises a pet toy that is removably secured to a home fixture such that a wind-up mechanism provides a pet with an opposing force to play with. When a pet owner is not at home, it is anticipated that the pet will pounce a toy that resembles a natural prey in appearance. When the pet grabs the toy to carry it away, the wind-up mechanism delivers an opposing force that reels the prey inward. So, the pet is essentially engaging in a tug-of-war challenge with the wind-up mechanism. Alternatively, the pet owner can pull the toy comprises at the end of the reel to maximum length. The owner then activates a switch that causes the toy to reel towards the mechanism, thus stimulating the pet to chase it.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a pet toy that interactively engages a pet.
It is an object that a dynamic movement feature of the present toy is that it travels generally linear.
It is an object that a further dynamic movement feature of the present toy is a resistance to the pet playing with it.
It is an object of the present invention to provide a mechanism that limits the range of physical space through which the toy can be utilized.
It is a further object to provide a retracting mechanism by which a variety of toys can be attached.
It is a further objective that the toy attached to the retracting mechanism comprise a pocket in which catnip or another pet olfactory stimulant is contained.
It is an additional object that the mechanism removably secures to a home furnishing, i.e., a table leg, etc.
It is envisioned that the foregoing objects are accomplished by the various embodiments of the present invention, wherein an attractive cat toy, s.a., one that resembles a prey, a bone, etc., is removably tethered to a mechanism that mechanically winds the toy towards it. The mechanism internally contains a reel having the attractive toy attached to its distal end. An opposite side of the mechanism comprises a means to removably secure it to a home fixture, s.a., furniture. Therefore it is anticipated that the present invention provides the advantages of an interactive toy that is limited in travel range so that it cannot get lost between and underneath furniture.
It is a final object of this invention to provide all of the advantages that the foregoing objects entail.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and the features of the present invention are better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which:
FIG. 1 is a side view of a pet toy according to a preferred embodiment of the present invention, wherein an attractive toy is connected to a retraction mechanism by means of a reel;
FIG. 2 is view of the internal workings of the retraction mechanism that is part of the pet toy shown in FIG. 1 ; and
FIG. 3 is side view of the retraction mechanism spool, wherein it comprises locking notches.
DESCRIPTION OF THE PREFERRED EMBODIMENT
1. Detailed Description of the Figures
FIG. 1 is a pet toy according to a preferred embodiment of the present invention, wherein an attractive toy 1 is connected to a retraction mechanism 3 by means of a reel 2 . The attractive toy 1 is shown in FIG. 1 to be a mouse, but it is not limited to any toy that resembles a natural prey. The attractive toy 1 may rather comprises a bone (for dog's), a chew toy, or any other toy that attracts pets. Because mice and birds are common prey hunted by cats, many of these attractive toys 1 may take a form that resembles one of these natural preys, like the mouse in the figure. U.S. Pat. No. 6,371,053, to the present inventor, is such an attractive toy 1 , wherein a simulated, cloth mouse comprises a sound chip that emits a prerecorded sound in response to its engagement. It is anticipated that the mouse shown in FIG. 1 emits a sound that more closely replicates the vocalizations of mice. The present invention incorporates all the subject matter of ('053) as if it is fully rewritten herein.
The attractive toy 1 connects to the reel 2 by means of a quick disconnect mechanism 8 . The disconnect mechanism 8 may comprise any means well known in the art to engage two parts. It may comprise for example, a pair of threads that mate with corresponding threads on the attractive toy 1 , a hook-and-loop fastener combination, a loop and a tie combination, etc. The means is not limited to the foregoing disclosed. It is important that the disconnect mechanism 8 is durable and strong enough to withstand a tug-of-war challenge with a pet. When the pet pulls on the attractive toy 1 , the disconnect mechanism 8 competes with the pet so that the attractive toy 1 is not disconnected from the reel 2 and taken away.
The reel 2 is shown in the figure at an extended position, i.e., pulled away from the retraction mechanism 3 . The reel 2 is wound inward by means of the retraction mechanism 3 to pull the attractive toy 1 towards it. A detailed teaching of this process will follow.
The retraction mechanism 1 comprises a means to secure it to a stationary object 6 on either an adjacent or a side opposite that of where the reel 2 travels. The means to secure 6 is not limited to the through loop 4 shown connected to the means 6 rung about a stationary object 5 (shown in FIG. 1 ), but it may rather comprise any other means of attachment known in the art. The stationary object 5 may be either furniture or home fixtures. For example, the stationary object 5 shown in FIG. 1 is a table leg or a chair leg.
Placed on an exterior of retraction mechanism 3 are alternate start and stop switches 16 , 17 . These switches 16 , 17 are used to activate the internal components of the present invention. FIG. 2 is view of the internal workings of the retraction mechanism 3 that is part of the pet toy shown in FIG. 1 . The reel 2 winds about a spool 11 that is connected to an axis 13 . The axis 13 connects to the internal housing of the retraction mechanism 3 by means of a rounded depression 15 having a slightly smaller circumference than that of the axis 13 , wherein an interference fit secures the axis 13 to the housing. Alternatively, the distal end of the axis 13 may comprise male threads (not shown) that mate with corresponding female threads (not shown) within the depression. The opposing distal end of the axis 13 is also supported to an opposing surface of the internal housing of the retraction mechanism 3 . A torsion spring 12 is formed about the axis 13 , wherein an inter-spiral end of the spring 12 connects to the axis and an opposite end of that spring 12 connects to the internal housing of the retraction mechanism 3 . The switches 16 , 17 are friction switches that slide between the housing of the retraction mechanism 3 and the reel 2 .
FIG. 3 illustrates an alternative embodiment of the internal workings of the retraction mechanism 3 , where locking notches 18 work in conjunction with the switches. In this embodiment, the spool 11 comprises notches 18 about its circumference. A level switch 17 fits within a slot formed in the housing of the retraction mechanism 3 slides linearly upwards and downwards, as shown in FIG. 3 . The switch 17 is designed to slide into and positively engage a given notch 18 of the spool 11 . FIG. 3 further illustrates first that the reel 2 wraps about spool 11 from the axis outwards.
2. Operation of the Preferred Embodiment
To operate a preferred embodiment of the present invention, reference is given to FIG. 1 , the attractive toy 1 is shown fully extended from the retraction mechanism 3 . As the attractive toy 1 extends away from the retraction mechanism 3 , it unwinds about the spool 1 . This extension simultaneously causes the torsion spring 12 to wind tightly about the axis 13 , thus generating an opposite torque about the axis 13 and the spool 11 . Because the torsion spring 12 is attached to both the axis 13 and the internal housing of the retraction mechanism 3 , it winds up tightly about the axis 13 as the axis rotates. The resultant torque is applied to the spool 11 , whereupon it translates itself into a retraction force upon the reel 2 . When the attractive toy 1 is released from a pet's grip, the retraction force pulls the attractive toy 1 towards the retraction mechanism 3 .
As is noted in FIG. 1 , the retraction mechanism 3 comprises a small loop 4 connected to the housing of retraction mechanism 3 . The through loop 4 is shown secured to a ring 6 looped about a bottom of a stationary object 5 . The use of the securement ring 6 provides a means for the retraction mechanism to be fixed at a location. As such, when the attractive pet toy 1 is pulled away from the retraction mechanism 3 , the retraction mechanism remains affixed to the stationary object 5 . When the pet toy 1 is released, it moves back towards the retraction mechanism 3 under the retraction force conveyed by string 2 .
The motion of the pet toy 1 can be stopped utilizing the stop/start friction switch 16 that slides between the housing of the retraction mechanism 3 and the reel 2 . This is accomplished because the body of the friction switch 16 wedges between the reel 2 and the housing. Friction locks the reel 2 in a fixed location. This is a particularly useful feature because when the retraction force is disabled, a pet can play with the attractive toy 1 simply tethered at an adjustable, extended distance away from the retraction mechanism 1
In an alternative version of the workings of this invention, as noted in FIG. 3 , the motion of the pet toy 1 can be stopped by means of a stop/start switch 17 that slides between the housing of the retraction mechanism 3 and into one of the notches 18 comprised on the spool 11 . In this embodiment, the sliding of the switch 17 into a notch 18 locks the spool 11 to prevent it from rotating and thus removes the force of retraction on reel 2 . This alternate stop/start switch feature is particularly useful as well: the use of the switch 17 provides a means for the length of the reel 2 to be maintained at a fixed length. At a fixed length, the pet can play with the attractive toy 1 within a limited range from the retraction mechanism 3 so that the toy is not lost between and underneath furnishings.
It is finally anticipated that the attractive toy 1 comprise a pocket (not shown) in which catnip or another olfactory stimulant is added. The pocket secures shut by means of various methods well known that include, but are not limited to, a zipper, Velcro, or a button.
The present invention may be constructed of a variety of materials. Although the connection between the retraction mechanism 3 and the pet toy 1 is shown as a reel 2 , the actual connection may alternately be by way of a chain, a flexible cord (such as fishing line), or a flexible tape.
The foregoing description is included to illustrate an operation of the preferred embodiment and it is not meant to limit the scope of the invention. As one can envision, an individual skilled in the relevant art, in conjunction with the present teachings, is capable of incorporating many minor modifications that are anticipated within this disclosure. The foregoing descriptions of the specific embodiments of the present invention are presented for the purposes of illustration and description. They are neither intended to be exhaustive nor to limit the invention to the precise forms disclosed and, obviously, many modifications and variations are possible in light of the above teaching. The embodiments are chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Specification and Drawings appended hereto and their equivalents. The following Claims are meant only to be exemplary.
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The present invention generally relates to a pet toy and, more specifically, to a pet toy that is removably secured to a home fixture such that a retraction mechanism delivers an opposing force that reels the toy inward, thus interactively challenging the pet. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.
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This application is a continuation of application Ser. No. 494,346, filed May 13, 1983, now abandoned.
This invention relates to insulating shades for windows and more particularly comprises a new and improved insulating shade with a removable cover fabric which enables the owner to change or clean the cover fabric as the owner wishes.
Conventional insulating shades are usually made up of a layer of insulating material and a separate cover fabric which are sewn, welded or otherwise adhered permanently together. Frequently, the shades are sold with the cover fabric attached, and the purchaser is offered only a limited selection of cover patterns. Other insulating shades are sold without the cover fabric, and the purchaser separately acquires the cover fabric and permanently secures it to the insulating layer.
Because the cover fabric in conventional prior art insulating shades is permanently secured to the insulating layer, the cover fabric cannot be changed or be cleaned independently of the insulating layer without very considerable expense and inconvenience to the owner. Moreover, the cover fabric cannot be adjusted for stretching of one layer with respect to the other nor for any wrinkles that may arise due to distortion of the insulation or fabric.
One important object of the present invention is to enable a person to remove the cover fabric from the insulating layer in an insulating window shade so that the cover fabric may be independently washed, cleaned or replaced.
Another important object of this invention is to provide a cover fabric which conceals the insulating layer and which may be adjusted to compensate for stretching or to smooth out any wrinkles that may appear.
In accordance with the present invention, the objectives are achieved by constructing the shade so that the cover fabric is not permanently attached to the insulating layer. This allows the cover fabric to be adjusted or be removed for cleaning or for replacement. And because the cover fabric is not permanently secured to the insulating material, the owner is allowed to use virtually any type of covering fabric. There are no constraints imposed by sewing, welding, or other attachment methods.
In accordance with the preferred form of this invention, the insulating window shade assembly includes a pair of spaced brackets that are adapted to be mounted on the opposite top sides of the frame of the window to be insulated. A roller with insulating material is mounted on the brackets, and the material is adapted to be drawn over the inside of the window. The roller for the insulating layer is operated by a pull cord counterwound on a pulley attached to the roller. A second roller carrying a cover fabric is mounted on the brackets and is disposed on the inside of the insulating layer when the insulating layer is drawn. The cover fabric is substantially the same width as the insulating material so as to cover the inside of the insulating layer when both sheets are drawn over the window. An idler roller is also mounted on the brackets inwardly of the insulating material, and the cover fabric extends about this roller. The idler roller supports the cover fabric very close to the insulating layer. The bottoms of the insulating layer and cover fabric are detachably secured together by a Velcro or similar type of fastener. The cover fabric roller is spring-loaded to retract the cover fabric, and the cover fabric is held in tension when the insulating sheet is drawn so that the cover sheet lies closely adjacent to and smoothly over the insulating layer. Channels on the sides of the window seal the edges of the insulating layer and overlap the side edges of the cover fabric to provide the shade with a finished appearance. A strip is carried on a batten at the bottom of the shade to seal against the window sill, and a second strip at the top of the insulating layer cooperates with the idler roller to push the insulating layer against the window trim to form a seal at the top of the window.
This invention will be better understood and appreciated from the following detailed description of one embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings.
BRIEF FIGURE DESCRIPTION
FIG. 1 is a front view of an insulating window shade assembly constructed in accordance with this invention, shown mounted on a window and in drawn position;
FIG. 2 is an enlarged fragmentary vertical cross-sectional view through the shade assembly and window, taken along section line 2--2 of FIG. 1;
FIG. 3 is a fragmentary perspective view of the bottom of the shade assembly;
FIG. 4 is a horizontal cross-sectional view of the shade assembly and window, taken along section line 4--4 of FIG. 1;
FIG. 5 is a detailed view of the pull cord subassembly of the invention;
FIG. 6 is a cross-sectional detail view of the bottom of the shade assembly; and
FIG. 7 is a plan view of a portion of the Velcro-type hook fabric used in the invention.
DETAILED DESCRIPTION
In FIG. 1 the shade assembly 10 is shown mounted on a window frame 12. The frame 12 includes a sill 14, left and right jambs 16 and 18, and a lintel 20. The window itself may be any variety; the window configuration per se is not part of the present invention.
The shade assembly 10 is mounted on the faces of the jambs 16 and 18 and lintel 20 and includes a valance 21, edge tracks 22, and shade 23 which has insulating layer 24 and cover fabric 26. The assembly also includes a pair of brackets 28, roller 30 for the insulating layer, cover fabric roller 32 and idler roller 34, all supported at the top of the window frame 12, and a batten 36 at the bottom of the shade. These several parts of the assembly along with their functions are described in detail below.
The valance 21 shown in FIGS. 1 and 2 includes a front panel 40, a top wall 42 and a short rear wall 44. The rear wall 44 may be attached directly to the lintel 20 so as to fix the valance in place. It is to be understood that the configuration of valance shown is not critical to the present invention, and it may take a variety of different forms. One bracket 28 is mounted behind the front panel 40 of the valance 21 at each end of the valance, and the brackets 28 may be connected either to the valance itself or to the lintel 20. It is within the scope of this invention that the brackets 28 be connected directly to the window frame and the valance 21 be hung from the brackets.
Roller 30 which carries the insulating layer of material 24 is supported for rotation on the brackets 28 and is confined within the valance 21 behind front panel 40. Roller 30 may be of conventional construction and is operated by the pull cord system 50 shown in FIG. 5. The pull cord system includes a pulley 52 coaxial with and secured to one end of roller 30, and the roller and pulley rotate together. Pull cord 54 is wound on the pulley 52 in the counter direction of the insulating shade material 24 on roller 30 so that as the insulating material is drawn off roller 30, the pull cord 54 is wound onto pulley 52. Pull cord 54 extends about jamb roller 56 supported by yoke 58 on the jamb of the window so as to releasably lock the shade in any desired elevation.
The insulating shade material 24 may be made of a variety of different materials. In the preferred form, the material 24 is quilted and is made up of a multi-layered laminate including layers of polyester fabric, batting and polyester film. Normally, the insulating material is quite bulky and consequently requires substantially more space about the roller 30 to accommodate the material than is required for the cover fabric 26 wound about roller 32.
As shown in FIG. 2, cover fabric roller 32 is supported from brackets 28 below roller 30. Cover fabric 26 which may be made of any type of material and be of any weight is wound counterclockwise on roller 32 and extends from roller 32 over idler roller 34 and down the front of the window on the inside of insulating material 24. The insulating material 24 is wound clockwise about the roller 30, and it also extends behind the idler roller 34 on the window side of cover fabric 26. Roller 32 in the preferred form is biased as suggested by the mechanism 33 in FIG. 2 so as to constantly exert a tensioning pull on the cover fabric in an upward direction. This action of the roller 32 is counteracted by the connection between the cover fabric and the insulating material as shown in FIG. 3 and described in detail below.
The width of the cover fabric 26 is substantially the same as that of the insulating material 24 and it conceals the insulating material. The insulating material has a beaded edge 62 which is disposed in the channel 64 defined by legs 66 and 68 of the edge track 22. As shown in FIG. 4, bead 62 is disposed inside the channel 64, and its diameter is larger than the slot 70 defined by the inner edges of the legs 66 and 68. This arrangement forms a seal between the insulating material and the edge track so as to prevent cold air from flowing about the sides of the insulating material to the interior of the structure.
Edge tracks 22 on each window jamb include an inwardly extending flange 72 which overlaps the edge 74 of the cover fabric 26 so as to retain the side edges of the cover fabric closely adjacent the insulating material, prevent the edges from curling, conceal the insulating material 24 and otherwise provide the insulating shade with a finished appearance. As shown in FIG. 4, the edge track 22 is mounted on the front face of the jamb 16 forming part of the window trim.
Batten 36 at the bottom of the shade includes a front panel 80 and rear panel 82 with interfitting flanges 84, 86 and 88 which sandwich and encase the lower edge of the insulating material 24. The flange 88 is barbed to hold the parts together. A weight 90 is contained within the panels 80 and 82 of the batten so as to cause the shade to hang smoothly. Beneath the weight is a foam strip 92 that extends below the lower edges of the panels 80 and 82 and is intended to form a seal with the window sill 14 when the shade is fully drawn. The lower surface 94 of the foam strip 92 may be inclined slightly so as to conform to the inclination of the sill.
The inner panel 80 of the batten carries an inwardly extending flange 96 provided for the convenience of the operator. The flange 96 enables the operator to grasp the batten to draw the shade downwardly when the window is to be covered.
A strip 100 of hook-bearing Velcro-type material is provided at the bottom of the insulating material 24 and extends across the bottom of the shade. As shown in FIG. 7, the face of the strip 100 carries the hook members 101 on half the strip width while the other half is bare. The strip is not sewn or otherwise directly attached to the insulating material 24 but rather it is held in place by being clamped along with the bottom of the insulating material between the panels 80 and 82 of the batten 36. As is evident in FIG. 6, the part of the strip 100 which does not bear the hook members extends below the edges 104 and 105 of the panels 80 and 82 of the battens. Therefore, there are no hook members to interfere with the clamping of the strip.
It is very desirable that the strip 100 not be stitched or otherwise secured directly to the insulating material 24. When it is secured to that material, the strip tends to pull the bottom of the insulating material to one side with respect to the tracks 22, and this interferes with the seals between the track and the shade so as to lessen the effectiveness of the shade.
A complementary strip 102 of looped fabric is secured to the bottom of the cover fabric 26 so that the cover fabric may be secured at the bottom to the insulating material. The Velcro-type strips 100 and 102 face one another and therefore are not visible when the cover fabric is mounted in place over the insulating material. The cover fabric 26 should be just long enough to touch or slightly overlap the upper edge 104 of the inner panel 80 of the batten so as to give to the shade a finished appearance.
A second foam strip 110 is carried by the insulating material 24 at the top of the shade. The foam strip 110 is disposed on the side of the insulating material away from the window and is oriented so that it lies immediately behind the idler roller 34 when the shade is fully drawn. The foam strip 110 forces the insulating material against the window lintel 20 by virtue of its cooperation with the idler roller 34 so as to cause the insulating material to form a seal at the top against the window trim. The foam block also forms a seal between the insulating material and the cover fabric when the block is pinched behind the idler roller.
From the foregoing description of the shade, it is apparent that the cover fabric 26 may be removed from the shade assembly merely by opening the Velcro connection at the bottom of the shade above the batten 36 and winding the fabric onto the roller 32. The cover fabric and roller 32 may be dismounted from the brackets 28, and the cover may then be removed for any purpose and be readily changed if desired. This feature also enables the cover fabric and the insulating material to be cleaned separately, which is particularly desirable if the cover fabric and insulating material are different materials and therefore require different cleaning or washing processes. Of course the owner, if desired, may replace the cover fabric with another merely by removing the fabric from the roller 32 and loading the new fabric onto it. Thus, the owner is afforded complete flexibility.
It will also be apparent from the foregoing description that the cover fabric 26 with the valance 21 and tracks 22 conceals the insulating fabric. Furthermore, the bottoms of the cover fabric and insulating materials may be separated along the batten so that the cover fabric may be smoothed out if wrinkles or other distortions of the fabric occur for any reason. Consequently, the shade may always have a fresh, smooth look.
Because numerous modifications may be made of this invention without departing from its spirit, it is not intended to limit the scope of this invention to the single embodiment illustrated and described. Rather, it is intended that the scope of this invention be determined by the appended claims and their equivalents.
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An insulating window shade assembly includes a first roller carrying an insulating shade and a second roller carrying a cover fabric. The shade and cover fabric are supported in essentially face to face relationship, and their bottoms are secured together by a Velcro-type fastener. The cover fabric conceals the insulating shade, it may be removed from the shade for cleaning or may be changed and it may be adjusted for smoothness and to compensate for any stretching which occurs in the materials.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a luminaire that has a plate-shaped optical waveguide, and first illuminants arranged on one or more narrow sides of the optical waveguide and designed to couple light into the plate-shaped optical waveguide, the light coupled into the optical waveguide being emitted via a flat side of the optical waveguide in a first radiating direction of the luminaire.
2. Related Technology
Such a luminaire is known from DE 197 55 658 A1 by the applicant, and is sold under the designation AERO waveguide luminaire. This luminaire is generally very popular, since it is characterized by an extremely flat shape and fulfils the requirements of modern office situations. The luminaire can be arranged freely in the room, and makes reflection-free working possible on vertical or strongly inclined screens, since the radiated light is emitted homogeneously over the whole flat side of the plate-shaped optical waveguide element. Since it is impossible to look at the illuminants directly from below, the luminaire also satisfies the highest aesthetic demands.
The luminaire disclosed in DE 197 55 658 A1 can be in such a form that the light of the illuminants is partly radiated upward as indirect lighting. It is also generally known that light which is radiated via an optical waveguide element has less intensity compared with directly radiated light. Accordingly, in the case of the luminaire described here, the indirect portion of the light, which is radiated upwardly, has a higher intensity than the portion of the light which is radiated downwardly via the optical waveguide element. This is usually seen as a disadvantage of the luminaire, since the coefficient of lighting utilization is very small, because of the inefficient direct component.
A further luminaire known from the prior art is disclosed in DE 10 2005 005 454 A1. This luminaire has discharge lamps as first illuminants, the light of the discharge lamps being coupled into a light pipe and radiated by it in different directions. Also, in a preferred embodiment, the luminaire has light-emitting diodes (LEDs), which are used to generate color effects. The light radiated upwardly from the light pipe for indirect lighting is mixed with the light of the LEDs.
SUMMARY OF THE INVENTION
The invention overcomes the disadvantage stated in relation to the luminaire disclosed in DE 197 55 658 A1, while retaining the advantageous properties of this luminaire.
According to the invention, therefore, a luminaire is has a plate-shaped optical waveguide and first illuminants arranged on one or more narrow sides of the optical waveguide and designed to couple light into the plate-shaped optical waveguide, wherein the light which is coupled into the optical waveguide is emitted via a flat side of the optical waveguide in a first radiating direction of the luminaire, the first illuminants are formed by multiple LEDs, and the luminaire also has second illuminants and a reflector arrangement which is associated with them, and via which the light of the second illuminants is emitted in a second radiating direction which is opposite to the first radiating direction.
The luminaire according to the invention differs from luminaires which are known from the prior art in that the efficiency of the direct lighting was significantly increased. In particular, it has turned out that by using LEDs for direct lighting via an optical waveguide, the coefficient of lighting utilization of the direct component can be decisively increased.
Further advantages of the luminaire according to the invention are the extremely flat shape and a homogeneous light profile, since the light is radiated evenly over the whole flat side of the optical waveguide.
The luminaire according to the invention is preferably a pendant luminaire which can be fixed to a ceiling. However, the luminaire can also be fixed to a wall.
Preferably, on the narrow sides of the plate-shaped optical waveguide, onto which the light of the first illuminants is coupled, a structure for coupling the light in evenly is formed. For this purpose, the narrow sides of the plate-shaped optical waveguide, onto which the light of the first illuminants is coupled, are in such a form that they each form, directly in front of each LED, a pyramid-shaped structure with an inwardly curved peak.
Preferably, the narrow sides of the plate-shaped optical waveguide in regions of the coupling-in structure, and the flat side, and the opposite side of the optical waveguide in regions of the coupling-in structure, are in reflecting form. In this way, light beams which are radiated from the LEDs at very steep angles are reflected back into the optical waveguide.
Also, the narrow sides of the plate-shaped optical waveguide can be overlapped by a reflector, which in regions of the coupling-in structure has recesses through which the first illuminants extend into the coupling-in structure.
The second illuminants preferably have at least one discharge lamp. However, using a different illuminant, e.g. incandescent bulbs or LEDs, is also conceivable here. The light of the second illuminants is radiated as indirect lighting on the upper side of the luminaire.
In a preferred embodiment, the first illuminants have multiple LEDs in at least two different colors. In this way, different color effects can be achieved with the luminaire, in particular it is made possible to set the color temperature of the direct light. Alternatively, it is also possible to use LEDs which emit white light.
Greater flexibility can also be achieved if the two illuminants can be controlled separately from each other, it being possible to set settings such as light quantity and light color for both illuminants separately.
To achieve even radiation of the light, on the opposite side of the plate-shaped optical waveguide to the flat side of the plate-shaped optical waveguide that is provided to emit light, a structure at which the light is scattered can be printed on. In this case, it is also advantageous if the distances between the structure become narrower towards the middle of the plate.
Preferably, on the opposite side of the plate-shaped optical waveguide to the flat side of the plate-shaped optical waveguide that is provided to emit light, a reflector is provided that reflects the light which emerges from the optical waveguide oppositely to the first radiating direction back into the optical waveguide, so that it emerges on the desired flat side of the optical waveguide.
Behind the plate-shaped optical waveguide, Seen in the first radiating direction, a translucent plate with an anti-glare structure or diffuser is preferably arranged, in which case, seen in the first radiating direction, a further, plane and translucent closing plate can be arranged behind this plate. The anti-glare structure or diffuser removes glare from the light emitted by the luminaire in the first radiating direction. Accordingly, the luminaire is suitable for use in rooms with strongly inclined displays. Unwanted reflections on the displays are avoided, and the luminaire can be arranged anywhere in the room.
Also, in a preferred embodiment, the plate-shaped optical waveguide is held by at least two opposite supporting members, the holders for the first and second illuminants being arranged in these supporting members. With such an arrangement, it is impossible to look directly at the illuminants.
BRIEF DESCRIPTION OF THE DRAWINGS
Below, the invention will be explained in more detail on the basis of the attached drawings.
FIG. 1 shows a cross-section of the luminaire according to the invention;
FIG. 2 shows a plate-shaped optical waveguide;
FIG. 3 shows an LED, and the structure of a lateral surface of a plate-shaped optical waveguide;
FIG. 4 shows a schematic cross-section through the plate-shaped optical waveguide;
FIG. 5 shows a first embodiment of the luminaire according to the invention, in a perspective view from below;
FIG. 6 shows the luminaire shown in FIG. 5 , in perspective plan view;
FIG. 7 shows a luminaire according to the invention, in a modified version, in a perspective view from below;
FIG. 8 shows the luminaire according to FIG. 7 , in perspective plan view;
FIG. 9 shows a view of an alternative optical waveguide from above; and
FIG. 10 shows a cross-section through the optical waveguide shown in FIG. 9 , along the connecting line AA.
DETAILED DESCRIPTION
The luminaire 1 according to the invention is shown in FIG. 1 in cross-section. This luminaire 1 has first illuminants, which according to the invention are LEDs 2 . The light of the LEDs 2 is coupled into a plate-shaped optical waveguide 3 . The light is coupled in at one or more narrow sides 4 of the plate-shaped optical waveguide 3 . The light is also radiated at one of the flat sides 5 of the plate-shaped optical waveguide 3 . The reference symbol 6 here designates the radiating direction for the direct lighting generated by the first illuminants.
The plate-shaped optical waveguide 3 is preferably produced from transparent PMMA. However, other materials are conceivable. A plate-shaped light pipe could also be used.
In contrast to the luminaires which are known from the prior art, the luminaire 1 according to the invention also has holders for second illuminants 7 . In the embodiment shown here, the second illuminants 7 are discharge lamps. However, using a different illuminant with the luminaire according to the invention is also conceivable. In the case of the luminaire 1 , the light emitted by the second illuminants 7 is radiated upward as indirect lighting. For this purpose, the luminaire 1 also has reflector arrangements 8 , which are associated with the second illuminants 7 . The reference symbol 9 designates the radiating direction for the indirect lighting which is radiated upward.
By the use according to the invention of two different illuminants 2 and 7 to generate the direct lighting 6 and indirect lighting 9 , the problem of the luminaire known in the prior art, that with only one common light source the intensity of the indirect lighting is greater than the intensity of the direct lighting, which is emitted via an optical waveguide element, can be overcome.
In the case of the luminaire 1 according to the invention, the luminous intensity of the LEDs 2 can be adjusted in such a way that the intensity of the direct lighting 6 is higher than the intensity of the indirect lighting 9 .
It is also possible, via an appropriate controller, to control the LEDs 2 and the second illuminants 7 separately from each other. In this case they can be switched on and off independently of each other, and preferably settings such as light color, color temperature or light quantity can be controlled for both illuminants 2 , 7 independently of each other.
In a preferred embodiment, LEDs 2 of different colors are used in the luminaire 1 . In this case, a desired light color of the direct lighting 6 can be controlled specially easily. Alternatively, it is of course also possible to use LEDs 2 which radiate white light.
If the indirect portion 9 of the lighting is generated using discharge lamps, an efficiency of just under 100 lm/W is achievable, with high intensity and evenness. According to the invention, the direct portion 6 of the lighting is generated using LEDs 2 . These have a maximum achievable efficiency of about 50 lm/W. Preferably, in the case of the luminaire 1 according to the invention, one or more of the techniques stated below are used to increase the efficiency of the LEDs.
Preferably, at the narrow sides 4 of the plate-shaped optical waveguide 3 into which the light of the LEDs 2 is coupled, a structure for even and specially effective coupling-in of the light is arranged. A possible structure is shown in FIGS. 2 and 3 , where the reference symbol 10 designates the stated structure.
This structure 10 here is designed so that the narrow sides 4 of the plate-shaped optical waveguide 3 , at which the light of the LEDs 2 is coupled in, are in such a form that they each form, directly in front of each LED 2 , a pyramid-shaped structure 10 with an inwardly curved peak 11 . It has turned out that if almost point-source light is coupled in, this structure 10 ensures even distribution of the light within the plate-shaped optical waveguide 3 . This structure 10 also supports the mixing of the individual light colors when LEDs 2 of different colors are used.
As shown in FIG. 1 , below the plate-shaped optical waveguide 3 a further plate 12 is arranged. On the underside of this plate 12 , an anti-glare structure 17 or diffuser is arranged, the anti-glare structure 17 only being indicated in FIG. 1 . The anti-glare structure 17 can be in the form of a micro-pyramid structure, for example. What this achieves is that glare is removed from the light which is radiated as direct lighting 6 , i.e. it is emitted only in a specified angle range. This property is important, in particular, when the luminaire 1 according to the invention is used in an office, since there are usually vertical or strongly inclined screens there, and a glare effect should be avoided.
Below the plate 12 , which has the anti-glare structure 17 or a diffuser, a further, flat, translucent plate 18 is arranged. This is a so-called closing plate 18 . Its purpose is to protect the luminaire 1 from damage and contamination.
Use of the plates 12 and 18 is an advantageous further development of the luminaire according to the invention. Dispensing with one or both plates 12 , 18 , or attaching them in an exchanged sequence, is quite conceivable. The plate 12 could also be in such a form that it generates special lighting effects, e.g. changes the light color by means of a filter.
Additionally, on the upper side of the plate-shaped optical waveguide 3 , a reflector 16 is preferably arranged. Light beams which leave the optical waveguide 3 upward are reflected back into the optical waveguide 3 by the reflector 16 , so that light is only radiated via the flat side 5 of the optical waveguide 3 .
The flat side 13 of the plate-shaped optical waveguide 3 that is not intended to radiate the direct lighting is printed with a structure 14 . As shown in FIG. 2 , it consists of longitudinal stripes. Within the plate-shaped optical waveguide, light which has once been coupled in is mostly reflected by means of total internal reflection. However, if the light meets a structure 14 which is printed on the flat side 13 , it is scattered at this structure and can emerge on the opposite flat side 5 .
This process is shown in FIG. 4 . FIG. 4 shows a cross-section through a plate-shaped optical waveguide 3 , and an LED 2 , the light of which is coupled into the optical waveguide. The light beam 15 b , which is drawn in as an example, is multiply totally reflected on the inside of the optical waveguide 3 . In contrast, the light beams 15 a strike the printed-on structure 14 on the flat side of the optical waveguide 3 and are scattered at it. Because of the scattering, these light beams 15 a now strike the flat side 5 at such a sharp angle that total reflection does not occur, but instead the beams 15 a leave the optical waveguide 3 .
The light of the LED 2 is coupled in via the narrow side 4 . Correspondingly, more light beams strike the marginal regions of the flat side 13 than the central region of the flat side 13 . To ensure even radiation nevertheless, the distance between the printed-on structure elements 14 is less in the middle of the flat side 13 .
The luminaire 1 shown in FIG. 1 is a pendant luminaire, which is fixed to a ceiling. However, the luminaire according to the invention could also be attached to a wall, at a certain distance.
FIGS. 5 and 6 show further perspective representations of the first embodiment of the luminaire 1 according to the invention.
FIG. 5 is a perspective representation of the luminaire according to the invention from below. The same reference symbols designate the same elements, which were explained in relation to the previous luminaires.
The luminaire shown in FIG. 5 has a plate-shaped optical waveguide 3 , which is composed of four optical waveguide plates 3 a , 3 b , 3 c , 3 d arranged one behind the other.
On the sides of the plate-shaped optical waveguide 3 , a luminaire carrier 12 is arranged, with at least two supporting members 13 opposite each other to support the optical waveguide 3 . Preferably, the luminaire carrier 12 and the supporting members 13 are in such a form that the LEDs 2 and the holders for the second illuminants 7 are invisible to an observer standing under the luminaire 1 . Reference symbols 6 and 9 again designate the direct lighting 6 and indirect lighting 9 respectively.
FIGS. 7 and 8 show an alternative embodiment of the luminaire according to the invention. Here the plate-shaped optical waveguide 3 is divided in the longitudinal direction by a longitudinal stay 15 . Otherwise, this luminaire agrees with the first embodiment.
FIGS. 9 and 10 show a further possible form of the luminaire according to the invention. FIG. 9 shows a plate-shaped optical waveguide 3 , LEDs 2 and a reflector 22 which is still to be discussed, seen from above. FIG. 10 also shows a cross-section through the optical waveguide shown in FIG. 9 , along the line AA.
The coupling-in structure 10 is formed here by semicylindrical recesses 21 in the narrow sides 4 of the plate-shaped optical waveguide 3 , the axis of symmetry of the corresponding cylinder being arranged perpendicularly to the flat side 5 . The LEDs 2 extend into the recesses.
Additionally, the narrow side and the marginal regions of the flat side 5 and the opposite flat side 13 are enclosed by a U-shaped reflector 22 . This U-shaped reflector 22 has, at the height of each of the LEDs 2 , a hole into which the corresponding LED 2 can be introduced.
The reflector 22 covers the marginal regions of the flat sides 5 , 13 , and correspondingly ensures that light beams which the LED 2 emits at very steep angles do not leave the plate-shaped optical waveguide at this steep angle but are reflected back into the optical waveguide.
Alternatively, the reflector 22 can be not in the form of a separate component, but instead a reflecting coating can be brought out on the narrow sides 4 and the marginal regions of the flat sides 5 , 13 of the optical waveguide. In this case, of course, it is necessary to take into account, in the same way, that immediately next to the LEDs 2 , no reflecting coating is applied, since here the light is coupled into the optical waveguide 3 .
The use of a U-shaped reflector 22 , or vapor deposition of a corresponding reflecting layer, is not only useful in the case of a coupling-in structure 10 which has semicylindrical recesses of the narrow sides 4 , but also in the case of the previously described coupling-in structure 10 , in which a pyramid-shaped structure with an inwardly curved peak 11 is formed in front of the LEDs 2 . Here too, it is necessary to take into account that the reflector 22 has recesses for the LEDs 2 , and that immediately next to the LEDs 2 , no reflecting coating is deposited.
Altogether, the luminaire 1 according to the invention is characterized by an extremely flat shape, the light which the LEDs 2 generate being radiated as direct lighting 6 over the flat side 5 of the plate-shaped optical waveguide. Additionally, according to the invention the luminaire 1 is equipped with second illuminants 7 , which radiate light in a different spatial direction as indirect lighting 9 .
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The present invention relates to a luminaire, which comprises a plate-shaped light guide, and first lamps disposed on one or more narrow sides of the light guide and configured to couple light into the plate-shaped light guide, wherein the light coupled into the light guide is emitted via a flat side of the light guide in a first irradiating direction of the luminaire. Said luminaire is characterized in that the first lamps are formed by a plurality of light-emitting diodes and that the luminaire furthermore comprises second lamps and a reflector arrangement associated therewith, by way of which the light of the second lamps is emitted in a second irradiating direction opposite the first irradiation direction.
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BACKGROUND
When electrical wire circuits are to be extended and/or connected in installation locations, where portable hand held, manipulated, and operated crimping tools are utilized to secure insulated butt splices to join two electrical wire ends, and/or to secure insulated ring tongue terminals to stripped electrical wire ends, many of these crimping tools have "T" heads used in positioning respective pairs of like sized crimping dies, at two spaced locations in the "T" head. Each location has a different size of crimping dies. Available in the past and still in the present is the completely hand and finger held, and operated portable crimping tool having a "T" head, known as an AMP "T" head crimping tool.
It is believed this "T" head arrangement of respective sets of crimping dies has not been available in a portable hand held tool that does not completely rely on hand power.
It is understood that AMP Incorporated and other companies do provide portable crimping apparatus for crimping electrical terminals onto conductors, and these portable products are selectively powered by hydraulic actuators, compressed air actuators, and/or electric motors, each requiring an external power source. However, the "T" head arrangement of the crimping dies is not known to have been incorporated into these portable products.
By way of examples, in the respective U.S. Pat. Nos. 5,309,751; No. 5,487,297; and No. 5,490,406, assigned to The Whitaker Corporation, compressed air power is utilized in respective portable crimping tools, which are operated to crimp electrical wires together, yet the "T" head arrangements is not illustrated nor described.
There remained a need to incorporate such a "T" head arrangement of crimping dies, in respective spaced pairs of different sizes in a hand held, and finger and hand manipulated, portable electrical wire crimping tool, which, after the initial placement of the members, to be crimped, undertaken by finger manipulation, could thereafter be safely operated using an external power source, when finger portions of an operator were out of the way of the continued closing movements of the crimping dies.
SUMMARY
Many portable hand held crimping tools, which are fully operated by hand and finger applied forces, have been and are being used, which have so called "T" heads presenting two sets of dies of different crimping sizes. They are used, both to secure ring tongue terminals to stripped electrical wire ends, and also, alternatively, to secure butt splices to join two electrical wires. In production periods, when these fully hand and finger operated crimping tools are extensively used, the respective operators often tire and/or fail to always complete a full and successful crimping action.
Therefore, this hand held compressed air powered crimping tool is provided to operators, who will at first use their hands and fingers to pre-position in a "T" heads, the members to be crimped. Then, after this pre-positioning is completed, an operator whose fingers cannot then re-enter the motion path of the dies, will depress and pivot the cleared trigger to open an air valve to utilize the flow of compressed air into a pneumatic actuator, which moves the crimping linkage to complete the crimping motions of the dies; and the members are then fully crimped together.
The operator is not able to move the trigger until a safety linkage, interrelated with the overall crimping linkage, has a portion thereof, i.e. a blocking member, moved out of the way of depending portions of the trigger, during the closing moments of the finger force movements of the overall crimping linkage.
Via the operation of a monitoring linkage, which is also interrelated with the overall crimping linkage, the operator is able to ascertain when the finger force movements of the overall crimping linkage are sufficiently completed to firmly hold in place the members, to be subsequently crimped together, when the compressed air power is applied to the overall crimping linkage. In addition the monitoring linkage, during the powered crimping operational period, prevents the reversal of movements of components of the overall crimping linkage. Then, when the powered crimping operational period is fully completed, and the members are successfully crimped together, the monitoring linkage then has been moved to clear the way for the reversal of motion of the overall crimping linkage. The reversal occurs under the force of a compression spring, to separate the crimping dies in the "T" head for the convenient removal of the members that are well crimped together.
During the crimping of ring tongue terminals to stripped electrical wire ends, when insulation is also crimped into position, respective insertion stops are in position in the "T" head locale to stop the insertion of the ring tongue terminals at a pre-designated location. At alternate times, when butt splices to join two electrical wires are to be crimped, the respective insertion stops are quickly and conveniently moved out of the way.
Except for the extending portions of the "T" head from a housing at one end thereof, the extending portions of a pneumatic actuator at the opposite end of the housing along with an extending compressed air supply line, and the raised hinged trigger mechanism, the balance of the components of the crimping tool, such as the various linkages, the compressed air passageways and the air valve, are all positioned within a two piece rectangular essentially hollow housing having positioners, linkage guiding groves, and openings to receive fasteners, portions of the trigger mechanism, and rotational shafts of the crimping linkage.
DRAWINGS
The hand held compressed air powered crimping tool, to secure ring tongue terminals to stripped electrical wire ends, and to secure butt splices joining together two electrical wire ends, which utilize the "IT" head arrangements of spaced sets of respective matched crimping dies of different set sizes, is illustrated in the drawings, wherein:
FIG. 1 is a perspective view of the tool ready to receive a ring tongue terminals, with an insulator, and a stripped electrical wire end in a selected set of respective matched crimping dies, of two available spaced apart sets of respective crimping dies arranged in the centrally positioned "T" head arrangement, and showing a portion of the compressed air line, and the hinged thumb or finger depressible trigger, which is in the non actionable position during the pre-positioning time of the members to be crimped, and also showing how the cylinder of the pneumatic actuator is positioned to centrally extend from the housing to serve as a handle of the tool;
FIG. 2 is a partial side view of the tool showing: the positioning of stops used in placing the ring tongue terminals in the same position for each respective crimping operation; and the hinged thumb or finger depressible trigger in the non actionable position during the pre-positioning time of the members to be crimped; and a portion of the compressed air actuator;
FIG. 3 is a partial back view of the tool showing:the stops used in placing the ring tongue terminals in their alike pre-positioning locations; the matching crimping dies in their open positions; a portion of the compressed air line; and a portion of the compressed air actuator;
FIG. 4 is a perspective exploded view of both individual parts and partially assembled parts of the hand holdable crimping tool,
FIG. 5 is view looking into the interior of the housing of the tool, after the cover has been removed, and showing the arrangement of many of the parts, before the pre-positioning of the members to be crimped, indicating that the crimping dies are in their open positions, and the blocking member of the safety linkage is covering the entries of receiving volumes, which subsequently will receive depending portions of the hinged trigger, and also showing how the overall crimping linkage is arranged in the starting position thereof before and during the propositioning of the members to be crimped;
FIG. 6 is a view, similar to the view of FIG. 5, looking into the interior of the housing of the tool, after the cover has been removed, showing, however, how the "T" head has been finger manipulated to pre-position members to be crimped, which, for illustration purposes are not shown, so the positioning of the stops is shown more clearly, and the motion arrow indicates the direction of the soon to be operated rod that extends from the pneumatic actuator into the housing and is attached to the overall crimping linkage, and, at this operational time, the blocking member of the safety linkage is not covering the entries of the receiving volumes, which soon will be receiving depending portions of the hinged trigger when the compressed air flow will be occurring;
FIG. 7 is a view, similar to the views of FIGS. 5 and 6, looking into the interior of the housing of the tool, after the cover has been removed, showing, however, the "T" head had been finger manipulated to pre-position the members to be crimped, not shown, and then the pneumatic actuator has been operated to power the overall crimping linkage to fully crimp the members together;
FIG. 8 is a view looking into the interior of the cover of the housing to illustrate: a guiding groove to guide the movement of portions of the monitoring linkage, not shown; and to show the initial positioning of two spaced rotatable pawls, having projecting portions, which changeably contact portions of the monitoring linkage, and the initial positioning of the pawls and their return to their initial positioning is controlled by the respective forces of their respective coiled springs;
FIGS. 9, 10, and 11, are similar partial enlarged views to illustrate how relative positions of the spaced rotatable pawls having the projecting portions, as shown in FIG. 8, change in relationships with cam portions of the monitoring linkage, some of which portions have ratchet teeth projections; with FIG. 9, showing their relationships at the outset of operations, when the members to be crimped are yet to be placed between the open dies; with FIG. 10 showing their relationship during the finger powered closing of the respective dies about the members to be crimped, and when the dies are so completely moved, the ratchet teeth projections maintain this completely closed position to await the start of the pressurized air power crimping operation; and with FIG. 11 showing their relationship after the completion of the pressurized air power crimping operation, when the spaced rotatable pails are then cleared away to indicate the successful full cycle of the cramping operation and to not interfere with the return of the overall crimping linkage to the starting positions thereof, to enable the release of the crimped members for their removable from between the dies, and to be reader to enable the insertion of new members between the dies for their subsequent successful crimping, and the positioning of the safety linkage, in respect to its blocking member, is illustrated, when blocking in FIG. 9, and not blocking on FIGS. 10 and 11, with respect to the movement of the trigger;
FIG. 12 is an enlarged cross sectional view, taken along section line 12--12 appealing in FIG. 5, to specifically show: how the various linkages, i.e. crimping, safety, and monitoring linkages, are interconnected; how the pneumatic actuator is connected to the crimping linkage; and the utilization of a return force compression spring;
FIG. 13 is a partial perspective view of the assembly of some of the components of the respective crimping, safety, and monitoring linkages, and their attachments to the "T" head; and
FIGS. 14 and 15 are partial sectional views to show the arrangement of the compressed air passageways, some of which are formed in housing, with arrows indicating the flow of the pressurized air form the an line, through the connection nipple, into the air valve, through a diagonal passageway in the housing, and into the cylinder of the compressed air actuator, and also indicating, when the pressurized air is shut off, the exhausting air leaves through an exhaust passageway and then through an exhaust hole in the air valve.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Introduction
The hand held compressed air powered crimping tool 20, is illustrated in a preferred embodiment in drawings. In all embodiments, this crimping tool 20 includes the well known and utilized "T" head assembly 22, which positions two spaced sets 24, 26 of dies of respective matching sizes of upper dies 28 and lower dies 30. These "T" head assemblies 22 were and are being used in hand held crimping tools that are completely manipulated by the hands and fingers of the operators. They are useful in securing members, such as ring tongue terminals 32 to stripped electrical wire ends 34 and also to secure butt splices that join together two electrical wire ends, along with their respective insulators 36.
They are used anywhere where needed, but especially in locales that are remote from shop, and working bench locations. The operators may tire during a working period in undertaking and completing all of the scheduled crimping operations. Therefore, where it is possible to have a compressed air supply source in an area where crimping operations are to be undertaken, this crimping tool 20 may be used by operators. They may conveniently hold, manipulate, and operate this crimping tool 20 with less effort while creating the better crimping of the members to complete electrical circuits and/or to complete circuit connections to electrical equipment. Very importantly, the operators, who utilize this crimping tool 20 know their fingers will not be injured by the crimping dies, when the pressurized air power is being utilized to crimp the members together.
As noted in FIG. 1, the cylindrical exterior of the cylinder 38 of the compressed air actuator 40 is extendably positioned from a hollow housing 42 to serve as a handle 44. When an operator's hand is placed about the handle 44, his or her thumb or finger is conveniently positioned to depress the pivotal trigger 46, which contacts a valve stem 48 of a compressed air valve 50 positioned in the hollow housing 42.
This pivotal trigger 46 cannot be depressed until a depending portion or portions thereof, such as depending pins 52, can enter into the hollow housing 42. Pin receiving volumes 54, 56, in the hollow housing 42, are obstructed by a blocking member 58 of a safety linkage 60, arranged in the hollow housing 42 and interconnected with the crimping linkage 62, which, is also arranged in the hollow housing 42.
After the members to be crimped, such as a ring tongue terminal 32, an insulator 36, and an electrical wire end 64, in respect to a stripped electrical wire end 34, are finger manipulated and placed between the upper and lower dies 28, 30, the "T" head assembly 22 is finger manipulated to be closed about the members to be crimped. At the conclusion of this pre-positioning of both these members to be crimped and also the "T" head, then both the crimping linkage 62, and the safety linkage 60 have been sufficiently moved by the operator's finger forces, so the blocking member 58 of the safety linkage 60, clears the pin receiving volumes 54,56, in the hollow housing 42. Thereafter the trigger 46 is pivotable to open the air valve 50 and undertake the compressed air powered crimping of the members to be crimped, and the operator has her or his fingers out of the way of the closing upper and lower dies 28, 30.
Preferably, a monitoring linkage 66, is arranged within the hollow housing 42 to serve the operator by letting her or him know the members to be crimped are fully pre-positioned, by their finger manipulations, between the dies, which are then closed so the operator will not later have his or her fingers injured, when the compressed air power is utilized during the crimping of the members. Also the monitoring linkage assembly 68 serves to keep its monitoring linkage 66, the safety linkage 60 and the crimping linkage 62, from returning to their starting open die positions of the "T" head assembly 22, until the full compressed air powered crimping cycle has been completed, thereby, insuring a successful crimping of the members has been undertaken.
The "T" Head Assembly
The "T" head assembly 22 used in this hand held compressed air powered crimping tool 20 is similar to those "T" head assemblies used in the finger and hand completely manipulated crimping tools. The "T" head assembly 22 has two "T" sections 72, 74, joined by respective fastener 70, 71, with like entries to receive other components of the "T" head, and with holes to receive a fastener to join them to a crimping actuator. The support members 76 or the leg members 76 of each "T" section 72, 74, which depend from the top portions 78 of each "T" section 72, 74, are slidably positioned in the hollow housing 42, in respect to part of their lengths.
In respective entries 80, 82, of the "T" sections 72, 74, an upper insert 84 having the spaced upper dies 28 is adjustably positioned. An adjustment cam pin 86 passes through hole 88 in "T" section 72, then through a hole 92 in the upper insert 84, and thereafter through a like hole 88 in the other "T" section 74. Upon the selected rotation of the cam pin 86 against the force of spring 85, the pointing member 87 thereof, is moved, to one of four selectable positions, indicating the simultaneously movement of, the upper dies 28, via the movement of the upper insert 84, into a selected one of four respective spaced locations from lower dies 30.
The lower dies 30 are pin 94 positioned and held in an overall entry 96 of the hollow housing 42. The lower dies 30 are arranged respective sections 98, 102, 104, and 106. The upper and lower dies 28, 30, are arranged in spaced apart sets 24, 26, and each set is of a different size. The operator then, at any one operational time has two sets of dies of respective sizes to be selected for use in crimping members together.
Two Adjustable Stops Used In Positioning Members to be Crimped In A Respective Set of Dies
The "T" head assembly 22 is preferably arranged to include two alike adjustable stops 100, one for each set of dies 24, 26. Each stop 100 has a depending elongated pin receiving entry 101. Pins 94 used in positioning the lower dies 30 in the overall entry 96 of the hollow housing 42, also are passed through the depending elongated receiving entries 101, to adjustably hold these stops 100 in their respective alternate positions.
In their in use position, a member to be crimped, such as the ring tongue terminal 32, is moved to contact an adjustable stop 100, in the same way pre-positioning of all the members to be crimped. In their non use position, each adjustable stop 100 is moved clear of the members to be crimped, via the clearance provided in the depending elongated receiving entry 101.
The Housing of the Hand Held Crimping Tool
The hollow housing 42 is preferably rectangular in its overall configuration and made in two pieces 108, 110. One piece 108 is made to have a larger receiving volume 112 to receive and to position the components of the crimping linkage 62, the safety linkage 60, and the monitoring linkage assembly 68. Also partially positioned within this larger receiving volume 112 are portions of the "T" head, and portions of the compressed air, i.e. pneumatic, actuator 40. In addition clearance volumes 114, not specifically formed, receive, at selected compressed air power operational times, the depending pins 52 of trigger 46, which pass through respective holes 116 in this housing piece 108.
The larger receiving volume 112 piece 108 of the hollow housing 42 includes a groove 118 to slidably receive and guide portions of the crimping linkage 62 and the safety linkage 60. Also this piece 108 includes a threaded entry 122 for securing the pneumatic actuator 40. In addition an opening 124 is provided for an air nipple connector 126, for connection to an airline 127 an opening 128 for an air valve 50, two openings 132 to receive mounting pins 134 to pivotally position left and right pivotal lever arms 136, 138, of the crimping linkage 62, and openings 142 to receive fasteners 144 that hold the pieces 108, 110, of the hollow housing together. Also during the assembly of this crimping tool 20 and the hollow housing 42, thereof, close fitting positioning pins 140 are arranged through positioning holes 141. The piece 108 of the hollow housing 42 also has internal compressed air passageways 146 to direct compressed air from the air nipple connector 126 to the air valve 50, then to the compressed air, i.e. pneumatic actuator 40.
The Crimping Linkage
The crimping linkage 62, is connected between the "T" head assembly 22 and the compressed air, i.e. pneumatic, actuator 40 and operationally mounted within the hollow housing 42. In FIGS. 5 and 6, the crimping linkage 62 is illustrated in the starting positions. During this starting time the members to be crimped together and being positioned between a set 24 or 26 of the dies, and the "T" head assembly is initially moved by finger applied force to move dies into firm contact with the members to be crimped. Under their finger applied force, the crimping linkage 62 in part, moves a distance, to also move the safety linkage 60, so the blocking member 58 clears away from the path of the depending pins 52 of the trigger 46.
Then, when the operator's fingers are well clear of the sets of dies 24, 26, the operator depresses the trigger 46, operating the valve 50, and compressed air enters and moves the compressed air, i.e. pneumatic, actuator 40, which inturn completes the movements of the crimping linkage 62, into the overall position shown in FIG. 7.
The several components of the crimping linkage 62 are also illustrated in FIGS. 4 and 13, and in respect to these several components, they are:
a) two spaced apart links 148, 152, as shown in FIG. 13, with respective spaced sets of aligned holes 154, 156;
b) a positioning pin 158 passed through the aligned holes 154 and through aligned holes 162 of the support members 76 of the "T" sections 72, 74, of the "T" head assembly 22, to thereby join the crimping linkage 62 to the "T" head assembly 22;
c) another positioning pin 164 passed through the aligned holes 156 and through the center of a roller bearing 166;
d) respective left and right pivotal lever arms 136, 138, each having respective offset pawls 174, 176, at one of their ends to movably contact the roller bearing 166, and each having at their other ends pin 178 mounted roller 182, and each being rotatably secured, with pins 134, between their ends to the hollow housing 42, in piece 108 thereof; and
e) a moveable spreader 186 guided between the left and right pivotal arms 136, 138, utilizing the rollers 182, and connected to the pneumatic actuator 40.
This arrangement of the crimping linkage 62, when moved by the compressed air force, via the pneumatic actuator 40, creates a better and stronger crimping force applied, via the offset pawls 174, 176, of the left and right pivotal arms 136, 138, secured to the spaced apart links 148, 152, inturn secured to the "T" head assembly 22.
The Pneumatic Actuator, i.e. The Compressed Air Actuator
The pneumatic actuator 40, also referred to as the compressed air actuator 40, has an end 188 with threads 192 and an "O" ring 194 for threadably securing and sealing the end 188 in the threaded entry 122 of the hollow housing 42. The remaining portions of the pneumatic actuator 40, being cylindrical in shape, serve as the handle 44 of the crimping tool 20. A rod 190 extending from a piston, not shown, of the pneumatic actuator 40, movably extends into hollow housing 42 and is threadably attached to the movable spreader 186 of the crimping linkage 62.
The Compressed Air Guiding and Controlling Arrangement
The compressed air guiding and controlling arrangement 196 is illustrated in FIGS. 14 and 15. This arrangement 196 has:
a) a connector nipple 126 mounted in an entry 124 of the hollow housing 42 for connection to a compressed air supply line 127;
b) passageways 146 formed in the hollow housing 42, and specifically formed in piece 108 thereof, to guide the flow of entering compressed air, and subsequently in part to guide the flow of exhausting air. These passageways 146 direct the compressed air from the connection nipple 126 to the valve opening 128, serving as a valve chamber 204, into the air valve 50, and on to the cylinder 38, via orifices 208, thereof;
c) the cylinder 38, and piston, not shown, of the pneumatic actuator 40; and
d) the valve 50 and the valve stem 48 thereof, having an exhaust orifice 212, with the valve stem 48 projecting out of the hollow housing 42 to be depressibly contacted by the trigger 46.
The Finger Depressible Trigger
The finger depressible trigger 46 is pivotally secured to piece 108 of the hollow housing 42, by a hinge arrangement 214. Two depending pins 52 are attached to the finger contacting portion 216 of the trigger 46. They are arranged to pass through respective entries 116 and into the pin receiving volumes 54, 56, in the hollow housing 42, when a blocking member 58 of a safety linkage 60 has been moved clear of the entries 116 of the pin receiving volumes 54, 56.
The Safety Linkage
The safety linkage 60 and its effective use is illustrated in FIGS. 1, 4, 5, 6, 7, 9, 10, 11, and 13. The safety linkage 60 is interconnected with the crimping linkage 62, by in effect being an integral extension 222 of link 152 of the two spaced apart links 148, 152, of the crimping linkage 62, as particularly shown in FIG. 13.
In FIGS. 1, 3, 5, and 9, the "T" head assembly 22 is illustrated when the sets 24, 26, of the crimping dies are spaced apart awaiting the entry of the members to be crimped. At the time the safety linkage 60 along with the crimping linkage 62 have been moved back to their starting positions by the force of the return coiled spring 222 as shown in FIG. 12.
When the members to be crimped are being positioned between a selected set 24 or 26 of dies, as indicated in FIG. 1, then as shown in FIGS. 5 and 9, a blocking member 58 of the safety linkage 60 is obstructing the entries 218 in the hollow housing 42, preventing the depending pins 52 of the trigger 46 from entering receiving volumes 54, 56, in the hollow housing 42. At this time the operator of this hand held crimping tool 20 is using his or her fingers, both to position the members to be crimped and also to move the set 24 or 26 of the dies together to preliminary bear against the members to be crimped, as shown in FIG. 10. At the last moments of this finger manipulation, the crimping linkage 62 and the safety linkage 60 have moved sufficiently, so the blocking member 58 clears the entries 218 in the hollow housing 42, as illustrated in FIG. 10.
Also at this time the operator has cleared his or her fingers from around the dies, and then he or she adjust his or her hand and fingers to enable the subsequent depressing of the trigger 46. In FIG. 11, the members initially to be crimped, are then shown to have been crimped, after the trigger has been actuated, resulting in the utilization of the compressed air power to complete their crimping.
The Monitoring Linkage Assembly
Preferably a monitoring linkage assembly 68, inclusive of a monitoring linkage 66, is utilized in respect to three functions. First, this assembly 68 is used to monitor the adequate finger forced moment of a set 24 or 26 of the dies about members to be crimped to keep them in their intended pre-positioning arrangement, while awaiting the utilization of the compressed air power. Second, this assembly 68 is used to monitor the adequate completion of the crimping of the members during the utilization of the compressed air power. Third, this assembly 68 is then used to clear the way for the crimping linkage 62, the safety linkage 60, and its own monitoring linkage 66, to be returned to their starting positions, via the return force of the coiled spring 222.
As shown in FIG. 12, the coiled spring 222, is confined and guided by the movable spreader 186. Also the coiled spring 222 extends between the end 188 of the rod 190 of the compressed air actuator 40, and the capped extending rod 218 having the cap 220, which directly contacts the coiled spring 222. The other end of the capped extending rod 218 directly contacts the roller bearings 116.
The monitoring linkage assembly 68 is illustrated in part in FIGS. 8 and 13, and then as assembled and utilized in FIGS. 9, 10, and 11. In FIG. 8, the hollow interior 224 of piece 110, serving as a cover 110, of the hollow housing 42 is shown as having a recess portion 226 serving to guide a portion of the monitoring linkage 66 and to position other components of the monitoring linkage assembly 68. In FIG. 13, the assembly of some of the crimping linkage 62 components, the safety linkage 60, and some of the components of the monitoring linkage assembly 68, is illustrated.
Of the two spaced apart links 148, 152, of the crimping linkage 62, the link 148 is integrally extended creating an extension 228, and further formed to have respective opposite side located alike functioning cams 232. Each cam 232 has two sets of clearances 234, 236, and a set of opposite extending portions 238 with ratchet teeth 242 on one side located axially at a slightly different location, i.e. offset location, than the ratchet teeth 242 on other side. This positioning creates more ratcheting positions, when the members to be crimped, are being firmly gripped in a set 24, or 26 of the dies, so they will remain in position, awaiting the crimping under the force derived from utilizing compressed air.
When this extension 228, serving as a part of this monitor linkage assembly is positioned in the recess portion 226 of the cover 110, the cams 232 thereof are operationally interfitted with additional components of this assembly 68, which are particularly shown in FIG. 8. They are the spaced pivotal pawls 244 rotatably mounted on the hollow housing 42 and having extending portions 246, which are able to movably contact the cams 232 and the ratchet teeth 242 thereof to create the monitoring effect during the finger applied forces used, when the members to be crimped are being positioned in the set 24 or 26 of the dies.
Respective coiled springs 248, secured to the hollow housing 42 and interfitted between their securement locations 252 and the spaced pivotal pawls 244, serve:
a) to keep the pawls 244 in their starting positions at the outset of a crimping operation
b) to keep the pawls 244 in contact with the ratchet teeth 242 during the prepositioning of the members to be crimped; and
c) after the powered crimping of the members, to clear the pawls 244 as all the linkages return to their starting positions.
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A hand held compressed air powered crimping tool is used both to secure ring tongue terminals to stripped electrical wire ends, and to secure butt splices that join together two electrical wire ends. The dies used, their locations, their retention, and their movements are similar to existing "T" head crimping tools, which are finger and hand manipulated and powered. When using this compressed air powered tool, pre-positioning is still undertaken by fingers and hands, of wires, ring tongue terminals or the butt sleeves, and insulation covers, to be crimped. Continued finger and hand movements, move together respective "T" head portions to preliminary keep together all the members to be crimped, in their respective positions. At the conclusion of the preliminary positioning, no spaces are left around dies for any unwanted entry of finger portions of the operator. At the last moment of the preliminary positioning, a blocking member of a safety linkage is cleared away from respective receiving volumes, permitting the subsequent entry of respective depending safety portions of a finger actuated hinged lever trigger. The trigger, when intentionally moved, depresses an upstanding air valve stem to open the air valve for the flow of compressed air to the pneumatic actuator that completes the movements of the overall crimping linkage. Preferably, a monitoring linkage is moved during the preliminary positioning, to insure the members to be crimped are securely held, until the compressed air power is subsequently utilized. The monitoring linkage must complete its travel during the powered fall crimping action directional sequence period, before it reverses its travel direction to clear the way for a release opposite directional movement of the crimping linkage undertaken, when compressed air power is off, and a return force is provided by a compression spring.
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[0001] This patent application is a division of application Ser. No. 09/857,768, filed Jun. 11, 2002, which is the National Phase of International Application PCT/US99/29987 filed Dec. 17, 1999, which claims priority from U.S. Provisional Application No. 60/113,064, filed Dec. 21, 1998. The contents of these applications are hereby incorporated into the present application by reference in full.
FIELD OF THE INVENTION
[0002] The present invention relates to vacuum forming or pressure forming articles and apparatuses, and, more particularly, a molding method combining vacuum and pressure for producing reinforced thermoplastic articles. The invention also relates to molded articles having reinforced foam fillers.
BACKGROUND OF THE INVENTION
[0003] Traditional blow molding is limited as to the wall thickness of the article to be formed, as well as the complexity of article shape. To overcome this, thermoforming, a modification of blow molding, can suffice for manufacturing articles having relatively thick walls and/or complex shapes. Thermoforming processes such as plug assisted vacuum forming or pressure forming permit the production of items having a wall thickness of up to about ⅜ inch (95.25 mm). Articles formed by conventional blow molding, by contrast, are usually limited to wall thicknesses of less than about ⅛ inch (31.75 mm). This is due, in part, to the negative effects exerted on the blowing process by the greater volumes of polymer resin required to achieve thicker walls. For example, increasing amounts of viscous molten polymer will limit the size, wall thickness and complexity of an article to be formed, as blown air becomes progressively ineffective at expanding molten polymer as the volume of polymer material increases.
[0004] In basic vacuum forming, a carrier frame delivers a heated plastic sheet to a mold assembly, after which the sheet is clamped and sealed against the mold edge surfaces. Application of a vacuum causes atmospheric pressure to force the sheet against the mold cavity to assume the cavity shape. Mold cooling promotes the formation of a thin sheet having the dimensions defined by the mold.
[0005] As a variation of blow molding, the above-mentioned process further includes the step of blowing air of controlled pressure to force the heated sheet away from the cavity into a bubble. A shaped plug is then inserted into the bubble, pressing the bubble back into the mold cavity after the sheet has been sealed across the mold cavity. Upon reaching the bottom of the mold cavity, compressed air and/or a vacuum is applied to force the sheet against the mold. After forcing the sheet into the cavity, a full vacuum is applied from the cavity side and positive pressure is applied from the plug side of the apparatus to complete the formation of a molded article. After it has solidified, the mold assembly is opened, and the article is removed.
[0006] In a similar fashion, drape forming entails either draping a plastic sheet over or moving a male mold into a plastic sheet, and thereafter clamping, heating, and sealing the sheet over the male mold. Numerous vent holes in the mold apparatus permit a vacuum to be drawn, allowing atmospheric pressure to force the draped sheet into the contours of the mold cavity. Upon cooling, the sheet shrinks onto the mold.
[0007] Typical vacuum-formed or pressure-formed products include blister and skin packaging, food and drink containers, toys, luggage, and auto and appliance parts. Polystyrene, polypropylene, HDPE, thermoplastic polyester, ABS and vinyls are often used to manufacture these articles. Films and sheets formed in this fashion are often laminated by melt or adhesive processes to enhance their functional performance.
[0008] A need has arisen for reinforced blow molded articles having good thermoinsulating and sound barrier properties. In particular, the resurgence in popularity of removable hard tops and T-tops for automobiles has prompted engineers to seek better insulating characteristics of blow molded articles. For example, lightweight, suitably thermoinsulated removable hard tops for sport utility vehicles (SUVs) are in high demand by consumers. While blow molding provides for sufficiently lightweight automobile parts, combining the suitable weight properties with good impact resistance and thermoinsulating properties has heretofore been difficult.
[0009] The usefulness of blow molding techniques for forming such impact resistant, thermoinsulated articles has not been practical due to the structural characteristics of the plastic material conventionally used in blow molding. That is, the ability to blow mold light weight, thermoinsulated parts is limited by the fact that the parts produced can be only so large or so thin before the parts lose their structural integrity and impact resistance.
[0010] Further, most insulating materials must be laminated to the part after blow molding into the desired shaped. For example, urethane foam may be introduced to a blow molded part to improve insulating capabilities, as well as dimensional stability. However, this process is plagued by incompatibility between the skin component of the molded part and the insulating foam filler. Expensive thermoplastic skins are often chemically incompatible with traditional foam insulating materials, preventing strong bond formation within laminated structures. Thus, blow molded articles having skin and foam fillers of different materials are prone to delamination. A solution to the delamination problem is to fill the article with a foamed resin identical to the resin used to form the exterior skin of the article. Although this expensive concept is acceptable for many blown articles, it is insufficient for producing a cost effective automobile part having good impact resistance.
[0011] Blow molded articles such as sport utility vehicle (SUV) hard tops require good thermoinsulation while exhibiting strong impact resistance. By nature, structural foams lack good impact resistance due to their open cellular conformation. Thus, blow molded automobile parts having structural foam insulating materials compatible with an exterior resin skin require reinforcement.
[0012] Heretofore, in order to reinforce various plastic parts, such parts would conventionally comprise resins fortified by mineral fillers or glass fibers. However, such reinforcement cannot be used effectively in blow molding operations, because the glass fibers limit parison expansion characteristics and also have a deleterious effect on the blow molding assembly itself. Furthermore, such reinforcement has a deteriorating effect on the foaming capabilities of resins. Thus, blow molded articles having a structural foam component subjected to conventional reinforcement often lack uniform strength and impact resistance.
[0013] Similarly, thermoformed articles having foam backing typically lack satisfactory levels of impact resistance due to both the need for an aesthetically pleasing skin and the open cellular nature of reticulated foam. Exterior skin appearance deteriorates with increasing amounts of conventional reinforcing materials. Typical reinforcing materials tend to impair the formation of reticulated cells during blowing of foam resins. Because structural foams are not adequately reinforced by conventional means, thermoformed articles comprising good quality skins laminated to foam backing have inadequate strength and impact resistance.
SUMMARY OF THE INVENTION
[0014] It is an object of the present invention to overcome the problems noted hereinabove. In achieving this object, the present invention provides a method for thermoforming reinforced, insulated thermoplastic parts. Accordingly, the present invention provides a method for molding articles, comprising the steps of providing a first reinforced plastic sheet comprising at least one thermoplastic material and reinforcement nanoparticles dispersed within the at least one thermoplastic material. The reinforcement particles comprising less than 15% of a total volume of the plastic sheet, and at least 50% of the reinforcement particles having a thickness of less than about 20 layers, and at least 99% of the reinforcement particles having a thickness of less than about 30 layers. The heated plastic sheet is communicated to a first mold assembly having a first mold cavity defined by mold surfaces. The mold surfaces correspond to a configuration of the article to be molded. An amount of the plastic sheet is communicated to the first mold assembly being sufficient to form a skin of the article. A vacuum is applied to one side of the first mold assembly while concurrently applying pressurized gas to an opposing side of the first mold assembly so as to force the heated plastic sheet into conformity with the mold surfaces. The conformed plastic sheet is then cooled. The conformed plastic sheet is then transferred to a second mold assembly. A reinforced plastic melt made from material identical or different from that of the plastic sheet is introduced to the conformed plastic sheet. The plastic melt has a blowing agent to achieve volume expansion and the production of a cellular reticulate structure. The plastic melt is then cooled to form a solidified plastic member adhered to the conformed plastic sheet. The conformed plastic sheet and the adhered solidified plastic member together comprise the article. The article is removed from the second mold assembly.
[0015] It is also an object of the invention to produce reinforced parts for automotive applications via plug assisted thermoforming, which has heretofore been impractical.
[0016] An embodiment of the invention is a child safety seat having a reinforced outer skin member and a reinforced foamed structural member. The seat members are formed from at least one thermoplastic material and reinforcement nanoparticles dispersed within the at least one thermoplastic material. The reinforcement particles comprise about 2% to about 15% of a total volume of the molded hard top, at least 50% of the reinforcement particles have a thickness of less than about 20 layers, and at least 99% of the reinforcement particles have a thickness of less than about 30 layers.
[0017] In another embodiment, a substantially hollow molded hard top for an automobile which is filled with foamed insulating material is formed from at least one thermoplastic material and reinforcement nanoparticles dispersed within the at least one thermoplastic material. The reinforcement particles comprise about 2% to about 15% of a total volume of the molded hard top, at least 50% of the reinforcement particles have a thickness of less than about 20 layers, and at least 99% of the reinforcement particles have a thickness of less than about 30 layers.
[0018] Other objects and advantages of the present invention will become apparent from the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] A preferred embodiment of the present invention is described herein with reference to the drawing wherein:
[0020] [0020]FIG. 1 shows a perspective view of a sport utility vehicle hardtop contemplated by the invention, and
[0021] [0021]FIG. 2 shows a sectional view of the top depicted in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] It is contemplated that reinforced skins according to the invention may be prepared using any conventional pressure forming method. Preferably, the mold assembly is provided with appropriate water cooling lines and a temperature control unit in conventional fashion for regulating the temperature of the mold assembly. The molds may assume a complex or detailed shape, providing for reinforced complex shapes having a reinforced foam core produced according to the invention.
[0023] In accordance with the present invention, the plastic melt (and thus the resultant part) comprises at least one thermoplastic material and reinforcement particles dispersed within the at least one thermoplastic material. The reinforcement particles about 2% to about 15% of a total volume of the plastic melt, at least 50% of the reinforcement particles have a thickness of less than about 20 layers, and at least 99% of the reinforcement particles have a thickness of less than about 30 layers. The reinforcement filler particles, also referred to as “nanoparticles” due to the magnitude of their dimensions, each comprise one or more generally flat platelets. Each platelet has a thickness of between 0.7-1.2 nanometers. Generally, the average platelet thickness is approximately 1 nanometer thick. The aspect ratio for each particle, which is the largest dimension divided by the thickness, is about 50 to about 300.
[0024] The platelet particles or nanoparticles are derivable from larger layered mineral particles. Any layered mineral capable of being intercalated may be employed in the present invention. Layered silicate minerals are preferred. The layered silicate minerals that may be employed include natural and artificial minerals. Non-limiting examples of more preferred minerals include montmorillonite, vermiculite, hectorite, saponite, hydrotalcites, kanemite, sodium octosilicate, magadiite, and kenyaite. Mixed Mg and Al hydroxides may also be used. Among the most preferred minerals is montmorillonite.
[0025] To exfoliate the larger mineral particles into their constituent layers, different methods may be employed. For example, swellable layered minerals, such as montmorillonite and saponite are known to intercalate water to expand the inter layer distance of the layered mineral, thereby facilitating exfoliation and dispersion of the layers uniformly in water. Dispersion of layers in water is aided by mixing with high shear. The mineral particles may also be exfoliated by a shearing process in which the mineral particles are impregnated with water, then frozen, and then dried. The freeze dried particles are then mixed into molten polymeric material and subjected to a high sheer mixing operation so as to peel individual platelets from multi-platelet particles and thereby reduce the particle sizes to the desired range.
[0026] The extruded plastic sheet utilized in accordance with the present invention is prepared by combining the platelet mineral with the desired polymer in the desired ratios. The components can be blended by general techniques known to those skilled in the art. For example, the components can be blended and then melted in mixers or extruders. Preferably, the plastic melt is first manufactured into pellet form. The pellets are then plasticized in the extruder to form a plastic melt, which exits the extruder in sheet form.
[0027] Additional specific preferred methods, for the purposes of the present invention, for forming a polymer composite having dispersed therein exfoliated layered particles are disclosed in U.S. Pat. Nos. 5,717,000, 5,747,560, 5,698,624, and WO 93/11190, each of which is hereby incorporated by reference. For additional background, the following are also incorporated by reference: U.S. Pat. Nos. 4,739,007 and 5,652,284.
[0028] Preferably, the thermoplastic used for the purposes of the present invention is a polyolefin or a blend of polyolefins. The preferred polyolefin is at least one member selected from the group consisting of polypropylene, ethylene-propylene copolymers, thermoplastic olefins (TPOs), and thermoplastic polyolefin elastomers (TPEs).
[0029] The exfoliation of layered mineral particles into constituent layers need not be complete in order to achieve the objects of the present invention. The present invention contemplates that at least 50% of the particles should be less than about 20 nanometers in thickness and, thus, at least 50% of the particles should be less than about 20 layers thick. In addition, at least 99% of the reinforcement particles should have a thickness of less than about 30 nanometers, which is about 30 layers stacked in the thickness direction. With this extent of exfoliation, with a loading of less than 15% by volume, the benefits of the nanoparticles begin to accrue with meaningful effect for many large thin part applications. For example, such loading of nanoparticles will provide a desired increase in the modulus of elasticity by about 50-70% over conventional fillers. Preferably, about 2% to about 15%, even more preferably about 2% to about 8% loading in used to achieve desirable reinforcement.
[0030] More preferably, at least 50% of the particles should have a thickness of less than 10 nanometers. At this level, an additional increase of about 50-70% in the modulus of elasticity is achieved in comparison with the 50% of particles being less than 20 layers thick as discussed above. This provides a level of reinforcement and impact resistance that would be highly suitable for most motor vehicle part applications, such as reinforced insulated hard tops.
[0031] Preferably, at least 70% of the particles should have a thickness of less than 5 layers, which would achieve an additional 50-70% increase in the modulus of elasticity in comparison with the 50% of less than 10 layer thickness exfoliation discussed above. This provides ideal reinforcement and impact resistance for large thin parts that must withstand substantial impact. It is always preferable for at least 99% of the particles to have a thickness of less than about 30 layers, as particles greater than this size act as stress concentrators.
[0032] It is most preferable to have as many particles as possible to be as small as possible, ideally including only a single platelet.
[0033] As noted above, the preferred aspect ratio (which is the largest dimension divided by the thickness) for each particle is about 50 to about 300. At least 80% of the particles should be within this range. If too many particles have an aspect ratio above 300, the material becomes too viscous for forming parts in an effective and efficient manner. If too many particles have an aspect ratio of smaller than 50, the particle reinforcements will not provide the desired reinforcement characteristics. More preferably, the aspect ratio for each particle is between 100-200. Most preferably, at least 90% of the particles have an aspect ratio within the 100-200 range.
[0034] Generally, in accordance with the present invention, the plastic melt and hence the parts to be manufactured should contain less than 15% by volume of the reinforcement particles of the type contemplated herein. The balance of the part is to comprise an appropriate thermoplastic material and suitable additives. If greater than 15% by volume of reinforcement filler is used, the viscosity of the composition becomes too high and thus difficult to mold.
[0035] By utilizing plastic melt with the loading of nanoparticles discussed above (e.g., less than 15% of a total volume of the plastic melt), higher modulus of elasticity of conventional large plastic parts can be achieved, and thus be manufactured with a reduced wall thickness while maintaining the same required impact resistance. For example, the modulus of the material used to form an article may be increased to between about 200,000 to about 500,000 PSI (1378-34.46 MPa).
[0036] In accordance with the present invention, addition of the exfoliated platelet material as set forth above permits the modulus of vacuum formed articles to be increased without significantly losing impact resistance. Because the modulus is increased, large parts, such as removable automobile hard tops, can be made thinner than what was otherwise possible. Such parts may also be insulated by reinforced foam, thereby adding sound proofing and thermal insulation to thinner hard tops without jeopardizing impact resistance. More specifically, hard tops for automobiles must have sufficient impact resistance or toughness to withstand various standard automotive impact tests, particularly roll over tests.
[0037] For example, an automotive hard top must withstand a typical impact test wherein the hard top will not crack or permanently deform upon impact. In a conventional IZOD impact test, it is desirable for the part to withstand at least 10-ft pounds/inch (535 J/m) at room temperature and at least 5-ft pounds/inch (263 J/m) at −30° C. In order to withstand cracking at such force levels, the modulus of a conventional automotive material is typically between about 70,000 to about 150,000 pounds per square inch (PSI) (482-1034 MPa). In accordance with the present invention, the hard top modulus can be increased by a factor of 2 to 3 times, without significantly effecting the impact resistance.
[0038] In addition to the above mentioned benefits, use of the nanoparticle reinforced plastic melt enables the coefficient of linear thermal expansion to be reduced to less than 40×10 −6 inches of expansion per inch of material per degree Fahrenheit (IN/IN)/° F., or 72×10 −6 mM/mm/°C., which is less than 60% of what was previously achievable for thermoplastic motor vehicle parts that meet the required impact tests.
[0039] As a further benefit, the surface toughness of the hard top can be improved. The improved surface toughness provided by the nanoparticles greatly reduces handling damage and part scrap. This is a significant benefit to a part which by design is repeatedly removed from an automobile and must endure unexpected scraping, dropping and non-collision impact.
[0040] In addition, it is possible to more than double the modulus of polymers without significantly reducing toughness. Thus, it is possible to produce articles like hard tops using 20-35% thinner wall sections that will have comparable performance. The use of nanoparticles can provide the mechanical, thermal, and dimensional property enhancements, which are typically., obtained by adding 20-50% by weight of glass fibers or mineral fillers or combinations thereof to polymers. However, only a few percent of nanoparticles are required to obtain these property enhancements.
[0041] As a result of the fact that such low levels of nanoparticles are required to obtain the requisite mechanical properties, many of the typical negative effects of the high loadings of conventional reinforcements and fillers are avoided or significantly reduced. These advantages include: lower specific gravity for a given level of performance, better surface appearance, toughness close to that of the unreinforced base polymer, and reduced anisotropy in the molded parts.
[0042] It is preferable for these articles to have reinforcement particles of the type described herein comprising about 2% to about 8% of the total volume of the article, with the balance comprising the thermoplastic substrate. It is even more preferable for removable hard tops to have reinforcement particles of the type contemplated herein comprising about 3%-5% of the total volume of the part.
[0043] In accordance with another specific embodiment of the present invention, it is contemplated that the blow molding apparatus can be used to make relatively large, highly reinforced parts having a modulus of elasticity of 1,000,000 (6892 MPa) or greater. Conventionally, these parts typically require loadings of 25-60% by volume of glass fiber reinforcement. This amount of glass fiber loading would result in a high viscosity of any melt pool that could be used in the blow molding apparatus of the present invention and would thus render the blow molding apparatus largely impractical for such application.
[0044] Sheets of the plastic melt described above enable the plug assisted thermoforming of large parts having impact resistance characteristics previously unattainable. For example, the thermoforming system of the present invention is able to manufacture relatively large articles having a modulus of elasticity of greater than 1,000,000 PSI (6892 MPa) by use of a plastic melt reinforced with loadings of about 8-15% by volume of nanoparticles, with at least 70% of the nanoparticles having a thickness of 10 layers or less. As with the above described embodiment, the plastic melt used has substantially the same material composition as the article to be manufactured.
[0045] In this case of molding large parts with a modulus of elasticity greater than 1,000,000 PSI (6892 MPa), it may be desirable to use engineering resins instead of polyolefins. Such engineering resins may include polycarbonate (PC), acrylonitrile butadiene styrene (ABS), a PC/ABS blend, polyethylene terephthalates (PET), polybutylene terephthalates (PBT), polyphenylene oxide (PPO), or the like. Generally, these materials in an unreinforced state have a modulus of elasticity of about 300,000 PSI -350,000 PSI (2068-2412 MPa). At these higher loadings of nanoparticles (8-15% by volume), impact resistance will be decreased, but to a much lower extent than by the addition of the conventional 25-60% by volume of glass fibers.
[0046] The invention may be used to reinforce any item ordinarily produced by thermoforming. For example, removable automobile hard tops depicted in FIGS. 1 and 2, produced by plug assisted thermoforming may be reinforced, using the inventive reinforcing particles. Such thermoformed hard tops further comprising structural foams having reinforcing nanoparticles exhibit better impact resistance, thermoinsulation and sound insulation than conventionally produced removable automobile hard tops.
[0047] Reinforced child safety seats may also be manufactured according to the invention. Reinforcing nanoparticles of the invention can strengthen the thermoformed shell of the seat as well as the foam cushioning within the seat. Child seats reinforced with nanoparticles have better ductility for impact energy absorption than seats having standard reinforcing materials. The increased strength and impact resistance of such safety seats affords better protection for seat occupants.
[0048] Reinforced articles having relatively thick walls may be produced according to the invention when the reinforced article comprises a thermoformed skin blown from a reinforced polymer sheet under vacuum using plug assistance. Larger, thicker, more complex articles may be formed according to the invention than is possible by blow molding unreinforced polymers or polymers reinforced by, for example, glass fibers. This is because the reinforcing particles of the invention may be evenly dispersed in molten resin, do not clump, and avoid generating stress points likely to induce tears in the melted polymer during the blowing/forming step.
[0049] Although certain embodiments of the invention have been described and illustrated herein, it will be readily apparent to those of ordinary skill in the art that a number of modifications and substitutions can be made to the blow molding system disclosed and described herein without departing from the true spirit and scope of the invention.
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A hollow, reinforced, molded automotive hard top is made using a sheet of thermoplastic material with nanoparticles dispersed therein. The particles comprise less than 15% of total volume of the plastic sheet, at least 50% of the particles have a thickness less than about 20 layers, and at least 99% of the particles have a thickness of less than about 30 layers. The sheet is preheated and molded in an assembly having mold surfaces corresponding to the hard top configuration. Vacuum is applied to one side of the assembly and pressurized gas is applied to the opposite side of the assembly to force the sheet into conformity with the mold surfaces. After cooling, the conformed sheet is transferred to another mold assembly, where a reinforced plastic melt having a blowing agent is applied. Together, the solidified melt and the conformed plastic sheet form the hard top.
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[0001] This application claims the benefit of the Korean Patent Application Nos. 10-2005-0057968 and 10-2005-0057970 filed on Jun. 30, 2005, which are hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a washing machine, and more particularly, to a method for controlling a course in a washing machine so as to improve the efficiency in decomposition of protein and anti-bacteria effect.
[0004] 2. Discussion of the Related Art
[0005] Generally, a washing machine is one of widely used electric home appliances. The washing machine is an apparatus for removing contaminants from the laundry such as clothes by an emulsification of detergent, a friction of a washing water motion generated by a drum rotation, and an impact applied to the laundry.
[0006] The generally used washing machine is largely classified into a pulsator type, an agitator type, and a drum type. Based on whether a washing tub is separated from a spin-drying tub or not, the washing machine may be divided into a separation type and an automatic type.
[0007] In general, a washing operation is performed in a course of supplying the detergent and the washing water to the laundry to be washed such that contaminants can be removed from the laundry by a chemical action of the detergent contained in the washing water and a physical action of a blade of the washing machine.
[0008] Then, a rinsing operation is performed in a course of supplying washing water containing no detergent therein such that the detergent and contaminants can be rinsed out of the laundry. A spin-drying operation is performed in a course of rotating the washing tub at a high speed after completing the rinsing operation such that moisture can be removed from the laundry.
[0009] In the general washing machine, a user can selectively set the washing conditions relating operation time periods of washing, rinsing, and spin-drying according to the kind and amount of laundry.
[0010] For convenience of the user, the washing machine has a memory in which various course programs for an automatic washing process are previously stored. Accordingly, the user can select the corresponding course program from the various programs previously stored in the memory according to the kind and amount of laundry to be washed.
[0011] That is, the various course programs, for example, a centrifugal washing course, a high-consistency washing course, a pre-washing course, a vibration course, a soaking-type washing course, and a wool-laundry washing course, are previously stored in the memory of the washing machine. Accordingly, the user selects the desired course program in the washing machine, and performs the automatic washing stroke according to the desired course program.
[0012] However, even though the various course programs are provided in the washing machine, the long-time used clothes may be discolored or yellowed due to the contaminants of protein components and the limitation in chemical action of the detergent.
[0013] To remove the contaminants of protein components from the laundry, it is necessary to increase a mechanical power applied to the laundry by generating a strong rotary power with the blade or spin-drying tub. In this case, the laundry may be damaged or entangled due to the strong rotary power.
[0014] Also, the related art washing machine performs the washing stroke with the cold water or warm water of low temperature. Thus, it is difficult to destroy the bacilli of the laundry with the related art washing machine using the cold or warm water. Especially, if the bacilli are left in the washed laundry, the bacilli may damage the user's skin health, and the user may feel displeased and uncomfortable.
SUMMARY OF THE INVENTION
[0015] Accordingly, the present invention is directed to a method for controlling a course of a washing machine that substantially obviates one or more problems due to limitations and disadvantages of the related art.
[0016] An object of the present invention is to provide a method for controlling a course of a washing machine to remove bacilli as well as protein contaminants from a washing tub and the laundry.
[0017] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0018] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a method for controlling a course of a washing machine comprises (a) selecting an anti-yellow course of a washing stroke, so as to set washing conditions which is suitable for activating deposition of protein in the laundry; and (b) performing the washing stroke based on the washing conditions.
[0019] At this time, the step (a) for selecting the anti-yellow course uses a hot key for directly performing the anti-yellow course.
[0020] Also, the washing conditions of the step (a) includes a temperature (T1) of washing water which is optimal to activate deposition of protein of the laundry.
[0021] Also, the washing conditions of the step (a) includes a washing time period (t1) and a temperature (T1) of the washing water which are optimal to activate the deposition of protein of the laundry.
[0022] Further, the temperature (T1) of the washing water for the anti-yellow course is about 40° C.
[0023] The washing time period (t1) of the anti-yellow course is longer than a washing time period of a normal course.
[0024] In addition, a heating means for heating the washing water held in a tub is provided for the step (B) of performing the anti-yellow course.
[0025] In another aspect of the present invention, a method for controlling a course of a washing machine including a heating means for heating washing water held in a tub comprises (a) operating the heating means to thereby heat the washing water to a preset temperature (T1) for activating deposition of protein of the laundry; and (b) performing an anti-yellow course by controlling the heating means to thereby maintain the preset temperature (T1) of the washing water for a preset time period (t1).
[0026] At this time, the preset temperature (T1) of the washing water is maintained about 40° C. which is optimal to activate the deposition of protein of the laundry.
[0027] Also, the preset time period (t1) of the anti-yellow course is longer than a washing time period of a normal course.
[0028] In another aspect of the present invention, a method for controlling a course of a washing machine comprises (a) setting washing conditions for destroying bacilli from the laundry when an anti-bacteria course is selected; and (b) performing a washing stroke for the laundry according to the preset washing conditions.
[0029] At this time, the step (a) for selecting the anti-bacteria course uses a hot key for directly performing the anti-bacteria course.
[0030] Also, the washing conditions of the step (a) for the anti-bacteria course includes an optimal temperature (T2) of washing water at which various bacilli of the laundry and a tub are destroyed effectively.
[0031] Also, the washing conditions of the step (a) for the anti-bacteria course includes a washing time period (t2) and a temperature (T2) of the washing water which are effective in destroying various bacilli of the laundry and a tub.
[0032] Further, the temperature (T2) of the washing water for the anti-bacteria course is higher than a temperature of washing water for a normal course. Also, the temperature (T2) of the washing water for the anti-bacteria course is about 90° C. or more. Also, the washing time period (t2) of the anti-bacteria course is longer than a washing time period of the normal course.
[0033] In addition, a heating means for heating the washing water held in the tub is provided for the step (B) of performing the anti-bacteria course.
[0034] In another aspect of the present invention, a method for controlling a course of a washing machine including a heating means for heating washing water held in a tub comprises performing an anti-bacteria course which includes steps of (a) operating the heating means so as to heat the washing water to a preset temperature (T2), to thereby activate deposition of protein of the laundry; and (b) controlling the heating means so as to maintain the preset temperature (T2) of the washing water for a preset time period (t2).
[0035] At this time, the preset temperature (T2) of the washing water is higher than a temperature of washing water in a normal course using warm water.
[0036] Also, the preset temperature (T2) of the washing water is maintained at 90° C. or more, which is optimal to destroy bacilli from the laundry and the tub.
[0037] Also, the preset time period (t2) of the anti-bacteria course is longer than a washing time period of the normal course.
[0038] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
[0040] FIG. 1 is a cross sectional view of illustrating a drum washing machine according to the present invention;
[0041] FIGS. 2 and 3 illustrate a key panel including a corresponding hot key for an anti-yellow course or an anti-bacteria course in a washing machine according to the present invention;
[0042] FIGS. 4 and 5 are flowcharts of illustrating a washing stroke of an anti-yellow course according to the present invention; and
[0043] FIGS. 6 and 7 are flowcharts of illustrating a washing stroke of an anti-bacteria course according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0044] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0045] Hereinafter, a method for controlling a course of a washing machine according to the present invention will be explained with reference to the following drawings.
[0046] First, a structure of a drum washing machine will be described with reference to FIG. 1 .
[0047] As shown in FIG. 1 , the drum washing machine includes an outer case 1 which forms the exterior thereof; a door 3 which is provided in front of the outer case 1 , the door 3 through which the laundry is taken in or is taken out of the inside; and an outer tub 5 which is provided inside the outer case 1 so as to hold washing water.
[0048] In addition, an inner tub 7 is provided inside the outer tub 5 , wherein the inner tub 7 includes a plurality of water holes 7 a . The inner tub 7 is rotated at a high speed, to thereby dehydrate the laundry. Also, a lift 9 is provided at an inner side of the inner tub 7 , for lifting and dropping the laundry.
[0049] Also, a water supplying valve 11 and a water supplying hose 13 are provided at one side of the outer case 1 , to thereby supply the washing water.
[0050] A detergent box 15 is provided at an inner upper side of the outer case 1 , to thereby supply detergent required for washing. Also, a water supplying bellows 17 is provided at one side of the detergent box 15 and outer tub 5 , to thereby supply the washing water containing the detergent, according as the washing water flows into the detergent box 15 through the water supplying hose 13 , to the outer tub 5 . The water supplying bellows 17 is expanded and jointed to the outer tub 5 .
[0051] Also, a motor 19 for generating a power is provided at one side of the outer tub 5 . A belt 21 and a pulley 23 are provided at one side of the motor 19 so as to transmit a rotary power of the motor 19 to the inner tub 7 , whereby the inner tub 7 is rotated at a forward/backward direction.
[0052] Then, a water draining bellows 25 is provided at a lower side of the outer tube 5 , so as to drain the washing water contaminated after completing the washing process from the washing machine. Also, a water draining pump 27 is provided at one side of the water draining bellows 25 to pump the washing water drained through the water draining bellows 25 . A water draining hose 29 is provided at one side of the water draining pump 27 , so as to drain the water out of the washing machine to the outside.
[0053] There is a water level sensor 31 that is provided at one inner side of the outer case 1 , to sense a level of the water provided to the inside of the outer tube 5 through a water pressure. Also, a water level hose 33 transmits the water pressure inside the outer tub 5 to the water level sensor 31 .
[0054] Also, a gasket 35 is provided between the outer tub 5 and the door 3 , wherein the gasket 35 prevents the washing water held in the outer tube 5 from leaking.
[0055] A heater 41 is provided between the lower side of the outer tub 5 and the inner tub 7 , wherein the heater 41 heats the washing water. A water temperature sensor 43 senses a temperature of the washing water held in the outer tub 5 and heated by the heater 18 , and transmits the sensed temperature to a system micom (not shown).
[0056] Preferably, a hot key for an anti-yellow or anti-bacteria course is provided in a control panel (not shown) of the washing machine, to thereby realize a direct selection to the anti-yellow or anti-bacteria course by the user.
[0057] First, as shown in FIG. 2 , the control panel includes the hot key 50 for inputting the anti-yellow course, and a display part 60 for displaying whether the inputted anti-yellow course is selected or not.
[0058] As shown in FIG. 3 , the control panel includes the hot key 70 for inputting the anti-bacteria course, and a display part 80 for displaying whether the inputted anti-bacteria course is selected or not.
[0059] As the user selects the hot key 50 or 70 corresponding to the anti-yellow course or the anti-bacteria course, the anti-yellow or anti-bacteria washing stroke is performed, and the corresponding washing state is displayed on the display part 60 or 80 during performing the anti-yellow or anti-bacteria washing stroke.
[0060] The anti-yellow washing stroke using the above drum washing machine according to the present invention will be described with reference to FIGS. 4 and 5 .
[0061] First, after the user puts the laundry into the inside of the washing machine, the user selects the desired stroke course. At this time, whether the user selects the anti-yellow course or not is sensed (S 10 ).
[0062] If the user selects the anti-yellow course, a first preset time period t1 is determined as a washing stroke time, and a first preset temperature T1 is determined as a temperature of the washing water for the anti-yellow course.
[0063] In this state, according as the heater 41 is turned on, the washing water is heated to the first preset temperature T1. That is, the washing stroke for removing dirt from the laundry is performed during the first preset time period t1 (S 20 ).
[0064] At this time, the anti-yellow course controls the heater 41 to be turned on/off alternatively and repetitively, to thereby maintain the first preset temperature T1 during performing the anti-yellow course.
[0065] In the meantime, if the user selects not the anti-yellow course but a normal course, a preset washing stroke time period t0 is selected, and the heater 41 is turned off, whereby the washing stroke is performed during the preset washing stroke time period t0 in state of turning off the heater 41 (S 30 ).
[0066] At this time, preferably, the first preset time period t1 of the anti-yellow course is longer than the preset washing stroke time period t0 of the normal course.
[0067] On completing the washing stroke of the corresponding preset time period according to the washing course selected by the user, rinsing and spin-drying strokes (S 40 and S 50 ) are performed in sequence. The rinsing stroke (S 40 ) is performed to rinse the laundry in the clean water, to thereby remove detergent and contaminants from the laundry. The spin-drying stroke (S 50 ) is performed by rotating the drum (inner and outer tubs) at a high speed, to thereby remove the moisture from the laundry.
[0068] In detail, the washing stroke of the anti-yellow course will be explained with reference to FIG. 5 .
[0069] First, after measuring the amount of laundry (S 21 ), the water level is determined corresponding to the measured amount of laundry.
[0070] After the water is supplied to the corresponding level (S 22 ), counting of washing time is started and the heater 41 is turned on, at the same time.
[0071] During the first preset time period t1, the washing stroke is performed in state of that the heater 41 is operated and the rotation and stop of the drum occur in alternation and repetition (S 23 and S 24 ).
[0072] At this time, the water temperature sensor 43 periodically reads the temperature of washing water heated by the heater 41 , whereby the heater 41 is repetitively turned on/off to thereby maintain the first preset temperature T1 of the washing water during performing the washing stroke.
[0073] Preferably, the washing water for the anti-yellow course is maintained at a temperature of 40° C. or more, at which the decomposition of protein is activated.
[0074] The anti-bacteria course of the present invention will be explained with reference to FIGS. 6 and 7 .
[0075] First, after the user puts the laundry into the inside of the washing machine, the user selects the desired stroke course. At this time, whether the user selects the anti-bacteria course or not is sensed (S 60 ).
[0076] If the user selects the anti-bacteria course, a second preset time period t2 is determined as a washing stroke time, and a second preset temperature T2 is determined as a temperature of the washing water for the anti-bacteria course. That is, the washing stroke for removing dirt and bacilli from the laundry is performed during the second preset time period t2 at the second preset temperature T2 (S 70 ).
[0077] In the meantime, if the user selects not the anti-bacteria course but a normal warm-water course, a washing stroke time period t0 and a temperature T0 of warm washing water, which are previously set according to the normal warm-water course, are selected. In this state, the washing stroke is performed during the time period t0 at the temperature T0 of the washing water (S 80 ).
[0078] Preferably, the second preset time period t2 of the anti-bacteria course is longer than the time period t0 of the normal warm-water course, and the second preset temperature T2 of the anti-bacteria course is higher than the temperature T0 of the normal warm-water course.
[0079] Especially, the second preset temperature T2 of the anti-bacteria course is set above the boiling point, for example, about 95° C. or more, at which the bacilli of the laundry is destroyed.
[0080] After completing the washing stroke of the preset time period according to the washing course selected by the user, rinsing and spin-drying strokes (S 90 and S 100 ) are performed in sequence. The rinsing stroke (S 90 ) is performed to rinse the laundry in the clean water, to thereby completely remove the detergent and contaminants from the laundry. The spin-drying stroke (S 100 ) is performed by rotating the drum (inner and outer tubs) at a high speed, to thereby remove the moisture from the laundry.
[0081] In detail, the washing stroke of the anti-bacteria course will be explained with reference to FIG. 7 .
[0082] First, after measuring the amount of laundry (S 71 ), the water level is determined corresponding to the measured amount of laundry.
[0083] After the water is supplied to the determined level (S 72 ), counting of washing time is started and the heater 41 is turned on, at the same time.
[0084] During the second preset time period t2, the washing stroke is performed in state of that the heater 41 is operated and the rotation and stop of the drum occur in alternation and repetition (S 73 and S 74 ).
[0085] At this time, the water temperature sensor 43 periodically reads the temperature of washing water heated by the heater 41 , whereby the heater 41 is repetitively turned on/off to thereby maintain the second preset temperature T2 of the washing water during performing the washing stroke.
[0086] The washing water is heated to the second preset temperature T2, and the heated washing water of high temperature is used for the washing stroke of the laundry, to thereby completely destroy the bacillus of the laundry.
[0087] As mentioned above, the method for controlling the course of the washing machine according to the present invention has the following advantages.
[0088] When performing the anti-yellow course, the washing water is maintained at the temperature which can activates the decomposition of protein, to thereby prevent the laundry from being contaminated and yellowed.
[0089] Also, the anti-bacteria course provides the washing algorism which is effective in destroying the various bacilli of the laundry and the tub, thereby improving the reliability of product.
[0090] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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A method for controlling a course of a washing machine is disclosed, to remove bacilli as well as protein contaminants from a washing tub and the laundry, which includes (a) selecting an anti-yellow course of a washing stroke, so as to set washing conditions which is suitable for activating deposition of protein in the laundry; and (b) performing the washing stroke based on the washing conditions.
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FIELD OF THE INVENTION
[0001] The present invention relates generally to chemical vapor deposition methods and apparatus.
BACKGROUND OF THE INVENTION
[0002] Chemical vapor deposition involves directing one or more gases containing chemical species onto a surface of a substrate so that the reactive species react and form a deposit on the surface. For example, compound semiconductors can be formed by epitaxial growth of a semiconductor material on a substrate. The substrate typically is a crystalline material in the form of a disc, commonly referred to as a “wafer.” Compound semiconductors such as III-V semiconductors commonly are formed by growing layers of the compound semiconductor on a wafer using a source of a Group III metal and a source of a group V element. In one process, sometimes referred to as a “chloride” process, the Group III metal is provided as a volatile halide of the metal, most commonly a chlorides such as GaCl 2 whereas the Group V element is provided as a hydride of the Group V element. In another process, commonly referred to as metal organic chemical vapor deposition or “MOCVD” the chemical species include one or more metal organic compounds such as alkyls of the Group III metals gallium, indium, and aluminum, and also include a source of a Group V element such as one or more of the hydrides of one or more of the Group V elements, such as NH 3 , AsH 3 , PH 3 and hydrides of antimony. In these processes, the gases are reacted with one another at the surface of a wafer, such as a wafer of sapphire, Si, GaAs, InP, InAs or GaP, to form a III-V compound of the general formula In x Ga y Al z N A AS B P C Sb D where X+Y+Z=approximately 1, and A+B+C+D=approximately 1, and each of X, Y, Z, A, B, and C can be between 0 and 1. In some instances, bismuth may be used in place of some or all of the other Group III metals.
[0003] In either process, the wafer is maintained at an elevated temperature within a reaction chamber. The reactive gases, typically in admixture with inert carrier gases, are directed into the reaction chamber. Typically, the gases are at a relatively low temperature, as for example, about 50-60° C. or below, when they are introduced into the reaction chamber. As the gases reach the hot wafer, their temperature, and hence their available energy for reaction, increases.
[0004] One form of apparatus which has been widely employed in chemical vapor deposition includes a disc-like wafer carrier mounted within the reaction chamber for rotation about a vertical axis. The wafers are held in the carrier so that surfaces of the wafers face upwardly within the chamber. While the carrier is rotated about the axis, the reaction gases are introduced into the chamber from a flow inlet element above the carrier. The flowing gases pass downwardly toward the carrier and wafers, desirably in a laminar plug flow. As the gases approach the rotating carrier, viscous drag impels them into rotation around the axis, so that in a boundary region near the surface of the carrier, the gases flow around the axis and outwardly toward the periphery of the carrier. As the gases flow over the outer edge of the carrier, they flow downwardly toward exhaust ports disposed below the carrier. Most commonly, this process is performed with a succession of different gas compositions and, in some cases, different wafer temperatures, to deposit plural layers of semiconductor having differing compositions as required to form a desired semiconductor device. Merely by way of example, in formation of light emitting diodes (“LEDs”) and diode lasers, a multiple quantum well (“MQW”) structure can be formed by depositing layers of III-V semiconductor with different proportions of Ga and In. Each layer may be on the order of tens of Angstroms thick, i.e., a few atomic layers.
[0005] Apparatus of this type can provide a stable and orderly flow of reactive gases over the surface of the carrier and over the surface of the wafer, so that all of the wafers on the carrier, and all regions of each wafer, are exposed to substantially uniform conditions. This, in turn promotes uniform deposition of materials on the wafers. Such uniformity is important because even minor differences in the composition and thickness of the layers of material deposited on a wafer can influence the properties of the resulting devices.
[0006] The wafer temperature normally is set to optimize the desired deposition reaction; it is commonly above 400° C. and most typically about 700°-1100° C. It is generally desirable to operate equipment of this type at the highest chamber pressure, lowest rotation speed and lowest gas flow rate which can provide acceptable conditions. Pressures on the order of 10 to 1000 Torr, and most commonly about 100 to about 750 Torr, are commonly used. Lower flow rates are desirable to minimize waste of the expensive, high-purity reactants and also minimize the need for waste gas treatment. Lower rotation speeds minimize effects such as centrifugal forces and vibration on the wafers. Moreover, there is normally a direct relationship between rotation speed and flow rate; under given pressure and wafer temperature conditions, the flow rate required to maintain stable, orderly flow and uniform reaction conditions increases with rotation rate.
[0007] Prior to the present invention, however, the operating conditions which could be used were significantly constrained. It would be desirable to permit lower rotation speeds and gas flows, higher operating pressures, or both, while still preserving the stable flow pattern.
SUMMARY OF THE INVENTION
[0008] One aspect of the invention provide methods of chemical vapor deposition. A method according to this aspect of the invention desirably includes the step of supporting one or more substrates on a carrier within a reaction chamber so that surfaces of the substrates face upwardly within the chamber, while rotating the carrier about a vertical axis and maintaining the substrates at a substrate temperature of 500° C. or higher. The method desirably also includes the step of directing gases, most preferably gases which include a Group III metal source and a Group V compound, into the chamber from an inlet element disposed above the substrates. The gases flow downward toward the substrates and outwardly away from the axis over the surfaces of the substrates and react to form a deposit such as a III-V semiconductor on the substrates. The gases most preferably are at an inlet temperature above about 75° C., and more preferably above about 100° C. such as about 100° C. to about 250° C. when introduced into the chamber. Preferably, the walls of the chamber are maintained at a temperature within about 50° C. of the inlet temperature.
[0009] Preferred methods according to this aspect of the invention can provide significant improvements in operating range. In particular, the preferred methods according to this aspect of the invention can operate at lower rotational speeds, lower gas flow rates, and higher pressures than similar processes using lower gas inlet temperatures.
[0010] A further aspect of the present invention provides a chemical vapor deposition reactor. The reactor according to this aspect of the invention desirably is a rotating-disc reactor, and desirably includes a flow inlet temperature control mechanism arranged to maintain the flow inlet element of the reactor at an inlet temperature as discussed above in connection with the method. Most preferably, the reactor also includes a chamber temperature control mechanism arranged to maintain the walls of the chamber at a wall temperature as discussed above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a diagrammatic view of a reactor according to one embodiment of the invention.
[0012] FIG. 2 is a diagrammatic sectional view depicting a component of the reactor shown in FIG. 1 .
[0013] FIG. 3 is a schematic view of another component of the reactor shown in FIG. 1 .
[0014] FIGS. 4 and 5 are graphs depicting certain operating conditions.
DETAILED DESCRIPTION
[0015] Apparatus according to one embodiment of the invention ( FIG. 1 ) includes a reaction chamber 10 having a central axis 12 . In this embodiment, axis 12 is substantially vertical as seen in the normal gravitational frame of reference. The interior walls of chamber 10 are generally in the form of surfaces of revolution about axis 12 . In a flow region 14 at the top of the chamber, the interior wall 16 is substantially in the form of a cylinder having diameter d FR concentric with the axis. A region 18 , referred to herein as the “carrier region,” has a cylindrical interior wall 20 which is also generally in the form of a cylinder concentric with axis 12 and having diameter d CR larger than d FR . The chamber has a downwardly-facing transition surface 22 at the juncture of the flow region and carrier region. The chamber also has an exit region 24 disposed below the carrier region. The chamber walls have passageways schematically indicated at 26 for passage of a temperature control fluid within the walls as discussed below. Although the walls of the chamber are depicted as unitary elements in FIG. 1 , in actual practice the walls may be formed from multiple elements. Also, the walls may include movable sections such as sections defining doors for transferring wafers into and out of the chamber. Merely by way of example, part or all of the interior wall in the carrier region may be defined by a ring-like shutter which is movable in the axial directions, as shown in U.S. Pat. No. 6,902,623, the disclosure of which is hereby incorporated by reference herein. Unless otherwise indicated, description of the chamber and other elements of the apparatus should be understood as referring to the configuration of the apparatus in an operative condition usable for depositing materials.
[0016] The apparatus has a wafer carrier drive mechanism, which includes a spindle 28 extending into chamber 10 . The spindle is coaxial with axis 12 and rotatable about the axis. The wafer carrier drive mechanism also includes a rotary drive mechanism 30 such as an electric motor connected to the spindle. The apparatus also includes conventional elements such as bearings and vacuum-tight rotary seals (not shown).
[0017] A wafer carrier 30 is mounted on the spindle. The wafer carrier in this embodiment is a disc-like body formed from a refractory, inert material such as molybdenum, graphite or silicon carbide. The carrier has a generally planar top surface 34 and pockets 36 formed in the top surface. The pockets are arranged to hold a plurality of wafers 38 so that surfaces 40 of the wafers are exposed and are coplanar or nearly coplanar with the top surface 34 of the carrier. In the operative condition shown, the wafer carrier is engaged with spindle 28 . The spindle supports the carrier within the carrier region 18 of the chamber with the top surface 34 and wafer surfaces facing upwardly, toward the top of the chamber, such surfaces being substantially perpendicular to axis 12 . The diameter d C of carrier 32 is less than the diameter d CR of the carrier region 18 , so that the periphery of the carrier and the inner wall 20 of the carrier region define a ring-like gap 41 surrounding the carrier and communicating with the exit region 24 of the chamber. For example, in a system with a wafer carrier of about 12.5 inches (31.75 cm) diameter d C , d CR may be about 15.5 inches (39.4 cm). In this embodiment, the interior diameter d FR is approximately equal to the diameter d C of the wafer carrier or slightly larger than d C . Typically, the wafer carrier is detachably mounted on the spindle, so that the apparatus can be reloaded by removing the wafer carrier from the spindle and replacing it with another carrier bearing new wafers.
[0018] A heater 42 , as for example, a resistance heating element, is disposed within the reaction chamber for heating the substrate 32 carrier. An exhaust system 44 is connected to the exit region 24 of the chamber. The exhaust system is arranged to draw gasses from the interior of the chamber. The exhaust system desirably includes a controllable element such as a variable-speed pump or throttling valves 45 which can be adjusted to maintain a desired pressure within the chamber.
[0019] A flow inlet element 46 is mounted to the flow region 14 of the chamber and forms the top wall of the chamber. The flow inlet element is disposed above the carrier region 18 and above the wafer carrier 32 . The flow inlet element is connected to sources 55 and 56 of the gases used in the process. The flow inlet element directs streams of the various gases into the reaction chamber and downwardly toward the wafer carrier and substrates. As further discussed below, the gas streams form a substantially laminar plug flow within flow region 14 of the chamber. Typically, the flow inlet element is arranged to discharge the gases over the entire cross-sectional area of the flow region. Stated another way, the cross-sectional area of the plug-like laminar flow, viewed in a horizontal plane perpendicular to axis 12 , desirably has a diameter close to the interior diameter dF of the flow region. The diameter of the flow as seen in such cross-section desirably is approximately equal to or slightly greater than the diameter d C of carrier 32 . Typically, the flow inlet element has openings distributed over its downwardly-facing bottom surface 48 , these openings being connected to the gas sources. Merely by way of example, the flow inlet element may be arranged as shown in FIG. 2 , with first inlets disposed in arrays distributed over regions such as quadrants 50 of the flow inlet bottom surface 48 and with second inlets distributed in radially-extending rows 52 . The first inlets typically are connected to a source 54 ( FIG. 1 ) of a Group V element such as a hydride, whereas the second inlets typically are connected to a source 56 ( FIG. 1 ) of a Group III metal such as a metalorganic. These gas sources normally are arranged to provide the active reagents in admixture with a carrier gas such as N2 or H2 which does not participate in the deposition reaction. The flow inlet element also may have additional openings in its bottom surface for discharge of a carrier gas without active reagents, supplied by a separate source 55 . For example, as disclosed in U.S. Published patent application Ser. No. 11/192,483, the disclosure of which is hereby incorporated by reference, the carrier gas may be discharged between streams of Group V and Group III elements so as to suppress mixing of these streams and undesired reactions in the vicinity of the flow inlet element. Also, as disclosed for example in U.S. Published Patent Application No. 20070134419, the disclosure of which is also incorporated by reference herein, the flow rates and compositions of the various gas streams may be selected to provide similar gas density and flow rate in the various gas streams. Flow inlet element 46 has temperature control fluid passages indicated schematically at 58 for passage of a temperature control fluid.
[0020] The foregoing features of the apparatus may be similar to those used in the reactors sold under the registered trademark TURBODISC by Veeco Instruments, Inc. of Plainview, N.Y., USA.
[0021] The temperature control fluid passages 58 of the flow inlet element 46 are connected to a flow inlet temperature control mechanism 60 . One example of a control mechanism is depicted in FIG. 3 . This control mechanism includes a pump 62 for circulating a fluid, most preferably a liquid such as water, ethylene glycol, a hydrocarbon oil or a synthetic organic heat transfer liquid such as those sold under the registered trademark DOWTHERM, through the temperature control fluid passages 58 of the fluid inlet element. The control mechanism also includes one or more sensors 64 for monitoring at least one temperature of the flow inlet element, the gases discharged from the flow inlet element, or the circulating fluid. The control mechanism desirably also includes a structure such as a radiator 65 arranged to dissipate heat from the circulating fluid into the environment, and also may include a heater such as an electrical resistance heater 66 or other element arranged to supply additional heat to the circulating fluid. The temperature control mechanism desirably further includes a control circuit 68 connected to the one or more sensors 64 and arranged to control operation of the heat-abstracting and heat-applying elements. In the particular embodiment depicted, the control circuit can vary the amount of heat abstracted from the fluid by controlling a bypass valve 70 to divert part or all of the circulating fluid away from the radiator, and can vary the amount of heat supplied to the fluid by controlling the operation of an electrical power supply 72 connected to the resistance heater. Many other arrangements of heat transfer elements can be employed, and these arrangements need not include a circulating fluid. For example, the flow inlet element can be provided with fins which dissipate heat directly into the atmosphere and with electrical heaters embedded in its structure. In such an arrangement, the temperature of the flow inlet element can be controlled by varying air flow over the fins, by controlling operation of the resistance heaters, or both. It is also possible to control the temperature of the flow inlet element and of the gases discharged from the flow inlet element by cooling or heating the gasses passing into the flow inlet element. Also, during operation, heat is transferred to the flow inlet element from the wafer carrier and wafers. Therefore, it is not essential for the flow inlet temperature control apparatus 60 to include a heat-supplying device such as resistance heater 66 . The inlet temperature control apparatus 60 may be arranged to control the temperature of different zones of the flow inlet element separately. For example, the temperature control fluid passages 58 may include separate flow loops for different zone of the flow inlet element, and the temperature control apparatus may include separate subsystems associated with each such loop.
[0022] The flow inlet element 48 desirably is formed from metals or other materials having substantial thermal conductivity, and the gas passages (not shown) within the flow inlet element desirably are in intimate contact with the flowing fluid in passages 58 , so that the temperature of the gases discharged from the flow inlet element and the temperature of the flow inlet element itself are close to the temperature of the heat transfer fluid. The flow inlet temperature control apparatus 60 is arranged to maintain the flow inlet element and the gases passing from the flow inlet element into the reaction chamber at an inlet temperature above about 75° C., more desirably above about 100° C, such as about 100° C. to about 250° C., and most typically 100° C. to 250° C.
[0023] The apparatus also includes a wall temperature control apparatus 74 ( FIG. 3 ). The wall temperature control apparatus may be connected to the temperature control fluid passages 26 in the walls of chamber 10 , and may include elements similar to those of the inlet temperature control apparatus 60 . The wall temperature control apparatus desirably is arranged to maintain the chamber walls in flow region 14 , and desirably in the carrier region 18 as well, at a wall temperature within the ranges discussed above fro the inlet temperature. Preferably, the wall temperature is close to the inlet temperature as, for example, within about 50° C., and more preferably within about 25° C., of the inlet temperature. The wall temperature control apparatus 74 may include multiple elements for separately controlling the temperature of individual zones of the chamber wall.
[0024] In a processing method according to one embodiment of the invention, the gas sources 54 - 56 are actuated to supply a flow of gases including the Group III and Group V elements, and typically also including a carrier gas, as a laminar, downward plug flow towards the wafer carrier 32 and wafers 38 . The gas flow rate typically is about 25 to about 250 standard ml per minute per cm 2 of area cross-sectional area of the plug flow, as seen in a horizontal plane perpendicular to axis 12 . Because the area of the plug flow as seen in such plane is close to the exposed area of the wafer carrier top surface 34 and wafer top surfaces 40 , the gas flow rate computed on the basis of the carrier and wafer area typically is about the same, i.e., about 25 to about 250 standard ml per minute per cm 2 of area. For example, in a system with a wafer carrier of about 12.5 inches (31.75 cm) diameter, the flow rate is commonly about 50-300 standard liters per minute, i.e., about 60-400 standard ml/min per cm 2 of exposed surface area of the wafer carrier and wafer carrier. As used in this disclosure with reference to a gas, a “standard” liter or ml refers to a volume of gas at 25° C. (298 and 1 atm absolute pressure. The exhaust system 44 is controlled so as to maintain a desired pressure within the reaction chamber as, for example, above about 10 Torr, more preferably above about 100 Torr, and typically about 250 Torr to about 1000 Torr, most commonly about 250 Torr to about 750 Torr. The rotary drive 30 is actuated to turn the spindle 28 and hence wafer carrier 32 around the axis 12 at a desired rotation rate, typically above about 25 revolutions per minute, and more typically about 100 to about 1500 revolutions per minute. Heater 42 is actuated to maintain the wafer carrier and substrates at a desired substrate temperature, typically above about 400° C., more commonly about 700° C.-1100° C. The substrate temperature normally is selected to optimize the kinetics of the deposition reaction.
[0025] As the wafer carrier 18 is rotating rapidly, the surface of the wafer carrier and the surfaces of the wafers are moving rapidly. The rapid motion of the wafer carrier and wafers entrains the gases into rotational motion around axis 12 , and radial flow away from axis 12 , and causes the gases in the various streams to flow outwardly across the top surface 34 of the wafer carrier and across the exposed surfaces 40 of the wafers within a boundary layer schematically indicated at 76 in FIG. 1 . Of course, in actual practice, there is a gradual transition between the generally downstream flow regime denoted by the arrows in the flow region 14 and the flow in the boundary layer 76 . However, the boundary layer can be regarded as the region in which the gases flow substantially parallel to the surfaces of the wafers. Under typical operating conditions, the thickness T of the boundary layer is about 1 cm or so. By contrast, the vertical distance from the downstream face of flow inlet element to the surfaces 40 of the wafers commonly is about 5-8 cm.
[0026] The rotational motion of the wafer carrier pumps the gases outwardly around the peripheral edges of the wafer carrier, and hence the gases pass over the edge of the wafer carrier and downwardly through the gap 41 between the wafer carrier and interior wall 20 of the carrier region. The gasses passing through the gap pass to exhaust system 44 . A vortex 80 typically forms near the interior wall 20 and downwardly-facing wall 22 . Provided that this vortex remains remote from the wafer carrier and wafers, it does not disrupt the smooth, uniform flow of gases over the wafer surfaces. In general, the vortex tends to increase with the rotational speed of the wafer carrier. If the rotational speed of the carrier is too low, however, recirculation occurs near the central axis 12 . This recirculation is caused by convection; gases heated by the hot wafer carrier and wafers become less dense and tend to rise. Recirculation of this nature also will disrupt the smooth flow of gases over the wafer surfaces. Both of these problems tend to become more severe with increasing pressure within the reactor. The desired operating condition, referred to herein as “non-recirculating” operation, occurs when the vortex near interior wall 20 does not extend over the wafer carrier, and when recirculation near the central axis 12 does not occur.
[0027] These effects are illustrated in FIG. 4 . FIG. 4 represents results derived by computational flow dynamics for a particular reactor operating at a gas flow rate, gas composition, substrate temperature and gas inlet temperature, shown on a graph of pressure and rotation rate. Pressure and rotation rate below the solid-line curve in FIG. 4 represent non-recirculating operation, whereas pressure and rotation rate above the solid-line curve represent undesirable conditions. The minimum rotation rate which can be used at a given pressure is governed by convective recirculation. For example, at a pressure of 300 Torr, (solid horizontal line) minimum usable rotation rate is about 260 rpm; below that rate, there is recirculation near the axis due to convection. The maximum rotation rate which can be used at a given pressure is limited by the vortex at the edge of the wafer carrier. At 300 Torr, the maximum rotation rate is about 700 rpm. At higher pressures, the minimum rate increases and the maximum rate decreases, so that at pressure of about 480 Torr, the minimum and maximum rates are equal. This means that there is no rotation rate where this system, with the given gas flow rate, gas composition, substrate temperature and gas inlet temperature can operate in a non-recirculating regime at a pressure of about 480 Torr or above.
[0028] Although the present invention is not limited by any theory of operation, the shape of the curve in FIG. 4 can be understood by consideration of certain dimensionless numbers and ratios of the same. The Reynolds number Re defined by Formula 1 below provides a measure of the significance of forced convection.
[0000]
Re
=
ρ
mix
v
mix
d
μ
mix
(
Formula
1
)
[0029] The Rotational Reynolds number Re ω defined by Formula 2 below provides a measure of the significance of forced convection due to the rotation of the wafer carrier.
[0000]
Re
ω
=
ρ
mix
ω
d
2
μ
mix
(
Formula
2
)
[0030] The Grashof number Gr defined by Formula 3 below provides a measure of the significance of natural convection.
[0000]
Gr
=
g
ρ
mix
2
H
3
·
(
t
s
-
t
w
)
μ
mix
2
t
w
(
Formula
3
)
[0031] In each of Formulas 1-3:
[0032] ρ mix , μ mix , ν mix represent density, viscosity and velocity of the gas mixture, respectively.
[0033] ω is the angular velocity of the wafer carrier.
[0034] d is the diameter of the wafer carrier.
[0035] H is the vertical distance between the flow inlet element and the wafer carrier top surface.
[0036] t s is the substrate temperature.
[0037] t w is the reactor wall temperature, which is assumed to be equal to the inlet temperature t i .
[0038] Criteria for non-recirculating operation are defined by critical values of certain dimensionless ratios of Re, Re ω and Gr, as indicated in Formula 4, below. These ratios represent the ratio of the relative strengths of different forces in the reactor.
[0000]
Gr
Re
·
Re
ω
≤
C
1
;
Gr
Re
m
≤
C
2
;
Re
ω
Re
n
≤
C
3
(
Formula
4
)
[0039] At very low rotational speeds, the effect of convection is counteracted only by the plug flow, and is substantially uninfluenced by rotation of the wafer carrier. Thus, as long as the inequality for constant C 2 is satisfied, recirculation near the axis due to convection does not occur. This is shown by the horizontal broken line in FIG. 4 . At higher rotational speeds, the effect of rotation becomes significant, and operation without recirculation due to convection occurs if the inequality for constant C 1 is satisfied. This is indicated by the upwardly-sloping broken line in FIG. 4 . The vortex outboard of the wafer carrier is enhanced by higher rotation speed but suppressed by greater outward flow. Operation without the vortex spreading over the edge of the carrier occurs if the inequality for constant C 3 is satisfied, as indicated by the curving broken line in FIG. 4 .
[0040] The effect of gas inlet temperature is shown in FIG. 5 . Each curve in FIG. 5 is similar to the solid-line curve of FIG. 4 . Here again gas flow rate, gas composition, and substrate temperature are fixed, and the different solid lines represent results computed for different gas inlet temperatures. For each curve, the gas inlet temperature ti and wall temperature tw are equal to one another. Raising the inlet temperature broadens the operating range in which non-recirculating conditions prevail. This effect is particularly pronounced at ti of above about 75° C., and particularly about 100° C. or higher. The curves for ti of 100° C. and 200° C. show non-recirculating operation at substantially higher pressures than the curves for ti of 25° C. and 50° C. Moreover, at operating pressures where non-recirculating operation can occur for ti of 25° C. or 50° C., the minimum rotational speed is substantially reduced at ti of 100° C. or 200° C. For example, at 400 Torr, a minimum rotational speed of almost 400 rpm is required to maintain non-recirculating operation at ti of 25° C., whereas the minimum rotational speed to maintain non-recirculating operation is only about 120 rpm for ti of 200° C. Thus, by increasing the inlet temperature, and desirably the wall temperature as well, the operating pressure can be increased, the rotational speed decreased, or both. Moreover, minimum flow rate for stable operation is directly related to rotational speed. As t i increases and rotational speed decreases, the required flow rate of gases through the reactor decreases substantially. These effects would continue for still higher t i . However, with conventional reagents such as Group III metal alkyls and Group V hydrides, it is ordinarily desirable to maintain t i below about 250° C. to limit undesirable side reactions such as formation of solid deposits on the flow inlet element. Where these undesirable reactions can be suppressed in other ways, t i above 250° C. can be used.
[0041] In part, these effects can be understood qualitatively. Gasses expand with increasing temperature. Therefore, for a given gas composition and given flow rate (expressed in standard liters per minute), the volumetric flow rate (expressed in liters per minute) increases with inlet temperature. The higher volumetric flow rate in turn means that the velocity of the gas in the downward plug flow is greater. This tends to counteract the effect of convection. Also, the greater volumetric flow rate means that the speed of the gas moving radially outwardly, away from the axis, is also increased. This tends to keep the vortex away from the wafer carrier.
[0042] Numerous variations and combinations of the features discussed above can be employed. For example, the size of the reactor and the configuration of the reactor walls can be varied. Also, although the foregoing discussion refers to deposition of III-V semiconductors, the invention can be employed in chemical vapor deposition of other materials, particularly those which require a high substrate temperature for deposition and which conventionally employ low gas inlet temperatures and wall temperatures. Chemical vapor deposition apparatus and processes which employ a gas inlet temperature less than the substrate temperature, and a temperature difference ΔT of at least about 200° C. between these temperatures are referred to in this disclosure as “cold wall” apparatus and processes. Typically, ΔT in cold wall apparatus and processes is more than 200° C., as, for example, about 400° C. or more or about 500° C. or more. For example, cold wall apparatus and processes are commonly used in chemical vapor deposition systems in which one or more of the reactive gasses includes an organic or metalorganic compound. Certain cold wall deposition apparatus includes a rotating carrier. For example, cold wall systems of this type can be used to form silicon carbide from reactive gases including silane and a lower alkyl such as propane. Other examples include chemical vapor deposition of diamond, diamond-like carbon, nitrides other than the Group III nitride semiconductors discussed above, and other carbides. The invention can be applied to these systems as well.
|
A chemical vapor deposition reactor and method. Reactive gases, such as gases including a Group III metal source and a Group V metal source, are introduced into a rotating-disc reactor and directed downwardly onto a wafer carrier and substrates which are maintained at an elevated substrate temperature, typically above about 400° C. and normally about 700-1100° C. to deposit a compound such as a III-V semiconductor. The gases are introduced into the reactor at an inlet temperature desirably above about 75° C. and most preferably about 100°-250° C. The walls of the reactor may be at a temperature close to the inlet temperature. Use of an elevated inlet temperature allows the use of a lower rate of rotation of the wafer carrier, a higher operating pressure, lower flow rate, or some combination of these.
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FIELD OF THE INVENTION
The present invention is related to electrical connectors and more particularly to connectors adapted to interconnect a daughter card to a mother board.
BACKGROUND OF THE INVENTION
Certain electrical connectors contain an array of electrical contacts having pin sections coextending from a mounting face of the connector to be received into respective through-holes of a circuit element such as a mother board to become electrically connected with circuits of the board. The dielectric housing of the connector includes passageways in which the contacts are respectively retained in selected spacings and positions so that the pin sections coextend in a selected pattern. Such connectors are adapted to be affixed to edges of daughter cards on an opposed or second face of the connector, with the contacts including other contact sections electrically connected to circuits on major surfaces of the daughter card proximate the edge thereof. Many such connectors are of the type including a card-receiving recess thereinto, with the other contact sections disposed along sides of the recess to enter biased engagement with the corresponding card traces, all permitting withdrawal of the card therefrom during unmating. For example, see U.S. Pat. No. 4,077,694.
In U.S. Pat. Nos. 5,409,384 and 5,348,488, is disclosed a connector utilizing an element of flexible film circuitry for electrical interconnection of contacts of the daughter card to contacts of the connector. The dielectric housing has a thin substantially planar body section defining a board-proximate face and a board-remote face, an array of contact members including pin sections coextending from the board-proximate face of the body section to be received into corresponding through-holes of a mother board, and short second pin sections coextending from the board-remote face. The flexible circuit element includes defined thereon an array of circuits extending from termini located in a first interconnecting region associated with the second pin sections in a complementary pattern, along at least one side portion of the element formed upwardly from sides of the housing to contact sections exposed in at least one second interconnection region and associated with an array of circuits disposed on a surface of a daughter card to be interconnected therewith.
The termini include pin-receiving apertures therethrough, so that when the flexible circuit element is properly oriented and its first interconnecting region pressed against the array of second pin sections of the connector contacts, the second pin sections enter through the pin-receiving apertures. With the traces and trace termini defined on the housing-remote surface of the flexible circuit element, the second pin sections protruding above the associated termini can easily be soldered thereto to establish the electrical connections. The side portion or portions of the flexible circuit element is or are then formed upwardly. Potting material is then deposited atop the first interconnecting region to a selected thickness, embedding and sealing and protecting the electrical connections, and also providing a mechanical retention of the flexible circuit element to the connector housing.
In one embodiment of connector disclosed in U.S. Pat. No. 5,409,384, the flexible circuit element includes opposing side portions upwardly formed for second interconnecting regions on each to oppose each other and define a card-receiving region therebetween, into which an edge of a card is inserted for the traces on both surfaces to be soldered to exposed trace sections of the flexible circuit element. In another embodiment for a connector with fewer contacts, one such side portion and second interconnecting region extends upwardly to be secured to a corresponding surface of a daughter card and the exposed traces soldered to respective traces on that surface. The connectors provide a low profile board-to-board connector adapted for use in very confined spaces especially in a closely spaced array, wherein the electrical connections of the flexible film circuitry to contacts of the connector are sealed for long-term in-service life.
SUMMARY OF THE INVENTION
The present invention provides a low profile board-to-board connector that incorporates a flexible film circuit element for connecting traces of a daughter card to contacts of the connector which contacts include pin sections for interconnecting to circuits of a mother board at through-holes thereof. A premolded dielectric plate is provided above the array of solder joints of the flexible circuit element traces to the connector contacts. An array of holes corresponding to the sites of the soldered electrical connections permits potting compound to be disposed in the holes around the solder joints embedding and sealing the electrical connections. Control of the flow of potting compound results, with a defined boundary to the potted board-remote interface. The plate may be adhered to the surface of the flexible film circuit element prior to potting, if desired, and the plate thus adhered and potted provides strain relief benefits.
An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a PRIOR ART connector having a flexible circuit element electrically connected to contacts of the connector, wherein the electrical connections along the top connector surface are embedded in a layer of potting compound of selected depth;
FIG. 2 is an elevation view of the connector of the present invention having a portion of a flexible circuit element extending for eventual interconnection of its traces to those of a daughter card, and the connector including a dielectric plate surrounding the upper ends of a guide post and the contacts soldered to the film's circuits;
FIG. 3 is a plan view of the flexible circuit element of FIG. 2;
FIG. 4 is a plan view of the connector of FIG. 2 prior to affixing thereto the flexible circuit element, illustrating the upper contact sections of the connector;
FIGS. 5 to 7 show the method of assembling the connector of FIGS. 2 to 4, by placement of the flexible circuit element and soldering of its traces to the connector contacts, placement of the plate thereonto, and placement of potting compound in the plate holes embedding the solder joints and the guide post ends; and
FIG. 8 illustrates an alternate embodiment having four rows of connector contacts and a corresponding flexible circuit element having two opposed daughter card interconnection regions.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a connector of the prior art, such as that disclosed in U.S. Pat. Nos. 5,409,384 and 5,348,488. Connector assembly 10 includes a dielectric housing 12 with an array of contacts 14 affixed thereto in two rows, having pin sections 16 depending from a board mounting face 18 of housing 12 for eventual insertion into through-holes of a mother board (not shown). An organizer or alignment plate 20 is shown disposed below the housing and along free ends of the contact pins sections and the guide posts 22 at each end of the array, for maintaining the pin sections aligned to facilitate board mounting, with the organizer movable along the pin sections toward and to the housing during board mounting. Flexible film circuit element 24 includes circuits electrically connected to upper sections of contacts 14 at a first interconnection region 26, and the circuits extend to exposed portions 28 at a second interconnection region 30 for eventual electrical connections to corresponding traces of a daughter card (not shown). Potting compound 32 is shown applied to the upper face of the connector to a selected depth embedding the electrical connections of the traces to the connector contacts and also upper ends of guide posts 22. Embossments 34 are disposed at each corner of the upper face of the connector housing, serving to provide housing surface to which the potting compound is adhered to enhance the bond.
The present invention is illustrated in FIGS. 2 to 7 with an alternate embodiment shown in FIG. 8. Connector 50 is configured to be similar to connector 10 of FIG. 1 in most ways. A dielectric housing 52 includes an array of contacts 54 affixed thereto in two rows, having pin sections 56 depending from a board mounting face 58 for eventual insertion into through-holes of a mother board (not shown). An alignment plate 60 of dielectric material is shown disposed below the housing and along free ends of the contact pins sections and the guide posts 62 at each end of the array, for maintaining the pin sections aligned to facilitate board mounting, with the plate movable along the pin sections toward and to the housing during board mounting. Flexible film circuit element 64 includes circuits electrically connected to upper sections 66 of contacts 54 by soldering at a first interconnection region 68 along upper or card-proximate face 70, and the circuits extend to exposed portions 72 at a second interconnection region 74 for eventual electrical connections to corresponding traces 76 of a daughter card 78. Embossments 80 are disposed at each corner of the upper face of the connector housing.
In accordance with the present invention, a plate 82 of dielectric material is utilized to traverse the card-proximate face 70 of the connector atop the upper surface of first interconnection region 68 of flexible circuit element 64. End flanges 84 are disposed between each pair of embossments 80 at each end of the connector. Holes 86 extend through plate 82 at each location of a solder connection between an upper contact section 66 and a circuit trace, and also at the upper end 88 of each guide post 62. Potting compound 98 is disposed in each hole 86 to embed and thus seal each electrical connection therein.
The pattern of traces of an example flexible circuit element 64 is seen in FIG. 3, and at first interconnection region 68 each trace 90 includes an annular ring 92 surrounding a pin-receiving aperture 94 at each site of an upper contact section of the connector, for soldering thereto, and also an exposed portion 72 at second interconnection region 74 for eventual connection with a trace 76 of a daughter card 78 (FIG. 2). Upper or card-proximate connector face 70 of connector 50 is shown in FIG. 4 showing upper contact sections 66 and upper ends of guide posts 62.
FIGS. 5 to 7 depict the assembling of connector 50. In FIG. 5, the traces of flexible circuit element 64 have been soldered to respective upper pin sections 66 of the connector extending above card-proximate face 70 of housing 52. Preferably a thin layer of potting compound 96 such as epoxy resin (or another adhesive material) may be disposed over first interconnection region 68 prior to placement of plate 82 thereover, bonding it to the flexible film element and the housing. In FIG. 6, plate 82 has been placed in position to housing 52 and flexible circuit element 64, with upper pin sections 66 and the terminations to the traces disposed in respective apertures 86 of plate 82; the apertures should be large enough to contain the entire solder joint when plate 82 is disposed against the surface of the flexible film element. In FIG. 7, apertures 86 have been filled with potting compound 98.
An alternate embodiment of the present invention is illustrated in FIG. 8. Connector 100 includes four rows of contacts 102 retained within housing 104, and flexible circuit element 106 includes traces extending from first interconnection region 108 and terminations to respective ones of the two rows of contacts thereat, to a pair of opposed second interconnection regions 110 disposed on end sections 112. End sections 112 will be disposed along opposed major surfaces of a two-sided daughter card for the exposed trace portions 114 to become terminated to the corresponding traces on the daughter card. Plate 116 includes four rows of apertures 118 corresponding to the terminations of the flexible circuit traces to the associated connector contacts 102, and the apertures 118 are filled with potting compound 120 as in FIG. 7.
The use of plates 82,116 provides enhanced strain relief protecting the terminations of the traces of the flexible circuit element to the connector contacts if stress is applied to the flexible circuit element relative to the connector. The plates also provide control over the flow of potting compound used in the prior art. Such potting compound may be for example, an epoxy resin. The housing, the organizer and the plate may all be molded for example of a thermoplastic resin such as VECTRA glass-filled LCP polyester sold by Hoechst-Celanese Corp. of Chatham, N.J. The film layers of the flexible circuit element may be adhesive-backed KAPTON polyimide film sold by E. I. DuPont de Nemours & Co. of Wilmington, Del.
Variations and modifications may occur to the specific embodiments of the invention disclosed herein, that are within the spirit of the invention and the scope of the claims.
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A connector (10) for interconnecting a daughter card to a mother board using a flexible circuit element (64) joining the connector contacts (54) to the daughter card traces (76), while pin sections (56) of the contacts depend from the connector for insertion into mother board through-holes. A plate (82) of dielectric material is placed atop the terminations of the flexible circuit element to the contacts, with plate apertures (86) receiving the upper contact sections (66) and solder terminations thereinto, with potting compound (98) then placed in the apertures embedding and sealing the terminations, whereafter the plate provides enhanced strain relief.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation in part of U.S. Application No. Ser. 09/734,528, filed Dec. 11, 2000, which claims the benefit of U.S. Provisional Application No. 60/170,173, filed Dec. 10, 1999.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Use
[0003] The present invention relates to a method and apparatus for obtaining measurements of induced resistivity of objects from confined spaces such as within a down-hole hydrocarbon production well. It is well known that measuring the resistivity of an object or media can provide useful information regarding the composition and the location of object or media. The present invention utilizes the principles of Magnetic Antenna™ and Magnetic Lensing™ to obtain information regarding the location and properties of the target object. The present invention also relates to a method transmitting magnetic, electric, or acoustic energy through varying media to obtain phase differences in the energy that can be directionally oriented.
[0004] 2. Description of Related Art
[0005] In many applications of Inductive Resistivity Measurements (IRM), limitations of space or topography prevent the use of multiple antennas arrays. This lack of multiple antennas arrays causes the loss of directional information from received EM waves. An example of space limitations is in the down-hole environment of oil wells. IRM is used in this application for reservoir mapping or the detection of interfaces among oil, water and gas in a geologic formation. The accurate knowledge of the direction of the reflected EM wave is very important in these uses of IRM. Directionality determination must be made in both the vertical and azmuthal senses. Therefore there is a need for a device to encode the radiated EM signals in a way that yields directionality in space limited environments.
[0006] One requirement when obtaining useful or reliable Inductive Resistivity Measurements (IRM) is the ability to determinate the direction, if not the location, of the target object in which resistivity has been induced and now subject to measurement. This directionality makes it possible to determine the location of various objects in which the resistivity has been induced. A customary method of locating the source, or at least ascertaining the direction of the induced signal, is to utilize multiple antennas or signal receiving devises. Measuring the signal from multiple locations provides multiple references points for determining the location based upon conventional coordinate systems or other known methods. Determining the location or the direction of an object in which resistivity signals are induced has provided significant challenges. Prior to the present invention, the utility of IRM in such applications has been severely limited.
SUMMARY OF THE INVENTION
[0007] The present invention utilizes Magnetic Antenna and Magnetic Lensing techniques to overcome the limitations that heretofore have prevented multiple measurement to be taken from separate locations. Simply stated, the method and apparatus of the present invention discloses creating phase changes in a pulsed or oscillating magnetic flux transmitted from a magnetic flux transmitter. The phase changes are created in a controlled manner by utilization of the magnetic phase coded permeability lensing effect. As the transmitted oscillating magnetic flux passes through differing sections of a magnetic antenna, the phase of the original oscillating flux is modified into multiple phases. These multiple phases are also oriented in different directions. Accordingly, a flux from a single source and having a single phase, is altered into multiple and easily distinguishable flux signals. Further, since the multiple flux signals can each be oriented in different directions by the magnetic lens effect, it is possible to utilize the different induced phases from one or more magnetic flux transmitter to induce responsive oscillating flux signals within the target object from one or more of known locations relative to one or more signal receiving devices. These results in multiple Induced Resistivity Measurements that can provide the location or, at a minimum, the direction of the target object from the separate signal receiving devise.
[0008] Further, the invention can be used to create phase changes in other energy signals, such as acoustic signals and the electric component of an electromagnetic wave.
[0009] Accordingly, it is an object of the present invention to provide a method and apparatus for transmitting an electromagnetic signal through materials having varying magnetic permeability, electrical conductivity, density or geometry to obtain phase changes in the signals that may be directionally oriented.
[0010] It is another object of the present invention to utilize one or more receiving devices to determine the location, as well as direction, of one or more electrically conductive objects within a geologic formation or other media surrounding the invention.
[0011] It is an object of the present invention to provide a method and apparatus for creating multiple and distinguishable signals from a single source and utilizing at least one such signal for locating objects.
[0012] It is another object of the invention to transmit electrical signals through materials having varying dielectric properties to obtain phase changes in the signal that may be directionally oriented.
[0013] It is yet another object of the invention to transmit acoustic signals through materials of varying densities to obtain phase changes in the signal that may be directionally oriented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention. These drawings, together with the general description of the invention given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention for resistivity measurements within a confined space of a hydrocarbon production well.
[0015] [0015]FIG. 1 illustrates a collar device attached to production tubing or drill pipe comprising distinct sections having differing permeability properties.
[0016] [0016]FIG. 1A illustrates a cross sectional view of the embodiment.
[0017] [0017]FIG. 2 illustrates another embodiment of the invention.
[0018] [0018]FIG. 2A illustrates a cross sectional view of the embodiment of FIG. 2.
[0019] [0019]FIG. 3 illustrates the varying magnetic permeability, dielectric or density of different sections of the invention.
[0020] [0020]FIG. 3A illustrates the relative arc segments of the different sections.
[0021] [0021]FIG. 3B illustrates the differing arcs within which signals from differing segments are emitted
[0022] [0022]FIG. 3C illustrates the directional orientation of differing signal fields emitted from the differing sections of one embodiment of the invention.
[0023] [0023]FIG. 3D illustrates the directional orientation of energy concentrations emitted from another embodiment of the invention.
[0024] [0024]FIG. 4 illustrates an embodiment wherein the generator of the multiple phase oriented signals located separate from the signal receiver on production well tubing.
[0025] [0025]FIG. 5 is a schematic drawing of some of the components utilized in some embodiments of the invention.
[0026] The above general description and the following detailed description are merely illustrative of the subject invention, and additional modes, advantages and particulars of this invention will be readily suggest to those skilled in the art without departing from the spirit and scope of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] The invention subject of this application utilizes one or more sources for generating an oscillating or pulsed energy sources such as an ac generated electromagnetic wave. The signal may be transmitted from the signal generator in a distinguishable phase. Subsequent transmission through media having differing properties can cause the signal to attenuate or shift in phase. Differing media will have differing effect on the energy signal. Transmission of light through differing media has well known results in attenuation, direction and phase. Of course the attenuation and phase change can differ with the frequency of the original signal. The differing phase change can be used in the present invention in a controlled manner with one or more generated signals transmitted through multiple media or material of known properties and oriented in a known configuration. The signals emitted from each material will have differing properties, particularly differing phase. Since the each differing material may have distinct orientation to the transmitter and to any signal receiving device(s), it may be possible to ascertain the location of an object responding to the various signals of differing phase. This directionality can be enhanced by controlled selection of material and the strength of signals transmitted into the material. In regard to the transmission of electromagnetic waves through magnetically permeable material, the refraction or change in direction of magnetic flux emitted through the material can be controlled by selectively modifying the relative magnetic permeability of the material. This technique is termed the “Magnetic Lensing”™ effect.
[0028] In the preferred embodiment of the invention subject of this application one or more sources may be utilized for generating magnetic flux. The flux can be generated utilizing a pulsed dc generated magnetic flux or an oscillating magnetic flux. The magnetic flux oscillates or pulses at a controlled frequency and phase.
[0029] This flux is engaged with a magnetic antenna comprised of electrically conductive and magnetically permeable material, e.g., a ferromagnetic metal. It will be appreciated that such material typically acts as a barrier to the transmission of electromagnetic energy or signals. These materials are termed herein as “EM barriers” or “barrier materials.” The present invention teaches use of barrier materials of differing permeability, conductivity and shape to construct a lensed magnetic antenna for emitting oscillating flux of differing phase and for directing or focusing oscillating magnetic flux in a controlled manner. These lensed magnetic antenna components (or “antenna”) can be arranged or configured in multiple designs in accordance with the particular application.
[0030] The antenna components can be configured in a “collar type” antenna shape around a pipe or similar object as illustrated in FIGS. 1, 1A, 2 and 2 A. The lensed magnetic antenna 360 can be made of multiple sections of differing material or like material of differing shape, e.g., thickness. It will be appreciated that the materials of differing thickness or composition will have differing net permeability and conductivity. As a result, the oscillating magnetic flux from the transmitter 300 will be both phase shifted and directed as the portions of flux signal are transmitted through differing segments of the lensed magnetic antenna. As the antenna components are also conductive, the oscillating magnetic flux will also induce eddy currents within the material. These eddy currents will also vary in phase and orientation.
[0031] [0031]FIG. 1 illustrates separate antenna segments 370 through 383 configured into a single collar shaped lensed magnetic antenna 360 . Separate portions of the oscillating flux emitted from transmitter 300 are transmitted outward through separate antenna segments in the manner indicated by vector 889 . The power supply, amplifiers, signal generator, or receiver comprising apparatus of the invention 500 are not shown. Means to partially saturate the permeable segments comprising the lensed magnetic antenna 360 are also not shown. It may be anticipated that the means to couple with the antenna may be required to reduce the permeability of at least some of the segments in order that the oscillating magnetic flux can couple and penetrate into the surface of the antenna 360 . This may require placement of one or more saturation coils, not shown, within the space 952 proximate to the transmitter 300 .
[0032] Although it is anticipated that the invention may be used in conjunction with an outer well casing (not shown) comprised of an EM barrier material and in which the production tubing 100 and antenna 360 are positioned, embodiments of the invention may include use of non-permeable casing material. In this or other embodiments, it may be deemed advantageous to place the saturation coil (not shown) or other components of the invention inside the annulus 116 of the production tube 100 .
[0033] [0033]FIG. 1A shows the arrangement of the oscillating magnetic flux transmitter 300 with the individual antenna segments, e.g., 374 , 377 , etc. It will be noted that each antenna segment is immediately adjacent to the transmitter 300 . It will be appreciated that a small gap or spacing (not shown) of a known thickness may be maintained between the transmitter 300 and the lensed magnetic antenna 360 .
[0034] [0034]FIG. 1A shows oscillating magnetic flux of a single phase transmitted from the transmitter 300 . Since the flux is transmitted through segments of the antenna 360 having differing permeability or thickness, the oscillating magnetic flux within each segment will experience differing phase shifts. This results in phase angles θ 1 and θ 2 . Alternatively, these antenna segments could be of uniform thickness but using different materials with different permeability values. The segments of differing material could be configured in a predetermined phase-coded pattern. This phase coded configuration could be related to a particular directional orientation. This directional orientation of phase shift could be used to mark or encode magnetic flux induced in a conductive target object. The properties of the received signals from the differing phased magnetic flux induced in the target object could provide information related to the location or direction of the object. Since targets also can change the phase of an EM wave, the spatial relationship of the phase-coded configuration would be important in determining the returning wave direction.
[0035] Further, the differing permeability of antenna segments will result in differing relative permeability, i.e., differing degrees of reduced permeability and degrees of magnetic saturation. Therefore, the magnetic flux may be directionally oriented as it is emitted from the surface of the individual segment. This is illustrated in FIG. 1A by the vector lines 289 and 292 not being normal to the outer surface of the respective segment.
[0036] It will be appreciated that a phase code configuration be utilized that will be distinctive from possible induced phase changes within the targets.
[0037] It will, of course, be beneficial to have knowledge of the expected target object. For example, an advancing waterfront contact target would be changing the EM phase in a different way than stationary targets.
[0038] In one embodiment of the invention, the varying permeability creating the selected lensing of the transmitted magnetic flux may be comprised of alternating sections of the coating over the lensed magnetic antenna 360 . Each segment will have selected permeability variations of one (e.g., stainless steel) and ten (a semi-saturated ferromagnetic material). The resulting signals into the media would be coded at the separation angle of the lens segments and shown in FIGS. 3B, 3C and 3 D.
[0039] [0039]FIG. 2 illustrates a differing configuration wherein the transmitter 300 is not adjacent to each separate lens segment of the antenna collar 360 . In contrast to FIG. 1 and 1 A, an oscillating magnetic flux signal from the transmitter 300 may pass through several differing segments of the antenna, e.g., 373 and 374 prior to being emitted from the antenna segment 375 in the altered phase and direction. This is shown in FIG. 2A by the path of signal vectors 281 , 283 , 284 , and 287 . It will be appreciated that FIGS. 1, 1A, 2 and 2 A do not show the means of the apparatus 500 for receiving a separate oscillating flux signal that may be generated from eddy currents induced within target objects from oscillating magnetic flux emitted from various segments, e.g. 373 , 374 and 375 , of the antenna collar 360 .
[0040] [0040]FIG. 3 illustrates the antenna segments 370 through 374 have differing magnetic permeability, shown as μ 0 -μ 4 respectively.
[0041] [0041]FIG. 3A illustrates the arc of out surface of each antenna segment. It will be appreciated that each arc, e.g., θ 1 θ 2 and θ 3 , are co-terminus and that there is no overlap.
[0042] [0042]FIG. 3B illustrates an arc of angle θ A within which a transmitted signal may be emitted from a particular antenna segment. It will be appreciated that the arc may also overlap with the arc of at least the next adjacent antenna segment. This is shown by the overlap of arc θ A4 of possible signal transmission from segment 374 with the possible transmission arc θ A3 from segment 373 . The direction and phase of emitted signals (not shown) provides a marker or coding as to the origin of the oscillating magnetic flux. An electrically conductive object located outside of the antenna collar 360 may be engaged with flux emitted from one or more antenna segments. Eddy currents may be generated within the object through well-understood electromechanical principles. The eddy currents and resulting magnetic flux will have properties characteristic of the phase and direction of the magnetic flux from the applicable antenna segment, e.g. 374 , 372 . . This will accordingly provide information regarding the location of the object or the media that is responding to the flux transmitted by the lensed magnetic antenna. The specific length and geometry of the arc will be a function of the permeability and conductivity of the antenna section, the degree that the relative permeability of the segment is reduced, the configuration of the lensing segments comprising the magnetic flux antenna, and the properties of eddy currents induced within the antenna segments.
[0043] [0043]FIG. 3C illustrates that the multiple segments, and associated differing permeability and conductivity may achieve the directional lensing of oscillating flux. It will be appreciated that the directional orientation or vector of flux, 286 and 287 , emitted from certain segments, 376 and 377 , will not be normal to the outer surface (“second surface”) of the respective segments of the antenna configuration. This can be contrasted to the vector 285 representing flux emitted from 385 . It will of course be appreciated that this directionality will be impacted or achieved in part by the properties of the eddy currents induced in the separate antenna segments. FIG. 3D also illustrates the directionality achieved in flux vectors 279 and 283 emitted from the differing antenna segments.
[0044] In some embodiments of the invention, it may be desired to place electrical insulating material (not shown) between antenna segments to reduce cross transmission of eddy currents.
[0045] [0045]FIG. 4 illustrates a configuration of the invention wherein a receiver device 580 is placed on the production tubing 100 at a location separate from the magnetic flux antenna 360 . The separation of the transmitter 300 and the receiver 580 may facilitate nulling of the direct transmission of signal. It is envisioned that the device may be used in conjunction with well casing 111 not comprising an EM barrier, e.g., stainless steel, etc.
[0046] The lens segments may vary in thickness, causing like permeable materials to create varying phase shifting in the transmitted oscillating flux through the lens at different points by different amounts. This phase shifting occurs because the permeable material absorbs oscillating flux in proportion to the permeability value of the material and its thickness. In two dimensions, this phenomenon is shown in FIG. 4.
[0047] [0047]FIG. 4A illustrates an alternate configuration wherein the receiver 580 is oriented around the entire outer diameter of the production tubing 100 . It will be appreciated that in other embodiments, the axis of the receiver may be located orthogonal to the axis of the transmitter 300 or antenna collar 360 . Further, multiple receivers may be utilized, each oriented in a specified manner to the antenna or transmitter and thereby providing multiple reference points for determining the location of target objects possessing electrically conductive properties with the area of interest. Examples can include the location of water or the water within a hydrocarbon reservoir. In yet other embodiments, multiple receivers may be configured with opposing or bucked direction of windings.
[0048] The varying conductivity and permeability of the different antenna segments will further impact the characteristics (phase, frequency or amplitude) of the oscillating flux emitted from the differing antenna segments. It will be appreciated that flux engaging the differing segments will induce eddy currents within the segment. As a result of the skin depth phenomena, the largest concentration of eddy currents will be at the surface of the segment most adjacent to the transmitter. However, increased transmission of magnetic flux will reduce the permeability of at least some portions of the segments, particularly in the area most adjacent to the transmitter. As the permeability is reduced the skin depth increases. At a point at which a portion of the segment is sufficiently saturated such that eddy currents are induced at the opposite surface of segments, the skin effect will again cause the eddy currents to extend along this second surface of the antenna segment.
[0049] [0049]FIG. 5 illustrates some of the components utilized in the oscillating magnetic flux embodiment of the invention. Such components include a power supply 560 , a signal generator 563 , transmitter 300 , receiver 580 , amplifier 564 , signal converter 581 and an output display 582 . Also show in a separate saturation flux generator 551 utilized to reduce the permeability of antenna segments.
[0050] Persons skilled in the technology will appreciate it after reading this application that available equipment and techniques for generating other forms of energy signals, such as acoustic signals, may be transmitted through various materials that may alter the phase and directional orientation of the signal. Further, that alteration of the phase and directionality from a single source may provide information concerning the location or direction of objects responding to impingement with one or more such distinguishable signals.
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The present invention relates to a method and apparatus for obtaining measurements of induced resistivity of objects from spaces such as within a down-hole hydrocarbon production well. The invention also relates to measuring the location or direction of objects based upon measured responses from objects engaged or impinges by one or more transmitted signals having different phase and directional orientation. The invention relates to generating at least one signal or wave and transmitting it through a plurality of different materials that may have varying properties of density, magnetic permeability and dielectric that may each emit a separate signal with altered phase and directional orientation. When used with electromagnetic signals, the resistivity of an object or media can provide useful information regarding the composition and the location of object or media. Such embodiments of the present invention utilize the principles of Magnetic Antenna™ and Magnetic Lensing™ to obtain information regarding the location and properties of the target object.
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FIELD OF THE INVENTION
This invention relates to shuttleless weaving looms of the double layer type in which weft inserters, and especially weft-inserting needles located at two different levels, introduce the weft threads into the two superposed sheds and withdraw them from these latter.
BACKGROUND OF THE INVENTION
In looms of this type, the invention is more particularly directed to the so-called "flying needle" looms in which the needles are guided within the shed solely by bearing within the dihedral angle constituted by the plane of the reed and the plane of the lower layer of warp threads.
Looms of the double layer type are employed either for doubling the output for the same rate of weft insertion or for forming two layers of velvet or plush fabric.
It has become apparent that, in the case of a double-layer loom employed for the purpose of doubling the output, the same rate of insertion as in a single-layer loom could not readily be attained since the trajectories of the needles located at two different levels were not absolutely identical and gave rise to difficulties in regard to the exchange of wefts between the entry needles and the exit needles.
In double-layer looms, it is already a known practice to choose the position of the heald eyes so as to ensure that the lower layers of the two sheds on which the needles rest are always substantially parallel to each other. In spite of this favorable geometrical arrangement, however, the needles are liable to be subjected to stresses which cause them to deviate from their ideal trajectories within the aforesaid dihedral angle during their displacement with the slay of the loom and especially when the reed is inclined.
SUMMARY OF THE INVENTION
The aim of the present invenion is to overcome this disadvantage and to permit the construction of a double-layer loom in which the two superposed needles of one pair of needles always remain naturally parallel to each other and at a constant distance from one another.
The invention is directed to a loom in which, in the bottom position of the lower layers, the center-lines of the segments of said two layers located between the rear end position, of the reed of the loom and its intermediate position corresponding to the beginning of introduction of the needles into the shed, both pass substantially through the pivotal axis of the slay of the loom.
A more complete understanding of the invention will be gained from the following detailed description and from the accompanying drawings in which a number of embodiments of the invention are shown by way of example but not in any limiting sense, and in which:
DESCRIPTION OF THE FIGURES OF THE DRAWING
FIG. 1 is a diagrammatic view showing the arrangement of the layers of warp threads in a conventional double-layer loom for velvet;
FIG. 2 is a part-sectional view of a double-layer loom which embodies the improvement in accordance with the invention;
FIG. 3 shows an alternative form of FIG. 2 in the case of a loom having an inclined reed.
DESCRIPTION OF PREFERRED EMBODIMENTS
In the diagram of FIG. 1, the reed is shown in a conventional velvet loom in the beating-up position Po, in the intermediate position P1, and in the rear position P2. The upper shed F1 is formed by the upper layer N1 and by the lower layer N2 whilst the lower shed F2 is formed by the upper layer N'1 and by the lower layer N'2. The lower layer N2 and the upper layer N'1 are substantially parallel and the yarn (not shown) which is intended to form the velvet pile is interposed between these two layers in order to form two woven fabrics T1-T2 which are joined together by the pile threads, these latter being subsequently cut so as to form two separate velvet layers V1-V2.
There is shown at A1-A2 and B1-B2 the position of the upper and lower needles in the two positions P2-P1 of the reed. It is clearly apparent that the relative distance of a lower needle and of an upper needle will not be constant and on the other hand that the distance from the needles to the point of articulation 0 of the reed will not be constant. In the case of a loom in which guide means are not provided within the shed, this will subject the needles to stresses which have an adverse effect on the correct exchange of the weft thread between the entry needle and the exit needle.
In the double-shed weaving loom in accordance with the invention which is shown only in part in FIG. 2, there is shown the upper portion 2 of the slay which is mounted on swords 4. Said swords are pivoted about a shaft 6 having a center 0, said shaft 6 being supported by the frame of the loom. The movement of oscillation of the slay is controlled by a crankshaft (not shown) which actuates lugs 8.
By means of a slay cap (not shown), the slay 2 supports a reed 10 so designed as to have a height which is sufficient to receive two superposed sheds.
The lower layer 12 and the upper layer 14 of the lower shed 18 are positioned by the bottom edge C2 of the breast beam 20 and by heald eyes such as those designated by the references 22-24 and controlled by the harnesses which are not shown in the drawings and are employed for forming the shed.
The lower layer 26 and the upper layer 28 of the upper shed 30 are positioned by the top edge C1 of the breast beam 20 and by heald eyes 32-34.
The two pieces of fabric produced by the loom are indicated at 36 and 38 and the needle of the lower shed and the needle of the upper shed are designated respectively by the references 40 and 42.
The reed 10 in the beating-up position is shown in chain-dotted lines and designated by the reference 10 0 . In the intermediate starting position of the needles, the reed is indicated at 10 1 whilst the reed is shown in full lines and designated by the reference 10 2 at the rear dead point. In the intermediate position 10 1 of the reed, the needles are shown in chain-dotted lines and designated by the references 40 1 and 42 1 . The vertex of the dihedral angles formed by the plane of the read in its positions 10 2 -10 1 and by the planes of the layers 12 and 26 (the guiding of the needles being ensured by means of said dihedral angles) is indicated by the points A 1 -A 2 and B 1 -B 2 .
The position of the heald eyes 22-24-32-34 and the relative displacement of the harnesses which support the healds are chosen so as to ensure that the angle θ of maximum opening of the sheds is sufficient for the introduction and withdrawal of the needles and of the wefts.
In accordance with the embodiment illustrated in FIG. 2, the position of the eyes is also chosen so as to ensure that the lower layer 26 of the upper shed and the upper layer 14 of the lower shed interpenetrate. The intersection of these two layers must take place along a line which is always located behind the reed in its rear position 10 2 or in an extreme case as illustrated in FIG. 2, in the plane of the reed or in other words substantially at the point A 1 in FIG. 2 so as to ensure that the upper layer 14 of the lower shed does not interfere with the trajectory of the upper needle 42.
When the reed oscillates between the positions 10 1 -10 2 -10 1 , the lower needle 40 slides over the segment A 2 -B 2 of the lower layer 12 whilst the upper needle 42 slides over the segment A 1 -B 1 of the upper layer 26.
In accordance with the invention, the location and relative displacement of the eyes 22-24-32-34 are chosen so as to ensure that the center-lines M normal to the two segments A 1 -B 1 and A 2 -B 2 pass substantially through the center 0 of articulation of the reed.
By virtue of this arrangement, the relative distance D of the needles remains constant throughout the trajectory of this latter and the same applies to the respective distance between the needles and the center 0 of articulation of the reed. In consequence, the wholly rectilinear trajectory of the two parallel needles can be maintained throughout the travel of these latter through the sheds and this permits correct exchange of the weft thread even at high insertion rates.
In the case illustrated in FIG. 2, the plane of the reed 10 passes through the pivotal axis 0 or, in other words, the reed is "straight" on the sley and not inclined. In this particular case, the segments A 2 -B 2 and A 1 -B 1 are parallel and the center-lines M of these latter coincide. In other words, the lower layers 12 and 26 of the two sheds are parallel and located at a distance D from each other which is equal to the constant spacing of the two needles 40-42.
In practice, it is often advantageous to ensure that the reed is "inclined" for the operation of the loom.
A case of this type is illustrated in FIG. 3 in which the same reference numerals as in FIG. 2 have been adopted. It is apparent that the plane of the reed 10 does not pass through the articulation 0 since the reed is inclined in the forward direction.
In accordance with the invention, the center-line M 1 normal to the segment A 1 -B 1 of the layer 26 and the center-line M 2 normal to the segment A 2 -B 2 of the layer 12 are concurrent in the center of articulation 0 of the slay but these two centerlines do not coincide as in the case of FIG. 2 by reason of the inclination of the reed with respect to the radius R.
Since these two center-lines do not coincide, the segments A 1 -B 1 and A 2 -B 2 are not parallel. In other words, the lower layers 12 and 26 are also not exactly parallel, in contrast to the particular case of FIG. 2. It is also seen in FIG. 3 that interpenetration of the layers is not essential.
In accordance with the invention and as in the case of FIG. 2, the distance D' between the lower and upper needles 40-42 remains constant and the same applies to the distance between each needle and the center articulation 0.
In accordance with usual practice, the reed can comprise a bottom needle board 44, this board being intended to travel over the segment A 2 -B 2 or more precisely the circular arc A 2 -B 2 while being applied with slight friction against the layer. It can therefore be stated that said needle board defines the geometrical construction which is favorable to good guiding of the needles even if the heald eyes 22-24 do not exactly define this construction.
Similarly, in the case of the layer 26 of the upper shed, provision can be made (as described in French patent Application No. 75 18199 filed on June 11, 1975 in the name of the present Applicant) for an ancillary board placed immediately behind the reed and constituted, for example, by a wire or rod stretched transversely with respect to the layer.
It may clearly be difficult in practice to determine on the layers of threads which have a certain mobility and certain elasticity, whether the center-line of a segment passes substantially through a pivotal axis. For this reason it is easier to ascertain both with a straight reed and with an inclined reed whether, in positions 10 1 and 10 2 of the reed, the points A 2 and B 2 of passage of the layers through the reed are in fact located at the same height on the reed and whether the same applies to the points A 1 and B 1 . To this end, it is possible, for example, to stretch two threads over the reed and to check whether they are in fact in contact respectively with the layers 12 and 26 at the points A 2 -B 2 and A 1 -B 1 .
As can readily be understood, the invention is not limited to the embodiments described and illustrated and, depending on the applications which may be contemplated, can extend to a large number of alternative forms which are within the capacity of those versed in the art without thereby departing either from the scope or the spirit of the invention.
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In a shuttleless weaving loom of the double layer type, the position of the heald eyes and the relative displacement of the harness shafts which carry the eyes are such that, in the bottom position of the lower layers, the center-lines of the segments of the two layers, which are located between the rearmost position of the weaving loom and its intermediate position corresponding to the beginning of introduction of the weft threads into the sheds, both pass substantially through the pivotal axis of the reed.
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BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to improvements in feeders for headed fasteners such as rivets, and to riveting machines incorporating such feeders.
(2) Brief Description of the Prior Art
Our Australian Pat. Nos. 488189 and 504196 (and corresponding British Pat. Nos. 1,502,475 and 1,538,027 respectively) disclose methods of and apparatus for riveting where the rivets punch their own holes through the work pieces to be joined.
U.S. Pat. No. 4,410,103 a method and apparatus for sequentially feeding rivets to such riveting machines from a tape charged with rivets according to the method and apparatus disclosed in U.S. Pat. No. 4,404,742.
These riveting machines and feeders for directing rivets to them have been found to be efficient and generally satisfactory in use, but they are fairly bulky and expensive to manufacture and install.
SUMMARY OF THE PRESENT INVENTION
The present invention has been devised with the general object of providing a feeder for rivets or other headed fasteners which is particularly simple, economical and compact, which is applicable to a readily portable riveting machine, and which is very convenient to use and efficient and positive in action.
With the foregoing and other objects in view, the invention resides broadly in a feeder for sequentially feeding, from a flexible carrier tape, headed fasteners driven therethrough in equally spaced intervals, including:
a guide bush,
a delivery passage through the guide bush,
a guide passage in the guide bush for guiding the fasteners in sequence to the delivery passage,
a plunger mounted for advance into and retraction from the delivery passage,
a punch at the leading end of the plunger,
means for advancing the plunger to drive the punch through the tape, expelling a fastener therefrom into the delivery passage,
means for retracting the plunger to withdraw the puch from the carrier tape,
an actuator oscillatably mounted in the guide bush for movement by the advancing plunger from an advanced position to a retracted position,
actuator return means for removing the actuator from its retracted position to its advanced position upon the retraction of the plunger, and
fastener engaging means on the actuator adapted, with successive oscillations of the actuator, to engage the advance sequentially towards the discharge passage, the fasteners of the carrier tape.
The invention further resides in a rivet setting machine incorporating the feeder set out above.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a partly broken-away side elevational view of a rivet setter incorporating a rivet feeder according to the invention,
FIG. 2 is a sectional view, to larger scale, along side 2--2 in FIG. 1, showing the device prior to ejection and setting of a rivet,
FIG. 3 is a sectional view showing a rivet fed and set in a workpiece,
FIG. 4 is a plan view of the actuator of the device shown in FIGS. 1, 2 and 3,
FIG. 5 is a side elevational view of the actuator,
FIG. 6 is a view of the actuator from below,
FIG. 7 is an end view of the actuator, and
FIG. 8 is a sectional view of part of a rivet setter according to a modification of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The rivet setter includes a C-frame 10 having upper and lower jaws 11 and 12 rigidly interconnected by a tension post 13 and a compression post 14, both of which are interchangeable with others of different lengths for adjustment of the frame to suit different requirements. The upper jaw 11 is provided with a cylindrical clamp collar 15, the lower jaw with a coaxial cylindrical holder 16 for a rivet upsetting die 18, which is secured by a screw 19 and interchangeable with others of different axial length.
A hydraulic cylinder 20 is secured in axially adjustable manner in the clamp collar 15, being formed with a circumferential shoulder to bear on the top of the clamp collar, a spacer collar 21 then being fitted on the hydraulic cylinder from below and secured by a lock nut 22 screwed onto the bottom part of the cylinder. By fitting the spacer collar above, instead of below, the clamp collar, or by using shorter spacer collars above and below the clamp collar, the hydraulic cylinder may be adjusted axially.
The top of the hydraulic cylinder is closed by a plug 23, an elbow 24 having one arm engaged in a threaded axial hole through the plug having its other arm connected to a hydraulic pressure line (not shown) from any suitable preferably portable source (not shown) of hydraulic fluid under pressure.
A hollow plunger 25 is coaxially slidable in the cylinder 20, a bush 26 slidable in the cylinder being secured about its upper part, between a circumferential shoulder 27 about the plunger and an annular seal 28. The lower part of the plunger 25 is slidable in a guide bush 29 which itself is slidable in the cylinder 20, the slidable movement of the plunger relative to the guide bush being restricted by a key 30 screwed into the plunger and engaging in a longitudinal slot 31 in the guide bush 29.
The slidable extension of the plunger 25 in the cylinder 20 is limited by a stop ring 32 seated in an annular groove in the wall of the cylinder and against which the shoulder 27 of the plunger is brought if the normal stroke of the plunger should be accidentally exceeded.
The plunger 25 is biased to its retracted position, as shown in FIGS. 1 and 2, by a helical tension return spring 33 anchored at one end to a diametral pin 34 through the plug 23 and extending down into the axial bore of the plunger, the other end of the spring secured by a screw 35 engaged in a threaded plug 36 in the plunger bore.
A punch 37, having one end held by a set-screw 38 in the plunger bore, extends coaxially from the plunger.
The guide bush 29 is enlarged in diameter below the cylinder 20 to form a guide bush head 39 which limits the retraction of the guide bush into the cylinder and is formed with a transverse opening 40 within which is located an actuator 41, as shown in FIGS. 2 to 6 or alternatively a modifed form of actuator 41a, as shown in FIG. 8, both embodiments being hereinafter described.
The guide bush 29 is urged to fully extended position relative to the plunger 25 by a helical compression stripper spring 42 located about the plunger 25 between the plunger shoulder 27 and the inner end of the guide bush 29, and passing freely through the stop ring 32.
Rivets 43 to be fed and set by the device are carried, in equally spaced arrangement, by a carrier tape 44 of a resiliently flexible material, the rivets being held firmly in centrally aligned arrangement in the tape by driven through undersize holes therein. The tape 44 carrying the rivets 43 is fed to the device through a feed tube 45 held to one side of the cylinder 20, above the clamp collar 15, by a clamp 46. This clamp also holds, at the opposite side of the cylinder 20, an outer tape discharge tube 47 within which there is telescopically slidable the upper part of an inner tape discharge tube 48, the lower part of which is releasably secured to the guide bush head 39 by a bracket 49 held by screws (not shown) to the upper part of the guide bush head, and by screws 50 engaged in the lower part of the guide bush head. The slidable engagement of the inner tape discharge tube, fixed to the guide bush head, in the outer tape discharge tube, which is fixed to the hydraulic cylinder, restrains the guide bush and associated parts from rotation relative to the cylinder.
An axial hole formed from the bottom of the guide bush head 39 into the transverse passage 40 accepts a cap nut 51 which has a bore or rivet delivery passage 52, the upper part of which is downwardly tapering, aligned coaxially with the punch 37. A rivet passage 53 leads radially into the rivet delivery passage 52 from a side of the guide bush head 39 and the upper part of the cap nut. A number of steel balls 54 in radial holes in the cap nut protrude into the rivet delivery passage 52, and are urged to inmost position by a resilient band 55 in a circumferential groove about the cap nut and intersecting the radial holes.
Referring now to FIGS. 1 to 7 inclusive, the actuator 41 has a body 56 oscillatable about pivot pins 57 fixed in opposed holes 57a in the guide bush head 39. The actuator body is formed with a passage 58 through which the punch 37 passes freely whether the actuator is in its advanced or tilted position as shown in FIG. 2, or in its retracted or non-tilted position as shown in FIG. 3. When the plunger 25 and punch 37, and the guide bush 29, are in their fully retracted position (FIG. 2) the actuator 41 is held in its tilted position by a double torsion spring 59 secured at one end, by a screw 60 and plate 61, to one side of the actuator body 56, the spring at its other end 62 being shaped to press slidably against the plunger 37. When the actuator is so tilted, its body at one end, abuts against a shoulder 63 within the guide bush head 39.
When the plunger 31 is extended, it strikes the top of the tilted actuator body forcing it, against the action of the torsion spring 59, to its non-tilted or retracted position as shown in FIG. 3.
A double-pawl spring 64 is fixed, by a screw 65, in a recess 66 in the top of the actuator body, the two arms of this double-pawl being V-shaped and spread apart at the angles, their free ends being brought close together.
In use, the plunger 31 and punch 37, and the guide bush 39, are initially fully retracted as shown in FIG. 2, the actuator 41 being in its advanced or tilted position. The leading end of the carrier tape 44, which is free of rivets for some distance, is carried down from the feed tube 45, between the spread arms of the double-pawl 64, under the bottom of the actuator 41 and up into the inner tape discharge tube 48. As shown particularly in FIG. 8, the carrier tape 44 has raised side edges, and the actuator 41 is recessed to receive these and also to accept the heads of the rivets 43. The tape is drawn under the actuator until the leading rivet 43 is moved through the rivet passage 53 and brought to rest substantially coaxially in the rivet delivery passage 52, directly under and coaxial with the punch 37.
A work piece 67 (FIG. 3) to be riveted is located upon the die 18 and hydraulic fluid under pressure is introduced to the cylinder 20. Thereupon the plunger is extended against the action of its return spring 33 and, at the same time, the guide bush is extended by the action of the stripper spring 42 until the cap nut 51 is brought down onto the work piece 67. Although the guide bush 29 is thus restrained against further movement, the plunger 25 and punch 27 are then further extended, against the action now of the stripper spring 42 as well as the return spring 33. The punch 37 therefore drives the leading rivet through the tape 44 and the rivet delivery passage 52, in which it is correctly aligned by the balls 54, and through the work piece 67 to be deformed by the upsetting die 18. After the punch 37 has penetrated the carrier tape 44 from which it has driven the leading rivet, and therefore holds the tape against movement, the plunger 25 strikes the top of the actuator 40, turning it, against the action of its double torsion spring 59, from its tilted to its nontilted or retracted position. The double spring pawl 64, the ends of which previously engaged the second rivet, as shown in FIG. 2, is thus retracted past, and for some distance beyond, the third rivet, as shown in FIG. 3.
The hydraulic pressure in the cylinder 20 is now relieved so that the plunger 25 is retracted by its return spring 33, first moving clear of the actuator 40, then becoming disengaged from the carrier tape 44, and then, because of the engagement of the key 30 in the slot 31, moving the guide bush 29 to its retracted position so that the actuator 40 can advance to its tilted position under the action of its spring 59. As the actuator so turns, its double pawl 64 engages the third rivet and moves it, and the carrier tape 44, so that the previously second rivet is moved through the rivet passage 53 into the rivet delivery passage 52, aligned coaxially under the retracted punch 37.
The working parts of the riveting machine may be quickly and easily removed from the C-frame 10. The parts are so made and arranged that by detaching the pawl 64 from the actuator 41, and the inner tape discharge tube 48 from the guide bush head 39, and unscrewing the lock nut 22, the cylinder 20 and associated parts may be withdrawn through the clamp collar 15.
Referring now to FIG. 8, the modified actuator 41a is formed with ratchet teeth 70 for engaging the heads of the rivets 43. Instead of the pawl 64 shown in FIGS. 1 to 6 for engaging the rivet shanks, there is secured to the body of the actuator 41a a double guide spring 71 the ends of which bear against the carrier tape 44 to both sides of a rivet 43 to cause the head of that rivet, or the heads of more than one rivet, firmly into engagement with one or more of the actuator teeth 70.
Feeders for headed fasteners, instead of being applied to a riveting machine as described and illustrated, may be used for ejecting rivets from a carrier tape, one at a time, into a feed tube, for example, or for bringing screws in sequence to a position to be driven by a motor-operated screwdriver.
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A feeder for headed fasteners, such as rivets (43), driven at equal intervals through a tape (44), is applicable to a riveting machine (10) and includes a plunger (25) advanced and retracted through a guide bush (29) and with a punch (37) at its leading end. When the plunger (25) advances the punch (37) is driven through a delivery passage in the guide bush head (39). A guide tube (45) leads the tape (44) to bring fasteners (43) in sequence into the rivet delivery passage (52). An actuator (56), oscillatable in the guide bush (39), is moved to retracted position by the advancing plunger (25), and is automatically returned to advanced position when the plunger (25) retracts. Fastener engaging means (64) on the actuator (56) act, with each retraction and advance of the actuator (56), to engage a fastener (43) and move it towards the delivery passage from which the leading fastener (43) is driven by the advancing punch (37) which, penetrating the tape (44) holds the tape (44) against movement while the actuator (56) is moved to its retracted position.
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FIELD OF THE INVENTION
[0001] The present invention relates to the field of data decoding. More particularly, the invention relates to a method for efficiently decoding a number of data channels.
BACKGROUND OF THE INVENTION
[0002] As of today, TV channels, or digital media content services, are presently communicated by: land-based radio-type broadcast transmissions, cable network transmissions or space satellite transmissions. In order to limit reception to registered subscribers, it is common practice for content providers to scramble, i,e. encode, their transmissions and to require their registered customers to use a special set-top control box which uses deciphering techniques to decode the received signals. The term of encode refers hereinafter to include scrambling, ciphering or any other process of encrypting data, similarly, the term of decode refers hereinafter to include descrambling, deciphering or any other process of decrypting data.
[0003] In order to efficiently encode digital media contents, each media content is divided into data blocks where each block is encoded using a cipher key. After encoding, the encoded media contents are sent to the customers' set-top box. The encoding technique may be a symmetric encoding technique such as the Data Encryption Standard (DES). In symmetric encoding, the cipher key used for encoding data is the same key used for decoding the data. Therefore, the encoded media contents, i.e. the encoded blocks, are typically supplied with their corresponding encoding/decoding cipher key to the customer's set-top box for decoding. Typically, the supplied cipher key itself is also encrypted in order to eliminate content theft. In many cases, the provider of the media contents first encodes the media contents, using one general cipher key, after which he encodes the general cipher key with a customer-specific cipher key for each of his customers. The general cipher key may be decrypted only in the customer's setup box which has a specific decrypting key stored within. Thus the encoded media contents may be broadcasted over open transmission channels, such as stated before, where only the registered customers are able to view the media contents.
[0004] It is an object of the present invention to provide a method for efficiently encoding/decoding a number of data blocks.
[0005] It is another object of the present invention to provide a reduced hardware system for efficiently encoding/decoding a number of data channels.
[0006] Other objects and advantages of the invention will become apparent as the description proceeds.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a method for efficiently decoding a plurality of ciphertexts comprising the steps of: (a) receiving at least one cipher key associated with said ciphertexts; (b) expanding said at least one cipher key for producing its corresponding subkeys; (c) storing said subkeys in a memory; (d) loading said subkeys from said memory; and (e) decoding said ciphertexts using said loaded subkeys.
[0008] Preferably, the plurality of ciphertexts is received from different data channels.
[0009] The present invention relates to a system for efficiently decoding a plurality of ciphertexts comprising: (a) a processing unit for expanding at least one cipher key into subkeys; (b) memory for storing said subkeys; and (c) a plurality of cipher block decoders which receive said subkeys from said memory and decode said ciphertexts using said subkeys.
[0010] In one embodiment, the processing unit is implemented in hardware.
[0011] In another embodiment, the processing unit is implemented in software running on a general processing unit.
[0012] Preferably, the processing unit is used for encoding and decoding.
[0013] In one embodiment, the memory may store keys from different standards.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In the drawings:
[0015] FIG. 1 is a schematic diagram depicting the operation of a prior art block cipher and key expansion.
[0016] FIG. 2 depicts an example of a DES key expansion for producing the corresponding subkeys.
[0017] FIG. 3 discloses the table PC- 1 and PC- 2 of the rearranging order of the cipher key.
[0018] FIG. 4 is a schematic diagram depicting the method of the invention according to one embodiment.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] A block cipher is a symmetric key cipher which operates on fixed-length groups of bits, termed blocks, with an unvarying transformation. When encoding, a block cipher might take, for example, a 128-bit block of plaintext as input, and output a corresponding 128-bit block of ciphertext. The exact transformation is controlled using a cipher key. Prior art block ciphers, which are also referred as substitution-permutation networks, involve a sequential repetition of an internal function called round function. The round function uses in each repetition a derivative of the cipher key known as a subkey for encoding. The basic idea of the round function is to build a complex encoding scheme by composing several simple operations which offer complementary, but individually insufficient, protection. Basic operations include transpositions, translations (e.g., XOR) and linear transformations, arithmetic operations, modular multiplication, and simple substitutions and permutation (non-linear transformations). Decoding is similar to encoding where, in this example; a 128-bit block of ciphertext is decoded using the cipher key, for yielding the original 128-bit block of plaintext. The full description of the encoding and decoding methods can be found in the Federal Information Processing Standards Publication 46-3, Oct. 25, 1999 of the “DATA ENCRYPTION STANDARD” (DES). Other descriptions of the encoding and decoding methods are also present in the Federal Information Processing Standards Publication 197, Nov. 26, 2001 of the “ADVANCED ENCRYPTION STANDARD” (AES), the ISO/IEC standard 9979 (9)—otherwise known as Mulit2, the 4C Entity, LLC. Jan. 17, 2003—C2, X. Lai, J. L. Massey and S. Murphy, Markov ciphers and differential cryptanalysis, Advances in Cryptology—Eurocrypt '91, Springer-Verlag (1992), 17-38—IDEA, and Block encryption algorithm with data-dependent rotations—such as U.S. Pat. No. 5,724,428.
[0020] The desirable characteristics for a block cipher include: (a) that each bit of the ciphertext should depend on all bits of the cipher key and all bits of the plaintext, (b) that there should be no statistical relationship evident between the plaintext and the ciphertext, (c) that altering any single plaintext or cipher key bit should alter each ciphertext bit with probability of 0.5, and (d) that altering a ciphertext bit should result in an unpredictable change to the recovered plaintext.
[0021] FIG. 1 is a schematic diagram depicting the operation of a prior art block cipher 20 and key expansion. The terms key expansion and key expanding are meant to include hereinafter key schedule, key manipulation, or any other process of deriving a subkey or subkeys from a cipher key. The method of Key expansion will also be discussed in relations to FIG. 2 . In prior art systems the key expansion and the block cipher 20 are each performed by dedicated hardware circuits. At first the cipher key 10 is expanded by the key expansion process for producing the first subkey K 1 100 . The subkey K 1 100 is then fed into round function F 1 200 for encoding. Thus the key expansion process continues expanding the subkey K 1 100 for yielding the next subkey K 2 110 , which is fed to the next round of encoding of round function F 2 210 . Thus both processes may continue in parallel; where the key expansion process yields a new subkey each round and the cipher block process continues to encode each round with the round function and the new subkey, until the last key K N 120 is fed into the last round function F N 220 and the round function F N 220 completes the encoding, effectively producing the ciphertext. The decoding process is similar to the described above encoding process, where a ciphertext is received together with the cipher key and the ciphertext is decoded into plaintext using the inverse round functions and the subkeys derived from the expanded received cipher key. Nevertheless, since in the key expansion process each subsequent subkey is based on a former subkey/key, the key expansion circuit can process each subkey only after processing a former subkey/key. Therefore, typically in the prior art systems, there is a dedicated hardware circuit for expanding the cipher key and producing the subsequent subkeys for each round function, although the dedicated key expansion circuit requires much less processing power and time than the circuit processing the round functions.
[0022] FIG. 2 depicts an example of a DES key expansion for producing the corresponding subkeys. The DES is a block cipher which takes a fixed-length string of plaintext bits and transforms it through a series of complicated operations into a ciphertext string of the same length. In the case of DES, the string length is 64 bits. DES also uses a cipher key to customize the transformation, so that decoding can only be performed by those who know the particular cipher key used to encode. The cipher key ostensibly consists of 64 bits; however, only 56 of these are actually used by the algorithm. Eight bits are used solely for checking parity, and are thereafter discarded. As shown in FIG. 2 , the cipher key 10 , as may be received with the ciphertext, is first rearranged according to a Permuted Choice table labeled PC- 1 shown in FIG. 3 . As shown in FIG. 3 the table PC- 1 depicts the rearrangement order of the 64 bits in 2 parts C n and D n . The first part is labeled by C 0 and processed apart from the second part labeled D 0 . The first part C 0 and the second part D 0 are each left shifted by 1, according to the standard, and may be permuted together according to PC- 2 depicted in FIG. 3 for yielding the first subkey K 1 . The process may continue with both parts of key as shown in FIG. 2 until all the required subkeys are produced, according to the standard.
[0023] FIG. 4 is a schematic diagram depicting the method of the invention according to one embodiment. At first the cipher key 10 undergoes the key expansion process 60 in order to produce the corresponding subkeys. The key expansion process 60 may be preformed by any processing unit capable of expanding a cipher key according to any one of the cipher block standards, such as DES, AES, multi2, C2, IDEA, etc. The produced subkeys such as subkeys 100 , 110 , and 120 are stored in memory 50 . Memory 50 may be any kind of repository used for storing data such as FLASH, EPROM, RAM, etc. The produced subkeys may then be loaded from memory 50 and used for decoding their corresponding cipher block such as cipher block 20 . After the first cipher key 10 has been expanded, the processing unit, used for expanding the key 10 , may be used for expanding a new cipher key into a new set of subkeys. The new set of subkeys is also stored in memory 50 from where they may be loaded and used for decoding their corresponding cipher block such as cipher block 30 . The processing unit may continue expanding more cipher keys such as the cipher key corresponding to the cipher block 40 , in parallel to the continual processing of the other cipher blocks which use the already produced subkeys. In one of the embodiments the processing unit 60 is capable of expanding 4 cipher keys into 4 sets of subkeys in less time than required to decode each of the cipher blocks. In this embodiment only one key expansion processing unit is implemented with 4 dedicated hardware circuits for block ciphering. In other embodiments, processing unit 60 is capable of expanding more (or less) than 4 cipher keys in less time than required to decode each of the cipher blocks. In one of the embodiments the set of subkeys stored in memory 50 which correspond to a certain cipher key may be reloaded and reused for decoding another cipher block having the same corresponding cipher key. In this embodiment each set of subkeys may be stored for a certain amount of time or a certain amount of machine cycles or any other condition before being erased. Thus instead of designing a hardware circuit for manipulating a deciphering key dedicated for each cipher block decoder, one such processing unit may service a plurality, i.e. at least 2, of incoming cipher blocks, effectively saving precious hardware circuit space and time. The encoding process is similar to the described above decoding process, where one processing unit may service a number encoding cipher blocks.
[0024] In one of the embodiments the same processing unit and memory may be used for encoding and decoding.
[0025] In one of the embodiments the same memory may be used for storing subkeys produced by different standards. The memory may be connected to a plurality of processing units, where each processing unit performs according to one of the standards. For example a memory may be connected to a processing unit, which expands keys according to the DES standard, and to a processing unit which expands keys according to the AES standard.
[0026] In one of the embodiments the key expansion processing unit is implemented in hardware. In one embodiment the key expansion processing unit is implemented in a time relaxed hardware design as opposed to the time strict hardware design of the hardware circuits decoding the cipher blocks. In another embodiment the key expansion processing unit may be implemented in software processed by a general processing unit.
[0027] In one of the embodiments the key expansion processing unit and a number of cipher block decoders are implemented together, where each cipher block decoder decodes an incoming data channel in a continual manner, cipher block after cipher block, and the key expansion processing unit services all the cipher blocks decoders in turns. In one of the embodiments the data channels are media channels.
[0028] For the sake of brevity an example is set forth for depicting the process of a key expansion processing unit according to an embodiment of the invention. In this example many media channels are received in parallel. If 1 full HD channel is transmitted at a rate of 8 MB/s video together with two audio channels each 384 KB/s and additional information, then the total data rate can be assumed at around 9 MB/s. An AES decoder can decode 128 bits in a cipher block, meaning that 74K AES cipher blocks are required to be processed each second in order to decode one channel (9M/128=9*2 20 /2 7 =9*2 13 ˜74K AES cipher blocks per second). If for example each AES cipher block round requires 500 machine cycles, then the total machine cycles required for decoding one full HD channel is 37M machine cycles per second. Since the cipher blocks are required to be encoded in tandem, in order to decode 1 HD channel without causing delays requires the cipher block decoders to process in a rate at least 40 MHz. In this example the key expansion circuit requires an estimated 4K machine cycles for expanding one cipher key into a set of subkeys. Thus the key expansion processing unit may expand one key in a 0.0001 sec, in a 40 MHz rate, effectively allowing the key expansion processing unit to expand many keys for many AES cipher blocks. Since several blocks share the same key, it is apparent that even if multiple AES cipher block decoders are required in order to support this scenario of receiving and displaying multiple HD channels only one key expansion engine is required, which can service these AES cipher block decoders.
[0029] While some embodiments of the invention have been described by way of illustration, it will be apparent that the invention can be carried into practice with many modifications, variations and adaptations, and with the use of numerous equivalents or alternative solutions that are within the scope of persons skilled in the art, without departing from the invention or exceeding the scope of claims.
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The present invention relates to a method for efficiently decoding a plurality of ciphertexts comprising the steps of: (a) receiving at least one cipher key associated with said ciphertexts; (b) expanding said at least one cipher key for producing its corresponding subkeys; (c) storing said subkeys in a memory; (d) loading said subkeys from said memory; and (e) decoding said ciphertexts using said loaded subkeys.
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TECHNICAL FIELD
[0001] This application is a continuation (and claims the benefit of priority under 35 USC 120) of U.S. application Ser. No. 13/751,891, filed Jan. 28, 2013; which is a continuation of U.S. application Ser. No. 12/791,691, filed Jun. 1, 2010, now U.S. Pat. No. 8,359,843; which is a continuation of U.S. application Ser. No. 11/557,431, filed Nov. 7, 2006, now U.S. Pat. No. 7,726,120; which is a continuation of U.S. application Ser. No. 09/862,973, filed May 22, 2001, now U.S. Pat. No. 7,311,066; which claims priority from U.S. provisional application Ser. No. 60/206,050, filed May 22, 2000. The disclosures of the prior applications are considered part of (and incorporated in) the disclosure of this application.
[0002] This invention relates to cooling engine exhaust manifolds and related components, and more particularly to controlling the temperature of engine exhaust components and the exhaust gasses flowing through them.
BACKGROUND
[0003] The exhaust gasses flowing through an exhaust gas manifold of an internal combustion engine are typically very hot, and the exhaust manifold itself may reach very high surface temperatures. To keep the outer surface temperature of the exhaust manifold down for safety reasons, some exhaust manifolds are water cooled, meaning that they contain inner passages through which cooling water flows during engine operation or that they are placed within jackets with cooling water flowing directly across the outer surface of the manifold. Indeed, there are some regulations requiring that exhaust manifolds be provided with cooling jackets for particular applications, such as for marine vessel inspections.
SUMMARY
[0004] In one aspect, the invention features a cooling jacket having internal passages for flowing water or other coolant through the jacket to moderate jacket temperature. The jacket attaches to the engine cylinder head to enclose and cool the exhaust manifold of the engine, thereby moderating the temperature of the exhaust gas flowing through the manifold and blocking the outer surface of the manifold from unwanted contact with nearby objects or personnel. As the coolant flows through internal passages in the manifold rather than through or across the exhaust manifold, the coolant never comes into contact with the manifold itself. Manifold cooling is achieved via radiant and convective heat transfer to the jacket when an air gap is provided between the outer surfaces of the manifold and the inner surfaces of the cooling jacket, or by conduction through an insulating material placed between the manifold and jacket. Among the various aspects of the invention are the cooling jacket so described, engines equipped with such cooling jackets, and methods of cooling engine exhaust manifolds by incorporating such jackets.
[0005] In some embodiments the cooling jacket defines a coolant inlet and a coolant outlet that are both separate from the exhaust stream. In some other cases, particularly applicable to marine engines, for example, coolant enters the jacket through a separate inlet but then joins the exhaust flow as the exhaust leaves the manifold, thereby further reducing exhaust gas temperature.
[0006] In another aspect, the invention features a liquid-cooled turbocharger disposed between a liquid-cooled exhaust manifold and a liquid-cooled exhaust elbow, such that manifold cooling fluid flowing to the elbow flows through and cools the housing containing the turbocharger. Preferably, for marine applications, for instance, the cooling fluid is injected into the exhaust stream downstream of the turbocharger, such as in the elbow. In some cases, the manifold cooling fluid flows through the exhaust manifold itself. In some other cases, the fluid cools the manifold by flowing through a channel within a jacket that surrounds the manifold, as discussed above.
[0007] In some embodiments, the manifold houses an exhaust conversion catalyst. The exhaust conversion catalyst is arranged within the exhaust stream, such that the exhaust flows through the catalyst, and is isolated from the liquid coolant, which flows around the catalyst. Preferably, the flow of liquid coolant joins the flow of exhaust downstream of the catalyst. In some embodiments, an insulating blanket is placed between the catalyst and the manifold housing to help to insulate the hot catalyst from the surrounding housing, thereby promoting exhaust conversion and avoiding excessive external surface temperatures. The blanket can, in some cases, also help to protect fragile catalysts from shock damage.
[0008] In another aspect of the invention, a liquid-cooled exhaust manifold houses an exhaust conversion catalyst arranged within the exhaust stream, such that the exhaust flows through the catalyst, and is isolated from the liquid coolant, which flows around the catalyst. The manifold is adapted to receive and join separate flows of exhaust gas and direct them through the catalyst. The manifold comprises a one-piece housing, preferably of cast metal, forming the internal exhaust flow passages and cavity for receiving the catalyst.
[0009] Some aspects of the invention can provide for the ready modification of engines to comply with exhaust manifold cooling requirements, without having to modify the exhaust manifold to either provide for internal cooling or withstand prolonged surface contact with a desired coolant. Furthermore, the temperature of the exhaust gas within the manifold can be maintained at a higher temperature than with normally cooled manifolds, given a maximum allowable exposed surface temperature, enabling more complete intra-manifold combustion and improving overall emissions. Among other advantages, some aspects of the invention help to maintain high exhaust temperatures, such as to promote exhaust catalytic conversion, for example, without producing undesirably high external surface temperatures.
[0010] 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
[0011] FIGS. 1A and 1B are front and back perspective views, respectively, of an exhaust manifold cooling jacket.
[0012] FIG. 2 is a side view of the cooling jacket, viewed from the side adjacent the engine.
[0013] FIG. 3 is an end view of the cooling jacket.
[0014] FIGS. 4 and 5 are cross-sectional views, taken along lines 4 - 4 and 5 - 5 , respectively, in FIG. 2 .
[0015] FIG. 6 is a cross-sectional view, taken along line 6 - 6 in FIG. 3 .
[0016] FIG. 7 is a perspective view of a mounting plate for the cooling jacket.
[0017] FIGS. 8A and 8B are front and back perspective views, respectively, of an exhaust elbow.
[0018] FIG. 9 is an end view of the exhaust elbow, as looking toward the cooling jacket.
[0019] FIG. 10 is a side view of the exhaust elbow.
[0020] FIGS. 11 and 12 are cross-sectional views, taken along lines 11 - 11 and 12 - 12 , respectively, in FIG. 9 .
[0021] FIG. 13 is a cross-sectional view, taken along line 13 - 13 in FIG. 10 .
[0022] FIG. 14 is a perspective view of a liquid-cooled exhaust manifold sized to house a catalytic conversion element.
[0023] FIGS. 15 and 16 are end and side views, respectively, of the manifold of FIG. 14 .
[0024] FIGS. 17 and 18 are cross-sectional views, taken along lines 17 - 17 and 18 - 18 , respectively, in FIG. 16 .
[0025] FIG. 19 is a cross-sectional view, taken along line 19 - 19 in FIG. 18 .
[0026] FIG. 20 is a top view of a liquid-cooled exhaust system including a manifold, turbocharger, and injection elbow.
[0027] FIG. 21 is an exploded perspective view of the exhaust system of FIG. 20 .
[0028] Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
[0029] Referring first to FIGS. 1A and 1B , cooling jacket 20 is sand or investment cast in a shape designed to form an interior cavity 22 sized to fit about an engine exhaust manifold (not shown) when the cooling jacket is mounted against the engine head. In this embodiment, the jacket includes a mounting boss 24 and associated exhaust port 26 through which exhaust gas flows from the manifold to a downstream exhaust elbow (shown in FIGS.
[0030] 8 A through 13 ). Accordingly, boss 24 features mounting holes 28 through which fasteners from the exhaust elbow extend into threaded bosses on the exhaust manifold, sandwiching the cooling jacket 20 between the manifold and elbow and sealing the exhaust passage. If desired, the cooling jacket may also be mounted securely to the engine cylinder head by appropriate lugs and fasteners (not shown).
[0031] Referring also to FIGS. 2-6 , cooling jacket 20 is cast to define an internal cooling passage or cavity 30 in hydraulic communication with a coolant inlet 32 , which is attached to a pressurized coolant source (not shown) for circulating coolant through the cooling jacket. From passage 30 , the coolant exits the cooling jacket through ports 34 in boss 24 and flows into the exhaust elbow, where it is blended with the exhaust gas. Alternatively, a separate coolant exit port (not shown) may be provided for returning the coolant to its source.
[0032] As shown in FIG. 3 , in this embodiment an air gap 31 is formed between the inner surface of the cooling jacket and the outer surface 33 of the exhaust manifold (shown in dashed outline). Alternatively, an appropriate insulating material, such as glass fiber (not shown), may be packed into this gap and provide insulation against heat conduction between the exhaust manifold and cooling jacket.
[0033] Cooling jacket 20 may be cast of any material suitable to the intended environment. For marine applications employing salt water as coolant, a salt resistant aluminum alloy is appropriate. If the cooling jacket is to be mounted directly against a cast iron engine head, or if very high temperatures are anticipated, cast iron may be more appropriate. If aluminum is used and exiting exhaust gas temperatures are high or the exhaust gas is particularly corrosive to aluminum, an iron sleeve may be provided through exhaust port 26 .
[0034] To completely enclose the exhaust manifold, a backing plate 36 may be employed as shown in FIG. 3 , and illustrated in FIG. 7 . The backing plate is made of flat metal stock, with appropriate exhaust ports placed to align with the exhaust ports of the engine cylinder head. Backing plate 36 is positioned as if it were an exhaust manifold gasket, between the cylinder head and manifold, with the manifold fasteners securing the backing plate in place. The outer edges of the backing plate engage the rim of the cooling jacket, such that there is no appreciable convective air flow through the cooling jacket.
[0035] Referring now to FIGS. 8A and 8B , exhaust elbow 38 is adapted to mount on boss 24 of cooling jacket 20 (see FIG. 1A ) via an appropriate mounting flange 40 . Exhaust inlet 42 aligns with exhaust port 26 of the cooling jacket ( FIG. 1A ), and appropriately positioned coolant inlets 44 align with the coolant outlet ports 34 of the cooling jacket ( FIG. 1A ), such that both the exhaust gasses and coolant enters exhaust elbow 38 separately. At its downstream end 46 , the exhaust elbow is coupled to the remainder of the exhaust system (not shown) in typical fashion.
[0036] Referring to FIGS. 9-13 , from mounting flange 40 and inlet 42 the exhaust gas flows straight through the exhaust elbow along a central exhaust passage 49 to an exhaust outlet 48 . The coolant flows through coolant passage 50 to the downstream end 46 of the exhaust elbow, where it exits the exhaust elbow at outlets 52 and joins the flow of exhaust gas. Coolant passage 50 is not completely annular at either end of the exhaust tube, due to the structural ribs required between the inner and outer portions of the exhaust elbow.
[0037] Referring next to FIGS. 14-16 , liquid-cooled manifold 54 is produced as a one-piece casting and is designed to merge the exhaust flows from three separate combustion cylinders (not shown) entering the manifold through three respective inlets 56 . The merged exhaust flows exit the manifold through exit 58 , after having passed through a catalytic conversion element contained within the manifold (discussed further below). Cooling liquid (e.g., fresh water or sea water) enters the manifold through port 60 and exits through port 62 .
[0038] As shown in FIGS. 17-19 , the manifold housing defines coolant passages 64 extending about the internal exhaust cavity 66 , for circulating liquid coolant through the manifold to control manifold housing surface temperature. Shown disposed within the housing just upstream of exhaust exit 58 in FIG. 17 is a catalytic conversion element 68 surrounded by an insulator 70 . Element 68 is a cylindrical, porous material designed to promote combustion of combustible exhaust gasses. Such materials are well known in the art of exhaust system design, and a suitable material is available from Allied Signal as their part number 38972. Element 68 has a reasonable porosity and size, at 600 cells per square inch, 3.0 inches in diameter and 2.6 inches in length, to perform its intended function without creating excessive exhaust back pressure. Insulator 70 is a rolled sheet of vermiculite, having a nominal uncrushed thickness of about 5 millimeters. Together, catalytic conversion element 68 and insulator 70 completely span exhaust exit 58 , such that all exhaust gas entering manifold 54 is forced to flow through element 68 before exiting the manifold. By disposing the conversion catalyst within the manifold itself, relatively close to the exhaust source, the high temperatures developed by secondary combustion are safely contained within a liquid-cooled housing so as to not present any exposed high temperature surfaces. As shown in FIG. 17 , a major length of catalytic element 68 is substantially surrounded by coolant passage 64 .
[0039] Although not specifically illustrated, it should be understood from the above disclosure that another advantageous arrangement is to house an appropriately sized catalytic conversion element, such as element 68 , within a manifold not adapted to circulate cooling fluid, and then surrounding the manifold with a secondary cooling jacket such as that shown in FIGS. 1-6 . It should also be understood that manifold 54 may be modified to provide the coolant exit coaxially with the exhaust exit, such that the exiting coolant flows directly into an injection elbow or other downstream exhaust component.
[0040] Referring now to FIGS. 20 and 21 , liquid-cooled exhaust system 72 includes a liquid-cooled exhaust manifold 74 , a liquid-cooled turbocharger 76 , and a coolant injection elbow 78 . The individual exhaust system components are shown separated in FIG. 21 . Manifold 74 is configured to receive the exhaust from a bank of six combustion cylinders through exhaust inlets 80 , and a flow of coolant through coolant inlet 82 . From manifold 74 , both the combined exhaust stream and the liquid coolant pass directly into the housing of turbocharger 76 through ports 84 and 86 , respectively. The passed coolant helps to control the surface temperature of turbocharger 76 , which uses kinetic flow energy from the exhaust gas to boost the pressure of intake air for combustion in the associated engine. Turbocharger 76 accepts atmospheric air through intake 88 and supplies pressurized air to the engine via air outlet 90 . From turbocharger 76 , both the exhaust stream and the liquid coolant flow directly into injection elbow 78 , through ports 92 and 94 , respectively. In elbow 78 the coolant is injected into the stream of exhaust to further cool the exhaust. The placement of turbocharger 76 immediately downstream of manifold 74 , before the exhaust stream has experienced substantial flow losses, promotes turbocharging efficiency. In addition, flowing the coolant through the turbocharger helps to maintain desirable external turbocharger housing surface temperatures in systems employing downstream water injection, such as for marine applications. It should be understood from the above disclosure that any of the three components shown in FIG. 21 may be equipped with an internal catalytic conversion element, such as element 68 of FIG. 17 , and that manifold 74 may be replaced with a standard manifold without internal coolant channels but rather surrounded by a cooled jacket such as the one shown in FIGS. 1-6 .
[0041] A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, a single manifold/jacket assembly may replace the standard exhaust manifold and contain both internal exhaust passages and internal coolant passages, with an internal air space between the coolant passages and exhaust passages such that many of the benefits of the invention are achieved. Because of direct exposure to high temperature exhaust gasses, however, such a combination version would be limited to particular materials, such as cast iron or steel. Accordingly, other embodiments are within the scope of the following claims.
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An exhaust manifold cooling jacket has internal passages for the circulation of liquid coolant and encloses an exhaust manifold such that a gap is created between the exhaust manifold and cooling jacket. Flowing coolant through the jacket regulates outer jacket temperature while enabling high intra-manifold exhaust gas temperatures for thorough intra-manifold combustion and improved emissions. A liquid-cooled exhaust system includes a turbocharger disposed between manifold and elbow, with liquid coolant flowing from manifold to elbow through the turbocharger. Another liquid-cooled exhaust manifold contains an internal exhaust combustion catalyst wrapped in an insulating blanket. In some marine applications, seawater or fresh water coolant is discharged into the exhaust gas stream at an attached exhaust elbow.
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This is a continuation of copending application Ser. No. 07/414,868 filed on Sep. 29, 1989, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to optical storage, and more particularly to a detection system for magneto-optical storage.
DESCRIPTION OF THE PRIOR ART
Optical recording systems have come into use in recent years because of their potential for high density recording. One approach for optical recording is magneto-optical recording in which a focussed laser beam is pulsed to high power for a short time to raise the temperature of a perpendicularly magnetized recording medium sufficiently for an externally applied magnetic field to reverse the direction of magnetization in the heated region. When the medium returns to a lower temperature for readout, the reverse-magnetized domain persists. Readout of information employs the polar Kerr effect. Linearly polarized light, reflected from a perpendicularly magnetized medium, is rotated to the left or right, according to the direction of the plane of polarization of the reflected light, magnetization direction along a recorded track can be read out by the same focussed laser beam that was used for recording information.
A detector system is provided to sense the magnetic transitions, and to provide focussing and tracking signals to maintain the laser spot in precise position relative to the disk surface and data tracks. In magneto-optical storage systems with Pulse Width Modulation (PWM), the location of one bits are encoded by the positions of transitions between up and down magnetic domains. In prior art systems, these transitions have been sensed electronically as a change in the difference between the currents produced by two light detectors.
For example, Japanese PUPA 59-79446 shows apparatus including two detectors each of which is sensitive to light oriented in one direction. This detection apparatus essentially discards one-half of the signal light.
U.S. Pat. No. 3,992,575 has apparatus for changing the optical path length so that three different lengths can be obtained for determining whether the read beam is properly focussed, and U.S. Pat. No. 4,065,786 discloses a push-pull tracking system which senses the detected signal and a tracking error signal which permits the beam to be maintained on track.
U.S. Pat. No. 4,059,841 discloses a non-magneto-optical system which utilizes four detectors and differential reading of the signal along the track. The detection signal is obtained by means of electronic circuits which add electrical noise. The signal-to-noise ratio imposes a limit on the minimum bit size that can be recorded so the added electrical noise directly impacts the recording density that can be achieved.
No prior art is known in which the edge of the magneto-optical domains are detected optically.
SUMMARY OF THE INVENTION
It is therefore the principal object of this invention to provide a magneto-optical storage detection system in which the edges of the magneto-optical domains are detected optically.
In accordance with the present invention, a magneto-optical storage detection system comprises a source of radiation, means for directing the source of radiation to a storage medium upon which marks are recorded, and means for directing the radiation reflected from the recorded mark to a detection channel. The detection channel comprises means for detecting the recorded data which is sensitive to the transitions between the domains of a first and a second magnetization state so that an electrical signal is produced in response to the detected transitions which is indicative of the recorded data.
In a specific embodiment, the means for detecting the recorded data comprises an optical matched filter in conjunction with a dual optical detector.
For a fuller understanding of the nature and advantages of the present invention reference should be made to the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically shows a magneto-optical storage detection system according to the present invention.
FIG. 2 shows the signal waveform which results from detection of a recorded transition according to the present invention.
FIG. 3 shows an alternate embodiment of the magneto-optical storage detection system according to the present invention.
FIG. 3a shows a specific embodiment of the split photodetector 26.
FIG. 4 schematically shows an alternate embodiment of a magneto-optical storage detection system.
FIG. 5 shows the signal waveform which results from detection of a recorded transition in the system of FIG. 4.
FIG. 6 shows an alternate embodiment of the magneto-optical storage detection system of FIG. 4.
FIG. 7 shows an alternate embodiment of the matched filter of FIG. 4.
FIG. 8 is a further embodiment of a magneto-optical storage detection system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIG. 1 of the drawings, the detector system for magneto-optical storage comprises a radiation source 10 which in a specific embodiment comprises a laser. The laser produces a collimated beam 12 which is directed through a 70% transmitting beam splitter 14 and a polarization analyzer 16. Polarization analyzer 16 reflects x polarized light and transmits y polarized light. The y polarized beam transmitted through the analyzer 16 is then incident on a birefringent compensator plate 18 which produces a small x polarized component out of phase with the y component. This x component acts as the phase shifted local oscillator necessary for far field edge detection according to the present invention.
In the embodiment shown in FIG. 1, the compensator plate 18 comprises a quarter wave plate oriented at an optimum angle with respect to both the x and y directions so that linearly polarized input light is made elliptically polarized. The beam is then directed by turning mirror 20 to objective lens 22 which focuses the beam to a selected location on magneto-optical recording disk 24. Items 20 through 24 are rotated 90 degrees for clarity in the drawing. The reflected light from a previously recorded signal is then guided to the detection system by the same optical components including the objective lens 22, turning mirror 20 and birefringent compensator plate 18. As the reflected beam passes through birefringent compensator plate 18, the beam is made more elliptically polarized. After propagating through the birefringent plate 18, the x polarized component is directed into the data detection beam line by the polarization analyzer 16. Part of the y polarized component is directed into the servo system (not shown) by beam splitter 14, and the rest returns to the laser. The x component is directed into the split photodetector 26. When no recorded transition is present on the selected location on recording disk 24, equal illumination is produced on both photodiodes 28 and 30 which make up split photodetector 26. When resulting signals are sensed differentially, no net signal results. However, when a recorded transition is present, the optical power is greater on one photodiode 28 than the other 30 and a detection signal is produced by sensing means 31.
FIG. 2 shows a typical signal produced by a reversal of magnetization along the track which shows marks recorded as domains of up and down magnetization to produce recorded domain 32 and in which two positions of the laser beam are shown as dashed circles. The light reflected by the recording medium can be decomposed into a local oscillator component along the direction of the incident laser, and a signal component in the orthogonal direction. The sign of this signal component changes at a transition. When a transition is located at the center of the laser spot, the power at the left detector 28 is different from the detector 30 on the right. In regions of uniform magnetization, both the left detector 28 and the right detector 30 have identical illumination. Thus, as the laser spot scans over the recorded transition 33, the difference in power leads to a difference in the photocurrents i L -i R of the two sides of the detector which is produced by circuits within sensing means 31 and this difference varies as shown in FIG. 2. The operation of the detection system does not depend critically upon the method of producing the x component which acts as the phase shifted local oscillator necessary for far field edge detection.
An alternate embodiment of the invention is shown in FIG. 3 in which the x component, which is directed into the data detection beam line, is partially focused by a lens 34 and directed into the split photodetector 26. When the split photodetector 26 is placed at or near the focal plane of lens 34, the phase shift required for the local oscillator is zero or quite small. Such a local oscillator can be obtained by replacing the birefringent plate 18 in FIG. 1 with a diattenuating element. A diattenuating element is an optical device with a transmission or attenuation coefficient that depends upon polarization, sometimes termed a partial polarizing element, weak polarizer or dichroic element. One suitable such device is a Brewster plate 36 (FIG. 3) oriented at about 45 degrees with respect to the y axis so that the plane of linearly polarized light is rotated. The light that is reflected from the recording medium then propagates back through the Brewster plate 36, and the x polarized component is picked off by polarization beam splitter 16 and directed into the detection channel. The remaining y polarized light goes back to the servo channel and the laser. The lens 34 then reimages the plane of the medium onto (or very near) the split photodetector 26. Such a re-imaging edge detection channel is distinct from but operates in a manner similar to the far field system in FIG. 1. The line of the split in the photodetector may be straight or curved to best match the shape of the images of the edges of the magnetic domains. An example of photodetectors for a curved line is shown in FIG. 3a.
An alternate embodiment of a detector system for magneto-optical storage is shown in FIG. 4, and this system comprises a radiation source 10 which produces a collimated beam 12 which is directed through a polarization beam splitter 40 which reflects 100 per cent of the x polarized light along with about 25 percent of the y polarized light. The transmitted light is directed to a selected area of the magneto-optical recording disk 24 by means of turning mirror 20 and objective lens 22. Ideally, there is no phase shift between x and y polarization on reflection from the disk 24, and the reflected light is directed into the data detection beam line by beam splitter 40. The resulting beam is directed to polarization insensitive beam splitter 42 which separates the servo channel from the signal channel. In the signal channel, the light passes through a variable compensator plate 44 which imposes a phase shift between x and y polarizations. A matched filter 46, a half wave plate 48 and a polarization beam splitter 50 then direct beams of equal intensity and orthogonal polarization into two separate photodiodes 52 and 54. Lens 49 merely insures that all light reaches the photodetectors 52 and 54.
The matched filter 46 is designed to direct essentially all the x polarized signal light into one photodetector or another, and differs from previously disclosed optical matched filters by incorporating birefringent optical elements. Another embodiment of the matched filter is shown in FIG. 8. In this embodiment a half of a half wave plate 60 is placed in the path between the variable compensator plate 44 and the half wave plate 48. This embodiment provides a far-field separated detector edge detection system. In this embodiment of the filter the collimated beam returning from the medium and having passed through the compensator plate 44 is affected by the birefringent filter as follows: The optical length of the filter for light polarized in the local oscillator (y) direction is constant across the filter aperture, whereas in the orthogonal (x or signal) polarization the optical length changes by one half wave along a diameter of the filter. When the signal polarization has a uniform sign at the filter plane, this matched filter reverses the sign for half of the beam area. The signal amplitude averaged over the beam area is zero, and the optical powers on the two detectors 52 and 54 are equal. The adjustable half wave plate 48 is oriented to equalize the local oscillator powers at the two detectors. When a transition is centered under the read laser beam, the sign reversal of the signal polarization amplitude due to the difference in Kerr rotations for up and down magnetization is compensated by the reversal due to the filter phase shift. The average polarization of the light exiting the filter is altered, causing an imbalance in the powers reaching the two detectors 52, 54. The resulting electrical signals are similar to those in FIG. 2. Proper operation of this far-field matched filter system requires that the compensator plate 44 be adjusted to impose a 90 degree phase shift between y and x polarized light when the Kerr ellipticity of the medium is zero and the incident read beam is linearly polarized as shown. Other cases require different compensator phase shifts.
An alternate embodiment of the matched filter is shown in FIG. 6, and in this embodiment a first lens 55 is provided to focus the reflected beam onto a spatially non-uniform birefringent element. A second lens 57 recollimates this beam and directs it through half wave plate 48. In a specific embodiment the spatially non-uniform birefringent element comprises a half wave plate 56 positioned with an edge 58 which matches the edge of the domain as shown in FIG. 7 of the drawing.
The optical length of the filter for light polarized in the local oscillator direction (y) is constant, whereas in the orthogonal polarization, the optical length changes by one half wave along a straight or curved line which best matches the curved edge of the image of the recorded mark on the recording medium 24. When the signal polarization has a uniform sign across the image, the matched filter reverses the sign for half of the image area. The signal amplitude averaged over the image is zero, and the polarization exiting the filter is the same as the local oscillator polarization. The optical powers on the two detectors 52, 54 are then equal. When a transition is imaged onto the filter 56, the reversal of the signal amplitude due to Kerr-rotation is compensated by the reversal due to the filter phase shift. The polarization of the light exiting the filter is rotated, causing an imbalance in the power at the two detectors 52, 54. The resulting electrical signal is as shown in FIG. 5 which shows a magnetic domain 53 written by direct overwrite. Leading edge signals have opposite sign to trailing edge signals. The widths are narrower than the width of conventionally measured signals because the filter compensates for the curvature of the edges of the domain. No light is lost to apertures since the matched filter 46 alters phase only.
A further embodiment comprises the use of a birefringent hologram or grating system to replace the imaging optics and the matched filter. The hologram would have approximately the same optical transfer function as the filter previously described. Such a hologram can be obtained by superimposing the hologram of a domain boundary in one polarization with that of a uniform track in the other polarization, both as imaged though the objective lens.
While the preferred embodiments of the present invention have been illustrated in detail, it should be apparent that modifications and adaptations to those embodiments may occur to one skilled in the art without departing from the scope of the present invention as set forth in the following claims.
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A magneto-optical (M-O) storage detection channel which includes optical means for detecting edge transitions between magneto-optical domains. The beam returning from the storage medium is analyzed both spatially and in polarization. When a transition is centered under the read laser beam, the spatial reversal in the sign of the amplitude of the signal polarization due to the spatially nonuniform Kerr rotation is compensated by a reversal due to spatially nonuniform (split) detectors or a matched optical filter. The optical powers on the two sides of each split detectors or on two independent detectors sensitive to orthogonal polarizations become unequal thereby producing an electrical signal signal which comprises spaced peaks in opposite directions at the leading and trailing edges of the M-O domain or mark.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an electric connector configured such that first and second connectors are fitted to each other in a direction approximately perpendicular to a multipolar arrangement direction of conductive terminals (contacts).
[0003] 2. Description of the Related Art
[0004] Generally, in various electric apparatuses, it has been widely performed to connect a plurality of coaxial cables, a flexible circuit board, or the like to a printed circuit board via a pair of electric connectors configured to allow fitting connection to each other. As the pair of electric connectors, for example, a receptacle connector (first connector) mounted on a printed circuit board and a plug connector (second connector) fitted to the receptacle connector are used. In a state in which end portions of a plurality of coaxial cables, an end portion of a flexible circuit board, or the like are joined to the plug connector, the plug connector is fitted in the receptacle connector.
[0005] Regarding the pair of electric connectors thus configured to allow mutual fitting, for example, as disclosed in JP-A-2002-280102, there has been conventionally known a vertically-fitting type electric connector in which the above-described plug connector is plugged and fitted in a direction approximately perpendicular to a multipolar arrangement direction of conductive terminals (contacts), namely, in a direction approximately perpendicular to a plane of the printed circuit board mounted with the receptacle connector.
[0006] However, also in such a vertically-fitting type electric connector, lowering in height and downsizing have been rapidly promoted as in the case of another electric connector, since space allowing displacement of conductive terminals at a fitting time is reduced so that contact pressure of the conductive terminals is lowered, which may result in a problem in contact reliability which is the most fundamental performance required for an electric connector.
[0007] Further, in a recent electric connector, for the purpose of preventing malfunction of an apparatus due to noise according to increase in speed of an electric signal, reducing influence of electromagnetic waves on the human body, and the like, improvement of properties of electromagnetic interference (EMI) and electrostatic discharge (ESD) is an urgent need. However, in a general electric connector, for example, as disclosed in JP-A-2005-302417, since a conductive shell covering an insulating housing has no arrangement relationship with conductive terminals, sufficient properties of electromagnetic interference (EMI) and electrostatic discharge (ESD) cannot be obtained in the present circumstances.
[0008] Therefore, an object of the present invention is to provide an electric connector which can maintain contact reliability of conductive terminals well and simultaneously can achieve improvement of properties of electromagnetic interference (EMI) and electrostatic discharge (ESD) even if being lowered in height and downsized.
SUMMARY OF THE INVENTION
[0009] In order to achieve the above object, an electric connector according to the present invention includes a first connector and a second connector each of which is provided with a plurality of conductive terminals arranged at suitable pitch distances in a multipolar manner along a longitudinal widthwise direction of a slender flat plate-like insulating housing and a conductive shell covering an outer surface of the insulating housing, where the first and second connectors are fitted to each other in a direction approximately perpendicular to a direction of the multipolar arrangement so that the conductive terminals of the first and second connectors and the conductive shells thereof are brought in contact with each other, respectively, to form a terminal connecting portion CS and a shell connecting portion SS, wherein the shell connecting portion SS is disposed opposite to the terminal connecting portion CS through the insulating housing of the second connector in a direction perpendicular to a fitting direction of the first and second connectors.
[0010] According to the electric connector having such a configuration, since the shell connecting portion SS disposed opposite to the terminal connecting portion CS of the first and second connector functions to maintain contact pressure at the terminal connecting portion CS well, electric contact performance of the terminal connecting portion CS is improved.
[0011] Further, since the shell connecting portion is disposed opposite to the terminal connecting portion CS, a shield wire formed by the conductive shells of both the connectors is formed continuously, and it further becomes possible to dispose the shield wire along an electric signal wire formed by the conductive terminals of both the connectors, so that electromagnetic waves generated by the electric signal wire can be shielded well.
[0012] As described above, according to the electric connector according to the present invention, even if an electric connector is lowered in height and downsized, contact reliability of conductive terminals can be maintained well, and simultaneously improvement of properties of electromagnetic interference (EMI) and electrostatic discharge (ESD) can be achieved, so that reliability of the electric connector can be improved at low cost.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is an appearance perspective explanatory view showing a state of an electric connector for coaxial cables according to an embodiment of the present invention just before fitting thereof;
[0014] FIG. 2 is a cross sectional explanatory view showing a structure of a plug connector used in FIG. 1 ;
[0015] FIG. 3 is a cross sectional explanatory view showing a structure of a receptacle connector used in FIG. 1 ;
[0016] FIG. 4 is a cross sectional explanatory view of a state in which the connectors shown in FIG. 1 have been fitted to each other;
[0017] FIG. 5 is a plan explanatory view showing a state of the plug connector used in FIG. 1 just after being soldered and connected with coaxial cables and just before mounted with an upper conductive shell;
[0018] FIG. 6 is an appearance perspective explanatory view showing a bottom face structure of the plug connector used in FIG. 1 ;
[0019] FIG. 7 is an appearance perspective explanatory view showing a top face structure of the receptacle connector used in FIG. 1 ;
[0020] FIG. 8 is an appearance perspective explanatory view showing a VIII portion of the receptacle connector shown in FIG. 7 in an enlarged manner;
[0021] FIG. 9 is a cross sectional explanatory view showing a IX portion of the receptacle connector shown in FIG. 3 in an enlarged manner; and
[0022] FIG. 10 is a cross sectional explanatory view showing an X portion shown in FIG. 4 in a state in which both the connectors are fitted to each other in an enlarge manner.
DETAILED DESCRIPTION OF EMBODIMENTS
[0023] Hereinafter, an embodiment of the present invention applied to an electric connector which connects a plurality of coaxial cables to a printed circuit board will be explained in detail with reference to the drawings.
[0024] First, an electric connector shown in FIG. 1 includes a receptacle connector (first connector) 2 mounted on a printed circuit board 1 and a plug connector (second connector) 3 fitted to the receptacle connector 2 . That is, an electric connector according to the present invention has a vertically-fitting type configuration in which the plug connector 3 which is disposed just above the receptacle connector 2 is brought down in FIG. 1 in a direction approximately perpendicular to the printed circuit board 1 to plug a fitting portion of the plug connector 3 into a fitting portion of the receptacle connector 2 so that both the connectors are fitted to each other.
[0025] Hereinafter, a direction in which the plug connector 3 is plugged is downward, and an opposite direction in which the plug connector 3 is unplugged is upward.
[0026] As shown in FIGS. 2 to 7 , the receptacle connector (first connector) 2 and the plug connector (second connector) 3 include insulting housings 21 and 31 extending to be formed of a slender plate, respectively. A plurality of conductive terminals (contacts) 22 and 32 are arranged at suitable pitch intervals in a multipolar manner along longitudinal directions of the slender insulating housings 21 and 31 . Further, an approximately entire outer surface of the insulating housing 31 of the plug connector 3 is covered with a metal conductive shell 33 , and an outer peripheral portion of the receptacle connector 2 is covered with a metal conductive shell 23 . One of edge portions of the plug connector 3 in a longitudinal direction thereof is joined with terminal portions of a plurality of coaxial cables 4 arranged in parallel in a multipolar manner.
[0027] Hereinafter, the end edge portion on the rear side joined with the end portions of the coaxial cables 4 is called “rear end edge portion”, and the other end edge portion on the front side opposite to the rear end edge portion is called “front end edge portion”, and besides end edge portions of the receptacle connector 2 corresponding to the rear end edge portion and the front end edge portion of the plug connector 3 are similarly called “rear end edge portion” and “front end edge portion”, respectively.
[0028] Covering material of the end portions of the coaxial cables 4 are removed to expose cable central conductors (signal wires) 4 a and cable outer conductors (shield wires) 4 b . The cable central conductors 4 a each of which is disposed along the center of axis are collectively soldered and connected by using, for example, a bar-like solder to the conductive terminals (contacts) 32 of the plug connector 3 described above, respectively. Further, the cable outer conductors 4 b each of which is disposed to surround an outer periphery of the cable central conductor 4 a are soldered and connected in a state of being sandwiched and supported from above and below by ground bars 34 and 34 disposed vertically in pair to be retained. Incidentally, the coaxial cables 4 and the conductive terminals (contacts) 32 of the plug connector 3 can be connected to each other by crimping connection, insulation displacement connection, or the like.
[0029] The above-described conductive shell 33 of the plug connector (second connector) 3 includes an upper conductive shell 33 a and a lower conductive shell 33 b that form the upper face and the lower face in FIG. 1 , respectively. Further, the lower conductive shell 33 b of these shells is subjected to insert molding to be exposed on a bottom face (lower face in FIG. 1 ) of the above-described insulating housing 31 .
[0030] Further, the upper conductive shell 33 a is slid from the front end edge portion to be fitted to the upper face side of the insulating housing 31 in a state after the above-described soldering connection of the coaxial cables 4 (in particular see FIG. 5 ), and fixed to cover the upper face side of the insulating housing 31 almost entirely. At that time, the front end edge portion of the upper conductive shell 33 a forms a bent outer end piece 33 c bent downward at an approximately right angle, so that the front end face of the insulating housing 31 is covered with the bent outer end piece 33 c from outside.
[0031] Further, a plurality (three) of plate-spring-like elastic connecting tongue pieces 33 d on the upper side is formed on the rear end edge portion of the upper conductive shell 33 a at suitable intervals along its longitudinal direction. Each of the elastic connecting tongue pieces 33 d is formed in a notched manner like a cantilever, and distal end portions (rear end portions) of the elastic connecting tongue pieces 33 d are brought in pressure contact with the upper surface of the above-described upper ground bar 34 from above.
[0032] In this manner, in the plug connector 3 serving as the second connector, the upper face (plane), lower face (bottom face), front face and both side faces of the insulating housing 31 , namely, an approximately entire face of the insulating housing 31 is covered with the conductive shell 33 . This is a preferable structure in obtaining electromagnetic shielding effect, but it is not necessarily needed to have a structure in which the conductive shell 33 covers the entire of the insulating housing 31 .
[0033] On the other hand, the above-described conductive shell 23 provided on the receptacle connector 2 serving as the first connector is disposed to surround a portion of the insulating housing 21 extending from the front end edge portion thereof to both end edge portions in a longitudinal direction thereof. Holddowns 23 a and 23 b bent to project forward and backward are formed on both end portions of the conductive shell 23 in a longitudinal direction thereof, respectively. A holddown 23 c to project forward is also formed on an approximately central portion of the front end edge portion of the conductive shell 23 in the longitudinal direction. The holddowns 23 a , 23 b , and 23 c are soldered and joined to a ground electrically-conducting path (not shown) on the printed circuit board 1 to perform electrical connection and fixation of the entire receptacle connector 2 .
[0034] Further, front end edge side portions of the conductive terminals (contacts) 22 provided on the receptacle connector (first connector) 2 are formed to project forward from the front end edge portion of the insulating housing 21 , and the forwardly projecting portions are each soldered and joined to a signal electrically-conductive path (not shown) on the printed circuit board 1 to perform electrical connection.
[0035] Further, the above-described front end edge portion 23 d of the conductive shell 23 of the receptacle connector (first connector) 2 is formed into an approximately L shape in cross section to cover, from above, a convex portion 21 a formed to extend like a standing wall in a longitudinal direction at the front end edge portion of the insulating housing 21 . That is, as shown in FIG. 8 and FIG. 9 in particular, the front end edge portion 23 d of the conductive shell 23 is erected to cover the front end face of the above-described convex portion 21 a of the insulating housing 21 , bent at an approximately right angle from an upper end position of the front end edge portion 23 d in the erecting direction to extend rearward along the upper face of the insulating housing 21 , and then bent downward at an approximately right angle to form an inner end edge portion 23 e extending downward.
[0036] The inner end edge portion 23 e extending downward is formed in a longitudinal member extending along a longitudinal direction of the receptacle connector 2 , and a plurality of elastic connecting tongue pieces 23 f is disposed in an intermediate position in a longitudinal direction of the inner end edge portion 23 e at suitable intervals along the longitudinal direction. Each of the elastic connecting tongue pieces 23 f is formed in a notching manner like a cantilever so that it has suitable elasticity. A lower end portion of each of the elastic connecting tongue pieces 23 f is provided to extend obliquely rearward, and the portion extending obliquely rearward comes in pressure contact with the above-described bent outer end piece 33 c provided on the front end side of the plug connector 3 .
[0037] That is, as described above, the plug connector 3 serving as the second connector is plugged downward (in a direction approximately perpendicular to a multipolar arrangement direction of the coaxial cable 4 ) and fitted to the receptacle connector 2 serving as the first connector, and when both the connectors 2 and 3 are fitted to each other, as shown in FIG. 10 in particular, the conductive terminals (contacts) 22 and 32 provided on both the connectors 2 and 3 respectively are brought in contact with each other to form terminal connecting portions CS at the contact portions, and simultaneously, the bent outer end piece 33 c provided on the upper conductive shell 23 of the plug connector 3 comes in pressure contact with each of the elastic connecting tongue piece 23 f of the conductive shell 23 provided on the receptacle connector 2 to form shell connecting portions SS at the contact potions.
[0038] At this time, in the above-described terminal connecting portion CS, a bent projecting portion 22 a of the conductive terminal 22 of the receptacle connector 2 is brought in pressure contact with a concave groove portion 32 a provided on the conductive terminal 32 of the plug connector 3 in an undulated manner. As a result, an electric signal supplied via the above-described cable central conductor (signal wire) 4 a of the coaxial cable 4 is sent to the front end of the plug connector 3 via each conductive terminal (contact) 32 of the plug connector 3 , and then transmitted to each conductive terminal (contact) 22 of the receptacle connector 2 via the terminal connecting portion CS, so that the electric signal flows in an approximately S shape corresponding to a bent shape of the conductive terminal 22 to be supplied to the printed circuit board 1 .
[0039] The cable outer conductor (shield wire) 4 b of the coaxial cable 4 is electrically connected by bring the upper and lower ground bars 34 and 34 in pressure contact with the elastic connecting tongue piece 33 d positioned on the upper side of the upper conductive shell 33 a and the lower conductive shell 33 b of the plug connector 3 . The bent outer end piece 33 c provided on the front end side of the upper conductive shell 33 a is connected to the conductive shell 23 of the receptacle connector 2 via the above-described shell connecting portion SS, so that a shield wire along a signal wire for the electric signal is formed.
[0040] That is, the above-described terminal connecting portion CS and shell connecting portion SS are disposed at about the same level in height in a height direction from the printed circuit board 1 , and the shell connecting portion SS is disposed opposite to the terminal connecting portion CS in an anteroposterior direction (in a direction perpendicular to a fitting direction of both the connectors 2 and 3 ). The insulating housing 31 of the plug connector 3 is interposed between the shell connecting portion SS and the terminal connecting portion CS. By pressing forces opposite to each other in an anteroposterior direction generated between the shell connecting portion SS and the terminal connecting portion CS through the insulating housing 31 interposed therebetween by the elastic connecting tongue piece 23 f positioned on the front end side of the conductive shell 23 and the bent projecting portion 22 a of the conductive terminal 22 (see arrow in FIG. 9 ), a contact state in particular in the terminal connecting portion CS is retained well.
[0041] Further, as described above, since the shell connecting portion SS is disposed opposite to the terminal connecting portion CS in an anteroposterior direction, the shield wire formed by both the conductive shells 23 and 33 of both the connectors 2 and 3 is continuously formed. At this time, the shell connecting portions SS forming the shield wire is disposed at a position near the terminal connecting portion CS disposed in the deep portion inside the connector. Therefore, the shield wire is formed along the above-described electric signal wire formed in an approximately-S shape by the conductive terminals 22 and 23 of both the connectors 2 and 3 . As a result, shielding of electromagnetic waves generated by the electric signal wire is performed well.
[0042] As described above, according to the embodiment, since the shell connecting portion SS is disposed opposite to the terminal connecting portion CS formed when the receptacle connector 2 as the first connector and the plug connector 3 as the second connector fit each other, the pressing force at the shell connecting portion SS functions to maintain contact pressure at the terminal connecting portion CS well, as a result, electric contact performance of the terminal connecting portion CS is improved.
[0043] Further, since the shell connecting portion SS is disposed at a position related to the vicinity of the position of the terminal connecting portion CS, the conductive shells 23 and 33 are disposed approximately along the electric signal wire passing through the conductive terminals 22 and 32 , thereby a shielding function of the conductive shells 23 and 33 to electromagnetic waves generated from the electric signal wire is performed well.
[0044] Though the present invention made by the present inventor(s) has been explained above based upon the embodiment, it is obvious that the present invention is not limited to the above-described embodiment and can be variously modified without departing from the scope of the present invention.
[0045] For example, in the above-described embodiment, a portion constituting the shell connecting portion SS in the conductive shell 23 of the receptacle connector (first connector) 2 is elastically displaceable or deformable, but it is possible to adopt a configuration that a portion constituting the shell connecting portion SS of the plug connector (second connector) 3 or both the portions are elastically displaceable or deformable.
[0046] Further, the present invention is not limited to a connector for coaxial cables such as the above-described embodiment and can be similarly applied to an electric connector of a type that a plurality of coaxial cables and a plurality of insulating cables are mixed, an electric connector to which a flexible circuit board or the like is joined, and the like.
[0047] Further, the present invention can be variously modified to have a structure in which the conductive shell of the plug connector does not include the upper conductive shell and the lower conductive shell as described above, but is integrally formed instead, a structure that the conductive shell is divided into three or more, and the like.
[0048] As described above, the present invention can be widely applied to various electric connectors used in various electric apparatuses.
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Such a configuration is achieved that shell connecting portion which is a contact portion of conductive shells of first and second connectors fitted to each other in a direction approximately perpendicular to multipolar arrangement is disposed opposite to a terminal connecting portion which is a contact portion of conductive terminals, so that contact pressure at the shell connecting portion is caused to function on the terminal connecting portion to improve electric contact performance of the terminal connecting portion, and the conductive shells are disposed approximately along the conductive terminals to improve a function for shielding electromagnetic waves generated based upon electric signals flowing in the conductive terminals. By adopting such a configuration, even if an electric connector is lowered in height and downsized, contact reliability of the conductive terminals is maintained well, so that improvement of properties of electromagnetic interference (EMI) and electrostatic discharge (ESD) can be achieved.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 62/043,665 filed Aug. 29, 2014, which is incorporated herein in its entirety by reference.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention generally relate to systems for blending a plurality of fuels. Specifically, embodiments of the present invention relate to systems that blend a plurality of fuels and optimize the blend, based on a variety of parameters such as price, fuel pressure, etc.
BACKGROUND OF THE INVENTION
[0003] Alternative fuels such as natural gas, propane, ethanol, hydrogen, biodiesel, butanol, methanol, and P-Series fuels are becoming increasingly popular and are supplementing traditional fuels such as gasoline and diesel. Users select these alternative fuels for a variety of reasons. For example, a user may desire the most cost effective fuel, and different governments may offer incentives for a user to buy certain types of fuel. Further, a user may be constrained by geography since alternative fuels have varying availability in different locations. Therefore, a user may choose a certain type of fuel because of its availability in a particular area.
[0004] While some alternative fuels may be preferable in some instances, they may not be preferable in every situation. For example, a natural gas supply may experience pressure drops, pressure spikes, other service interruptions, and even quality issues such as inconsistent energy content (BTU). Further scenarios include prices of various fuels changing over time, government incentives expiring or beginning, and a change in location of an engine. Therefore, it is desirable for an engine to have the capability of using more than one fuel so that a user may optimize fuel consumption for minimal price, location, or any other parameters.
[0005] There have been some previous efforts that attempt to address the issue of fuel optimization. For example, U.S. Pat. No. 8,061,121, which is incorporated herein by reference in its entirety, envisions a system where a car tank may be filled with traditional gasoline or an ethanol blend. A sensor detects the amount of alcohol in the air-fuel mixture, and based on sensor's measurement the system adjusts whether to operate the engine conventionally at stoichiometry or in a lean combustion mode. In a further system, U.S. Patent Publication No. 2011/0114058, which is incorporated herein by reference in its entirety, contemplates a system with two tanks one tank filled with gasoline and one tank filled with natural gas. This system comprises specialized bi-fuel spark ignition engine that allows the engine to operate on gasoline, natural gas, or a combination of the two.
[0006] One limitation with the prior art is that it does not contemplate a user's desire to use as much primary fuel as possible even in the face of quality issues, quantity problems, or other similar concerns. While alternative fuels may hold certain advantages in certain instances, it may be desirable (e.g., cost effective) to use as much primary fuel as possible while dealing with quantity issues, etc. Further none of the primary art devices allow for an uninterrupted supply of fuel when one source of fuel is abruptly shut off. This limitation with prior art devices results in performance issues with the engine, for example, a reduction in engine speed or RPMs. Due to these limitations associated with the prior art and more, the following disclosure describes an improved multi-source gaseous fuel blending manifold.
SUMMARY OF THE INVENTION
[0007] The above needs and other needs are addressed by the various embodiments and configurations of the present invention. This invention relates to a novel system, method, or device that blends multiple sources of fuel.
[0008] It is one aspect of various embodiments of the present invention to provide a system for blending multiple sources of gaseous fuel to maintain the continuity of operation and the performance of an engine. For example, one embodiment of the present invention includes a second fuel train that supplements a first fuel train in the event that the first fuel trains suffers from an interruption in fuel supply, fuel quality, etc., thus ensuring continuous operation and consistent performance of the engine.
[0009] It is another aspect of some embodiments of the present invention to provide a system for blending multiple sources of gaseous fuel to optimize a parameter of a gaseous fuel. Optimization may be applied to any discernible parameter of a gaseous fuel such as carbon content, price, octane number, sulfur content, Reid vapor pressure, minimum operating pressure of said engine, fuel price, energy content, peak flame temperature, flammability lower limit on a percent volume-basis, flammability upper limit on a percent volume-basis, stoichiometric air to fuel ratio on a mass basis, cetane number, etc. Further, parameters of the gaseous fuels may be prioritized for optimization. For example, in one embodiment of the present invention the gaseous fuel blend must meet a certain emissions profile. After this condition has been met, the gaseous fuel blend may be optimized by price. In an additional example, it may be desirable to use as much primary fuel as possible while only supplementing the primary fuel to maintain the fuel blend above a pressure threshold, BTU threshold, etc. It will be appreciated that other various discernible parameters of gaseous fuels and optimization logic are described in greater detail below.
[0010] It is one aspect of various embodiments of the present invention to provide a system for blending multiple sources of gaseous fuel that comprises a plurality of fuel trains. As mentioned above, a first fuel train may be supplemented by a second fuel train to account for any issues with the first fuel train such as supply interruption. Further embodiments of the present invention may also include a third fuel train, a fourth fuel train, and so on. Embodiments of the present invention that include a plurality of fuel trains have more options to optimize a blend of gaseous fuels. For example, a second fuel train may supplement a first fuel train to ensure stable pressure and cheaper price, but the first and second fuel blend may not have the requisite BTUs. Thus, a third fuel train blends with the second fuel train before blending with the first fuel train to meet all pertinent requirements. Additionally, a given fuel train may comprise a plurality of fuel sources. It will be appreciated that there may be various combinations of fuel trains and multiple fuel sources within a given fuel train.
[0011] It is another aspect of the present invention to utilize a combination of one-way valves (e.g., check valves, flappers valves, etc.) and one or more reservoirs to ensure the uninterrupted supply of fuel to an engine. Some embodiments may maximize the use of a gaseous primary fuel from a first fuel train and utilize a liquid tertiary fuel from a second fuel train to provide uninterrupted fuel flow to the engine. Check valves positioned before a fuel tee that combines the fuel trains ensure that fuel does not flow from the fuel tee back into the fuel trains. The liquid fuel in the second fuel train is vaporized and regulated to a pressure that is above the maximum pressure of the engine such that the engine could run solely on the tertiary fuel if needed. A primary check valve is positioned in the first fuel train with a cracking pressure set to the minimum pressure that the engine can run on the primary fuel. This primary check valve will cut off the flow of primary fuel below a predetermined threshold to prevent a substandard performance from other components in the system. With this configuration, if the pressure of the primary fuel is greater than the maximum pressure of the engine, then only the primary fuel is used. If the pressure of the primary fuel begins to drop below the maximum pressure of the engine, then the tertiary fuel enters the fuel tee to supplement the primary fuel. If the pressure of the primary fuel falls below the cracking pressure of the primary check valve, then the flow of the primary fuel is completely shut off and the engine must rely on the tertiary fuel. However, there is a lag between when the flow of the primary fuel stops and when the tertiary fuel can meet the demands of the engine. Therefore, a fuel reservoir may be positioned downstream of the primary check valve to store an amount of primary fuel that prevents interruption of fuel to the engine.
[0012] It is a further aspect of certain embodiments of the present invention to provide a system for blending multiple sources of gaseous fuel that samples the blended fuel downstream of a mixing point. By knowing the properties of the various gaseous fuels beforehand, an algorithm may combine the gaseous fuels in a certain proportion. However, variations in the qualities of the gaseous fuels may affect the theoretical properties of the blended fuel. Therefore, some embodiments of the present invention may sample the blended fuel downstream of the mixing point to optimize the blended fuel in real time.
[0013] It is another aspect of various embodiments of the present invention to provide a system for blending multiple sources of fuel that optionally includes a pop-off valve. Some embodiments of the present invention may include devices such as heaters to increase the pressure of one or more gaseous fuels or convert liquid fuels into a gaseous state. A pop-off valve may bleed off pressure in case the pressure of the fuels rises to a dangerous level. However, in the absence of a pop-off valve, the pressure regulators may be more robust to handle any surges in pressure. Embodiments of the present invention contemplate systems, methods, and devices that include a pop-off valve and systems, methods, and devices that do not include a pop-off valve.
[0014] It is yet another aspect of various embodiments of the present invention to provide a novel manifold or fuel tee that mixes different types of gaseous fuel. Embodiments of the present invention may comprise a plurality of fuel trains wherein each fuel train is connected to a different fuel supply (i.e., propane, natural gas, etc.). Uneven or stratified mixtures of multiple gaseous fuels result in uneven and inconsistent burning during operation of the engine. To ensure an even and uniform burn during operation, the manifold of the instant invention thoroughly blends the plurality of fuel types. Embodiments of the manifold may utilize baffles, turbulent air flow, application of a vortex motion, or any other mixing means discussed elsewhere herein.
[0015] One specific embodiment of the present invention is a fuel blending system for an engine positioned proximate to a producing hydrocarbon wellbore, comprising: (a) a fuel tee interconnected to a first fuel train and a second fuel train, the fuel tee receiving a primary fuel from the first fuel train and a tertiary fuel from the second fuel train, the fuel tee interconnected to an engine having a maximum pressure; (b) the first fuel train comprising: (1) a primary fuel input from the producing hydrocarbon wellbore supplying the primary fuel; (2) a first primary check valve having an opening pressure that is less than the maximum pressure of the engine; (3) a fuel reservoir positioned downstream from the primary check valve comprising a reservoir volume to store a predetermined volume of the primary fuel; (4) a second primary check valve having an opening pressure that is less than the opening pressure of the first primary check valve; (c) the second fuel train comprising: (1) a tertiary fuel input supplying a liquid tertiary fuel; (2) a vaporizer configured to vaporize the liquid tertiary fuel into a gaseous tertiary fuel, the vaporizer regulating a pressure of the gaseous tertiary fuel to a tertiary pressure, the tertiary pressure is greater than the maximum pressure of the engine; and (3) a tertiary check valve having an opening pressure that is less than the tertiary pressure.
[0016] Some embodiments of the present invention may comprise addition components. In some embodiments the second fuel train may further comprise a second vaporizer configured to vaporize the liquid tertiary fuel into the gaseous tertiary fuel, the second regulating the pressure of the gaseous tertiary fuel to the tertiary pressure, wherein an outlet tee combines outlets of the vaporizers, wherein the outlet tee is located less than approximately 6″ from the outlets of the vaporizers. In some embodiments, the tertiary check valve is located approximately equidistant between the outlet tee and the fuel tee. In various embodiments, the fuel tee is located less than approximately 10″ from a regulator of the engine.
[0017] In some embodiments, the various opening pressures and regulated pressures may be set to specific ranges of pressures. For example, the opening pressure of the first primary check valve may be between approximately 6 and 8 PSI. Further, the opening pressure of the second primary check valve and/or the tertiary check valve may be between approximately 0.036 and 0.073 PSI. The tertiary pressure may be approximately 0.073 PSI greater than the maximum pressure of the engine. The predetermined volume of the primary fuel may be approximately 1000 cubic inches. In some embodiments, the primary fuel is natural gas and the tertiary fuel is liquid propane.
[0018] Yet another specific embodiment of the present invention is a method of blending fuel for an engine, comprising: (a) providing a fuel tee that interconnects a first fuel train and a second fuel train to an engine having a maximum pressure; (b) providing, by a primary fuel input, a primary fuel for the first fuel train, the primary fuel having a pressure; (c) passing the primary fuel through a primary check valve having a cracking pressure that is less than the maximum pressure of the engine; (d) passing the primary fuel through a fuel reservoir having a reservoir volume, wherein the reservoir volume stores a reserve of the primary fuel; (e) providing, by a tertiary fuel input, a liquid tertiary fuel for the second fuel train; (f) vaporizing, by a vaporizer, the liquid tertiary fuel into a gaseous tertiary fuel, the vaporizer regulating the gaseous tertiary fuel to a tertiary pressure, the tertiary pressure is greater than the maximum pressure of the engine; (g) closing the primary check valve when the pressure of the primary fuel is less than the cracking pressure of the primary check valve; and (h) drawing the reserve of the primary fuel into the fuel tee and into the engine.
[0019] In some embodiments, the present invention further comprises passing the primary fuel through a second primary check valve having a cracking pressure that is less than the cracking pressure of the primary check valve; and passing the tertiary fuel through a tertiary check valve having a cracking pressure that is less than the tertiary pressure. In various embodiments, the cracking pressure of the second primary check valve may be between approximately 0.036 and 0.073 PSI, and the cracking pressure of the tertiary check valve may be between approximately 0.036 and 0.073 PSI. In some embodiments, the cracking pressure of the primary check valve may be between approximately 6 and 8 PSI. In various embodiments, the tertiary pressure may be approximately 0.073 PSI greater than the maximum pressure of the engine. In some embodiments, the reservoir volume may be approximately 1000 cubic inches.
[0020] Various embodiments of the present invention may comprise additional steps. For example, embodiments may further comprise vaporizing, by a second vaporizer, the liquid tertiary fuel into the gaseous tertiary fuel, the second vaporizer regulating the gaseous tertiary fuel to the tertiary pressure, wherein an outlet tee combines outlets of the vaporizers, wherein the outlet tee is located less than approximately 6″ from the outlets of the vaporizers. In various embodiments, the tertiary check valve may be located approximately equidistant between the outlet tee and the fuel tee. In some embodiments, the fuel tee may be located less than approximately 10″ from a regulator of the engine. In some embodiments, the primary fuel is natural gas and the tertiary fuel is liquid propane, and the engine is positioned proximate to a producing hydrocarbon wellbore.
[0021] Another specific embodiment of the present invention is a fuel blending system for an engine positioned proximate to a producing hydrocarbon wellbore, comprising (a) a fuel tee interconnected to a first fuel train and a second fuel train, the fuel tee receiving a primary fuel from the first fuel train, and the fuel tee receiving a tertiary fuel from the second fuel train, the fuel tee interconnected to an engine having a maximum pressure, wherein the fuel tee is located less than approximately 10″ from a regulator of the engine; (b) the first fuel train comprising (1) a primary fuel input supplying the primary fuel; (2) a first primary flapper valve having a cracking pressure that is between approximately 6 and 8 PSI; (3) a fuel reservoir comprising a reservoir volume to store a reserve of the primary fuel, wherein the reservoir volume is approximately 1000 cubic inches; (4) a second primary flapper valve having a cracking pressure that is between approximately 0.036 and 0.073 PSI; (c) the second fuel train comprising (1) a tertiary fuel input supplying a liquid tertiary fuel; (2) a first vaporizer configured to vaporize the liquid tertiary fuel into a gaseous tertiary fuel, the first vaporizer regulating a pressure of the gaseous tertiary fuel to a tertiary pressure, the tertiary pressure is approximately 0.073 PSI greater than the maximum pressure of the engine; (3) a second vaporizer configured to vaporize the liquid tertiary fuel into the gaseous tertiary fuel, the second regulating the pressure of the gaseous tertiary fuel to the tertiary pressure, wherein an outlet tee combines outlets of the vaporizers, wherein the outlet tee is located less than approximately 6″ from the outlets of the vaporizers, and (4) a tertiary flapper valve having a cracking pressure that is between approximately 0.036 and 0.073 PSI, wherein the tertiary flapper valve is located approximately equidistant between the outlet tee and the fuel tee.
[0022] One specific embodiment of the present invention is a fuel blending system for a hydrocarbon-based, fuel-powered engine having a minimum operating pressure and a maximum operating pressure, comprising a first fuel train comprising: (a) a primary fuel input supplying a primary fuel having a pressure; (b) a primary regulator for regulating the pressure of the primary fuel, wherein the primary regulator has a minimum output pressure and a maximum output pressure, wherein the minimum output pressure of the primary regulator is less than the minimum operating pressure of the engine, and the maximum output pressure of the primary regulator is greater than the maximum operating pressure of the engine; (c) a sensor for detecting the regulated pressure of the primary fuel below a predetermined threshold; a second fuel train comprising: (d) a tertiary fuel input supplying a liquid tertiary fuel; (e) a vaporizer configured to convert the liquid tertiary fuel to a gaseous tertiary fuel having a pressure; (f) a tertiary regulator for regulating the pressure of the tertiary fuel, wherein the tertiary regulator has a minimum output pressure and a maximum output pressure, wherein the minimum output pressure of the tertiary regulator is less than the minimum operating pressure of the engine, and the maximum output pressure of the tertiary regulator is greater than the maximum operating pressure of the engine, and a mixing point that combines the primary fuel and the tertiary fuel such that the combined fuel has a pressure greater than the predetermined threshold and within the minimum operating pressure and the maximum operating pressure of the engine.
[0023] Another specific embodiment of the present invention is a method of combining fuels for a hydrocarbon-based, fuel-powered engine having a minimum operating pressure and a maximum operating pressure, comprising: (a) providing a first fuel train having a primary fuel input, the primary fuel input supplying a primary fuel having a pressure; (b) regulating the pressure of the primary fuel using a primary regulator, wherein the primary regulator has a minimum output pressure and a maximum output pressure, wherein the minimum output pressure of the primary regulator is less than the minimum operating pressure of the engine, and the maximum output pressure of the primary regulator is greater than the maximum operating pressure of the engine; (c) detecting, by a sensor, the regulated pressure of the primary fuel below a predetermined threshold; (d) providing a second fuel train having a tertiary fuel input, the tertiary fuel input supplying a liquid tertiary fuel; (e) passing the liquid tertiary fuel through a vaporizer to convert the tertiary fuel to a gaseous tertiary fuel having a pressure; (f) regulating the pressure of the tertiary fuel using a tertiary regulator, wherein the tertiary regulator has a minimum output pressure and a maximum output pressure, wherein the minimum output pressure of the tertiary regulator is less than the minimum operating pressure of the engine, and the maximum output pressure of the tertiary regulator is greater than the maximum operating pressure of the engine; and (g) combining the primary fuel and the tertiary fuel at a mixing point such that the combined fuel has a pressure greater than the predetermined threshold and within the minimum operating pressure and the maximum operating pressure of the engine.
[0024] Yet another specific embodiment of the present invention is a fuel blending system for a hydrocarbon-based, fuel-powered engine having a minimum operating pressure and a maximum operating pressure, comprising a first fuel train comprising: (a) a primary fuel input supplying a primary fuel having a pressure; (b) a primary regulator for regulating the pressure of the primary fuel, wherein the primary regulator has a minimum output pressure and a maximum output pressure, wherein the minimum output pressure of the primary regulator is less than the minimum operating pressure of the engine, and the maximum output pressure of the primary regulator is greater than the maximum operating pressure of the engine, wherein the maximum operating pressure of the engine is a maximum pressure for 120% of the gaseous fuel required to power a maximum load of the engine; (c) a secondary fuel input supplying a secondary fuel having a pressure; (d) a secondary regulator for regulating the pressure of the secondary fuel, wherein the secondary regulator has a minimum output pressure and a maximum output pressure, wherein the minimum output pressure of the secondary regulator is less than the minimum operating pressure of the engine, and the maximum output pressure of the secondary regulator is greater than the maximum operating pressure of the engine; (e) a fuel tee that combines the secondary fuel with the primary fuel to supplement the primary fuel; (f) a sensor for detecting the regulated pressure of the primary fuel below a predetermined threshold; a second fuel train comprising: (g) a tertiary fuel input supplying a liquid tertiary fuel; (h) a vaporizer configured to convert the liquid tertiary fuel to a gaseous tertiary fuel having a pressure; (i) a tertiary regulator for regulating the pressure of the tertiary fuel, wherein the tertiary regulator has a minimum output pressure and a maximum output pressure, wherein the minimum output pressure of the tertiary regulator is less than the minimum operating pressure of the engine, and the maximum output pressure of the tertiary regulator is greater than the maximum operating pressure of the engine; and a mixing point that combines the primary fuel and the tertiary fuel such that the combined fuel has a pressure greater than the predetermined threshold and within the minimum operating pressure and the maximum operating pressure of the engine.
[0025] The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the present invention. The present invention is set forth in various levels of detail in the Summary of the Invention as well as in the attached drawings and the Detailed Description of the Invention and no limitation as to the scope of the present invention is intended by either the inclusion or non-inclusion of elements or components. Additional aspects of the present invention will become more readily apparent from the Detailed Description, particularly when taken together with the drawings.
[0026] The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth above or described in detail below.
[0027] The phrases “at least one,” “one or more,” and “and/or,” as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B, and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together.
[0028] Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.”
[0029] The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more,” and “at least one” can be used interchangeably herein.
[0030] 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. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof can be used interchangeably herein.
[0031] It shall be understood that the term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C. §112(f). Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials, or acts and the equivalents thereof shall include all those described in the summary of the invention, brief description of the drawings, detailed description, abstract, and claims themselves.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the Summary of the Invention given above and the Detailed Description of the drawings given below, serve to explain the principles of these embodiments. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein. Additionally, it should be understood that the drawings are not necessarily to scale.
[0033] FIG. 1 is a flow diagram of a fuel blending system according to embodiments of the present invention; and
[0034] FIG. 2 is a flow diagram of another fuel blending system according to embodiments of the present invention.
[0035] Similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a letter that distinguishes among the similar components. If only the first reference label is used, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
[0036] A list of the various components shown in the drawings and associated numbering is provided herein:
[0000]
Number
Component
2
Fuel Blending System
4
First Fuel Train
6
Primary Fuel Input
8
Secondary Fuel Input
10
Primary Pressure Regulator
12
Secondary Pressure Regulator
14
Fuel Tee
16
Fuel Reservoir
16a
Inlet Diverter
18
Knock Down Pressure Regulator
20
Shut Off Valve
22
Pressure Check Valve
24
Engine Pressure Regulator
26
Second Fuel Train
28
Tertiary Fuel Input
30
Tertiary Fuel Vaporizer
32
Mixing Point
34
Vacuum Source
36
First Primary Check Valve
38
Filter
40
Second Primary Check Valve
42
Tertiary Check Valve
44
Engine Fluid
DETAILED DESCRIPTION
[0037] The present invention has significant benefits across a broad spectrum of endeavors. It is the Applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed. To acquaint persons skilled in the pertinent arts most closely related to the present invention, a preferred embodiment that illustrates the best mode now contemplated for putting the invention into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary embodiment is described in detail without attempting to describe all of the various forms and modifications in which the invention might be embodied. As such, the embodiments described herein are illustrative, and as will become apparent to those skilled in the arts, may be modified in numerous ways within the scope and spirit of the invention.
[0038] Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning.
[0039] Various embodiments of the present invention are described herein and as depicted in the drawings. It is expressly understood that although the figures depict systems and methods for blending gaseous fuels, the present invention is not limited to these embodiments.
[0040] Now referring to FIG. 1 , a fuel blending system 2 comprising a first fuel train 4 and a second fuel train 26 is provided. The first fuel train 4 comprises a primary fuel input 6 and a secondary fuel input 8 . The fuel inputs 6 , 8 connect the fuel blending system 2 to any gas or liquid fuel supply. For example, in one embodiment the primary fuel input 6 connects the fuel blending system 2 to a natural gas distribution line, and the second fuel input 8 connects the fuel blending system 2 to a vaporized propane supply.
[0041] In the event that one or both of these inputs 6 , 8 contain liquid fuel, one or more vaporizers may be used to completely vaporize the liquid fuel. In some embodiments, the one or more vaporizers may produce gaseous fuel having a pressure that is equal to or greater than the maximum operating pressure of the engine. In various embodiments, the maximum operating pressure is a maximum pressure for 120% of the gaseous fuel required to power a maximum load of the engine, which allows the system 2 to retain continuity of operation for all applicable code & requirements for prime rated and continuous duty rated prime movers. In other embodiments, the maximum operating pressure of the engine is a maximum pressure between approximately 100% and 150% of the gaseous fuel required to power a maximum load of the engine.
[0042] The fuel inputs 6 , 8 may be any ball valve, solenoid, check valve, butterfly valve, or any other device that controls the flow of gas or liquid. Other aspects of the connection between the fuel blending system 2 and the gas or liquid fuel supply such as conduit sizing, location, application, material, etc. may be dictated by Application & Installation Guides for a given manufacturer of a fuel powered engine or a given model of fuel powered engine. It will be appreciated that there may be a variety of embodiments of fuel inputs 6 , 8 that connect the fuel blending system 2 to a gas or liquid fuel supply while complying with constraints imposed by the manufacturer or other entity.
[0043] Next, fuel from the primary fuel input 6 flows into a primary regulator 10 , and fuel from the secondary fuel input 8 flows into the secondary regulator 12 . The regulators 10 , 12 control or step down the pressure of the incoming fuel. Some embodiments of the present invention may utilize a direct-operated, spring-loaded, pressure reducing regulator such as a Big Joe regulator. However, in various embodiments a variety of other regulators may control or step down the pressure of the incoming fuel.
[0044] Various embodiments of the present invention may operate in the absence of a pop-off valve placed in series with the regulators 10 , 12 . In these configurations, a maximum input pressure of the regulators 10 , 12 can be rated ten times (1000%) higher than the anticipated maximum fuel source pressure if all regulations were to fail.
[0045] After the regulators 10 , 12 control or step down the pressure of the incoming fuel, the regulators 10 , 12 output the fuel at a certain pressure. In various embodiments, the minimum output pressure of the regulators 10 , 12 can meet or fall short of the minimum operating pressure of the fuel-powered engine. In some embodiments, the minimum operating pressure may be established when the engine is starting, idling, jogging, or in a “no load” condition. Further in various embodiments, the maximum output pressure of the regulators 10 , 12 can meet or exceed the maximum operating pressure of the engine, which as noted above, may be a maximum pressure for 120% of the gaseous fuel required to power a maximum load of the engine, which allows the system 2 to retain continuity of operation for all applicable code & requirements for prime rated and continuous duty rated prime movers.
[0046] In some embodiments of the present invention, the regulators 10 , 12 have different output pressure ranges. For example, in one embodiment the primary regulator 10 has a higher output pressure than the secondary regulator 12 , which allows for greater use of the primary fuel. Adjustable regulator output pressure allows a user or electronic system to mixing different portions of the primary and secondary fuels to meet a condition (e.g., emission standards) or to achieve an optimization (e.g., cost). More specifically, a sensor or sensors may monitor the downstream pressure of, for example, the primary fuel to determine if the pressure of the primary fuel falls below a predetermined threshold. If this is the case, then the system 2 may allow a secondary fuel that has a pressure that is higher than the predetermined threshold to supplement the primary fuel until the supplemented primary fuel also has a pressure that is higher than the predetermined threshold. The same supplement function may be applied to parameters such as BTU energy content. If the BTU energy content falls below a predetermined threshold, a secondary fuel with a BTU energy content that is higher than the predetermined threshold may supplement the primary fuel until the supplemented primary fuel has a BTU energy content that is higher than the predetermined threshold.
[0047] After exiting the regulators 10 , 12 , the fuel from the primary source and the fuel from the secondary source mix together at a fuel tee 14 . This fuel tee 14 may simply be “tee” junction pipe fitting that combines two pipe inputs into a single pipe output. A “tee” junction pipe fitting ensures that conduit from each regulator 10 , 12 is equidistant, but in other embodiments the conduits are not equidistant. In some embodiments, the fuel tee 14 may comprise baffles or other similar features to impart a vortex motion on the two fuels to ensure a more complete blend. In various embodiments, the fuel tee 14 is positioned three times the length of the regulators' 10 , 12 fittings or more away from the regulators 10 , 12 to prevent back pressuring. Other embodiments may have other positioning constraints to comply with any Application & Installation Guides or other regulations.
[0048] Next, a conduit guides the supplemented fuel from the fuel tee 14 to a fuel reservoir 16 and/or a scrubbing system. One or more sensors may be positioned on or in the conduit to sample various parameters of the supplemented fuel such as mixture percentage, pressure, BTU, or any other parameter discussed elsewhere herein. If one or more of the parameters falls below a predetermined threshold, then the supplemented primary fuel may be supplemented by yet another secondary or tertiary fuel to meet all relevant parameter thresholds. Examples of sensors include oxygen sensors, mass spectrometers, water sensor, MAP sensor, COSA 9600 BTU Analyzer, ECT sensor, air/fuel sensor, crankshaft position sensor, vehicle speed sensor, variable reluctance sensor, turbine speed sensor, air flow meter, flow sensor, gas meter, mass flow sensor, among many other sensors.
[0049] The fuel blending system 2 may optionally comprise a fuel reservoir 16 and/or a scrubbing system. The fuel reservoir 16 stores blended fuel in the event of an interruption in supply or pressure such that the fuel-powered engine operates continuously. A scrubbing system of the fuel reservoir 16 removes traces of liquid droplets from the supplemented primary fuel to protect downstream equipment from damage and/or failure. When the supplemented primary fuel first enters the scrubbing system it encounters an inlet diverter 16 a which causes an initial separation of the liquid droplets from the supplemented primary fuel such that the heavier liquid droplets descend while the gas rises. The scrubbing system may also comprise a vaned mist extractor to further reduce liquid droplets. The scrubbing system may remove liquid droplets by gravity, centrifugal force, impingement, or any other method that separates liquid droplets from the supplemented primary fuel.
[0050] Next, the supplemented primary fuel enters a knock down pressure regulator 18 to more precisely tune the pressure of the supplemented primary fuel and control the engine operating pressure. The knock down pressure regulator 18 may be any pressure regulator that steps down pressure or otherwise controls pressure.
[0051] After the knock down pressure regulator 18 , the supplemented primary fuel flows through a shut off valve 20 , which provides the ability to completely shut down the flow of fuel during an emergency. The shut off valve 20 may be operatively connected to an electronic monitoring system such that upon an event trigger, the shut off valve 20 will stop the flow of the blended fuel. In other embodiments, the shut off valve 20 impedes or redirects the flow of the supplemented primary fuel so as to not damage any upstream components with back pressure.
[0052] Next, the supplemented primary fuel enters a check valve 22 to control any possible back pressure issues and ensure that the supplemented primary fuel flows in one direction. In various embodiments, the check valve 22 is set at 5% above an operating pressure required to run 120% of the fuel required to power the engine's maximum load, which allows the engine to maintain continuity of operation for all applicable code and requirements for prime rated and continuous duty rate prime movers. In some embodiments, the check valve 22 is set at approximately 5% above an operating pressure required to run 100% of the fuel required to power the engine's maximum load. In other embodiments, the check valve 22 is set approximately 5-10% above an operating pressure required to run 120% of the fuel required to power the engine's maximum load.
[0053] After the check valve 22 , the supplemented primary fuel enters an engine pressure regulator 24 to more precisely tune the pressure of the supplemented primary fuel and control the engine operating pressure. In other embodiments, the engine pressure regulator 24 may be any pressure regulator that steps down pressure or otherwise controls pressure.
[0054] Again referring to FIG. 1 , the fuel blending system 2 comprises the second fuel train 26 . In this embodiment, a tertiary fuel input 28 connects the fuel blending system 2 to any gas or liquid fuel supply. For example, in one embodiment the tertiary fuel input 28 connects the fuel blending system 2 to a liquid propane system. The tertiary fuel input 28 may be any ball valve, solenoid, check valve, butterfly valve, or any other device that controls the flow of gas or liquid. Other aspects of the connection between the fuel blending system 2 and the gas or liquid fuel supply such as conduit sizing, location, application, material, etc. may be dictated by Application & Installation Guides for a given manufacturer of a fuel powered engine or a given model of fuel powered engine. In various embodiments, the tertiary fuel input 28 may connect the fuel blending system 2 to a gas or liquid fuel supply while complying with constraints imposed by the manufacturer or other entity.
[0055] Next, the fuel flows through one or more tertiary fuel vaporizers 30 , which convert fuel in a liquid state to fuel in a gaseous state. The tertiary fuel vaporizers 30 such as feed-back systems and feed out systems may utilize external heat sources to help convert the fuel to a gaseous state. Feed-back systems allow pressure to build up in a vessel before the fuel continues downstream while feed-out system simply add heat as the fuel passes by. The tertiary fuel vaporizer 30 may output the fuel at a certain pressure. In various embodiments, the minimum output pressure of the tertiary fuel vaporizer 30 can meet or fall short of the minimum operating pressure of the fuel-powered engine. In some embodiments, the minimum operating pressure may be established when the engine is starting, idling, jogging, or in a “no load” condition. Further in various embodiments, the maximum output pressure of the tertiary fuel vaporizer 30 can meet or exceed the maximum operating pressure of the engine, which as noted above, may be a maximum pressure for 120% of the gaseous fuel required to power a maximum load of the engine, which allows the system 2 to retain continuity of operation for all applicable code & requirements for prime rated and continuous duty rated prime movers.
[0056] After the liquid fuel has been converted to gas, the fuel passes through a shut off valve 20 . As described elsewhere herein, the shut off valve 20 provides the ability to completely shut down the flow of fuel during an emergency. The shut off valve 20 may be operatively connected to an electronic monitoring system such that upon an event trigger or emergency, the shut off valve 20 with stop of the flow of the blended fuel. In other embodiments, the shut off valve 20 impedes or redirects the flow of the blended fuel so as to not damage any upstream components.
[0057] A tertiary regulator may be included in the second fuel train 26 to step down or control the pressure of the tertiary fuel when the vaporizer 30 does not regulate the pressure of the gaseous tertiary fuel. After the tertiary regulator controls or steps down the pressure of the incoming fuel, the tertiary regulator outputs the fuel at a certain pressure. In various embodiments, the minimum output pressure of the tertiary regulator can meet or fall short of the minimum operating pressure of the fuel-powered engine. In some embodiments, the minimum operating pressure may be established when the engine is starting, idling, jogging, or in a “no load” condition. Further in various embodiments, the maximum output pressure of the tertiary regulator can meet or exceed the maximum operating pressure of the engine, which as noted above, may be a maximum pressure for 120% of the gaseous fuel required to power a maximum load of the engine, which allows the system 2 to retain continuity of operation for all applicable code & requirements for prime rated and continuous duty rated prime movers.
[0058] The fuels from the first fuel train 4 and the second fuel train 26 meet at a mixing point 32 or a fuel tee. Similar to the fuel tee 14 , the mixing point 32 mixes the supplemented primary fuel from the first fuel train 4 and the gaseous fuel from the second fuel train 26 into a combined fuel that is then supplied to the engine. In some embodiments, the mixing point 32 comprises baffles or other similar features to impart a vortex motion on the two fuels to ensure a more complete blend.
[0059] In the embodiment depicted in FIG. 1 , the engine is a vacuum source 34 , which draws in the combined fuel from the mixing point 32 . In this embodiment, the engine is a fuel-powered, reciprocating engine that employs a vacuum type carburetion system to entrain fuel. It will be appreciated that there may be a variety of engine types that utilize a gaseous blended fuel.
[0060] The various components of the fuel blending system 2 may be optimized for performance. As described elsewhere herein, a primary fuel may need to be supplemented in order to hit certain targets or predetermined thresholds. In one embodiment, the primary fuel is natural gas which is subject to pressure fluctuations and quality issues. Other fuels such as liquid propane may supplement the primary fuel, but liquid propane is more expensive than natural gas. Thus, the fuel blending system 2 logic may be as follows: use liquid propane to ensure the fuel blend is above a minimum or predetermined pressure and to ensure the fuel blend is above a minimum or predetermined quality profile (e.g., based on energy content, carbon content, etc.). After the thresholds are met, then optimized for price, which in this case means use as much natural gas as possible. It will be appreciated that there may be fuel blending systems 2 that use different fuel parameters to set different thresholds and to pursue various optimizations.
[0061] In one embodiment, the fuel blending system 2 may be combined with a Caterpillar Model G3306 Engine with vacuum carburetion. The engine would be located proximate to field gas and a liquid propane tank, which may be equipped with a vaporizer and/or heating element for the supplemental aspect of the fuel blending system 2 . The propane tank may comprise a stand pipe to draw liquid from the tank for a secondary fuel train of the fuel blending system 2 . During operation, if the field gas operated at 18 psi and was inconsistent or the field gas had a BTU value that was below threshold to operate the engine at full load, then a mixing point or manifold would supplement the field gas with vaporized propane. A blended sample would be collected and analyzed providing a blended BTU content with which the engine's A-Regulator and timing could be set, and later “fine-tuned” to meet emissions controls. The cost of consumption of propane would be reduced when compared to normal applications where the customer would have been forced to run solely on propane due to the inconsistent field gas pressure or quality.
[0062] Now referring to FIG. 2 , another embodiment of a fuel blending system 2 is provided. A fuel tee 32 interconnects a first fuel train 4 and a second fuel train 26 to an engine 34 , which may have a vacuum carburetion system to draw in fuel from the fuel tee 32 and the fuel trains 4 , 26 . Some engines may be naturally aspirated and thus have a substantially constant maximum intake pressure (or vacuum or draw). In other embodiments, the engine may be augmented, for example, with a turbo booster. In these embodiments, the maximum intake pressure would be the intake pressure associated with a maximum boost from the turbo booster.
[0063] The engine advantageously draws fuel from one or both fuel trains 4 , 26 to optimize a parameter such as cost, BTU energy content, or any other parameter discussed elsewhere herein. The system 2 in FIG. 2 is configured to maximize consumption of a primary fuel from the first fuel train 4 to optimize for cost. However, a second fuel train 26 provides a tertiary fuel to supplement the primary fuel in the event that there is an interruption in the supply of the primary fuel. In an exemplary real world application, the primary fuel may be field gas from a produce well, and the tertiary fuel is liquid propane. As explained in further detailed below, when the pressure of the primary fuel in the first fuel train 4 is greater than the maximum pressure of the engine 34 , then the engine draws only the primary fuel. When the pressure of the primary fuel drops below the maximum pressure of the engine 34 , the engine 34 draws both primary fuel and tertiary fuel. Finally, when the pressure of the primary fuel drops below a predetermined value, the engine 34 draws only the tertiary fuel.
[0064] The first fuel train 4 is supplied with a primary fuel from a primary fuel input 6 . In various embodiments, the primary fuel is natural gas or field gas in a gaseous state. The primary fuel passes through a first primary check valve 36 which has a cracking pressure set below the maximum pressure associated with the engine 34 . The first primary check valve 36 establishes the cut off pressure that changes the fuel mixture traveling into the engine 34 from a primary fuel/tertiary fuel blend to a tertiary only fuel. In some embodiments, the cracking pressure of the first primary check valve 36 is between approximately 6 and 8 PSI, which may represent the lowest pressure of primary fuel that the engine 34 may run on or the lowest pressure that other components of the system 2 may operate effectively.
[0065] Assuming the primary fuel has a great enough pressure, the primary fuel passes through the first primary check valve 36 into a fuel reservoir 16 . In some embodiments, this may be done via a 1″ National Pipe Thread with the first primary check valve 36 positioned as close as possible to the fuel reservoir 16 . As described above, the fuel reservoir 16 may comprise different components to help separate any residual liquid primary fuel from the gaseous primary fuel. The fuel reservoir 16 may also hold a reserve amount of the primary fuel to help with the transition between a primary fuel/tertiary fuel mixture to a tertiary fuel into the engine 34 . When the first primary check valve 36 ceases flow of the primary fuel, a reserve amount of primary fuel is needed as the tertiary fuel begins to exclusively supply the engine 34 . In some embodiments the reserve amount may be approximately 1000 cubic inches. One example of a fuel reservoir 16 is a PECPFacet Model 89. Next, the primary fuel may be passed through another filter 38 to remove any particulate matter from the primary fuel.
[0066] The primary fuel is then passed through a shutoff valve 20 that may control and stop the passage of primary fuel in the event of a pressure spike, thus saving the engine 34 from any damage. Lastly, the primary fuel may pass through a second primary check valve 40 before entering the fuel tee 32 . The second primary check valve 40 may be set to a relatively low cracking pressure to prevent the backflow of fuel from the fuel tee 32 back into the first fuel train 4 . The cracking pressure of the second primary check valve 40 may be set between approximately 0.036 and 0.073 PSI.
[0067] The second fuel train 26 is also interconnected to the fuel tee 32 , and the second fuel train 25 is supplied with a tertiary fuel from a tertiary fuel input 8 . In some embodiments, the tertiary fuel may be a liquid fuel such as liquid propane. The liquid tertiary fuel may first pass into one or more vaporizers 30 to vaporize the tertiary fuel into a gaseous state. In some embodiments, the tertiary fuel is transported into two vaporizers using a ⅜″ inner diameter pipe. In various embodiments, the vaporizers 30 are Impco Model E Vaporizers. The vaporizers 30 convert the liquid tertiary fuel to a gaseous tertiary fuel, and the vaporizers 30 may also regulate the pressure of the gaseous tertiary fuel as it exits the vaporizers 30 . In some embodiments, the tertiary fuel pressure is regulated higher than the maximum pressure of the engine 34 so that the system 2 could run exclusively off of the tertiary fuel if needed. In some embodiments, the pressure of the tertiary fuel is regulated to approximately 0.073 PSI greater than the maximum pressure of the engine 34 .
[0068] As shown in FIG. 2 , an engine liquid line 44 may be used to help vaporize the tertiary fuel. Engine liquids such as radiator coolant or oil may be siphoned off from the engine 34 to help deliver heat to the liquid tertiary fuel in the vaporizer 30 , which aids in the vaporization of the fuel to a gaseous state. This process also helps decrease the temperature of the engine liquid to help regulate various functions of the engine 34 .
[0069] As the tertiary fuel exits the vaporizers 30 , the outlet for each vaporizer 30 may be a ¾″ National Pipe Thread, and the two outlets are joined together at an outlet tee. In some embodiments, the outlet tee is positioned between approximately 4 to 6″ from the vaporizers 30 , and in various embodiments, the outlet tee is positioned less than 14″ from the vaporizers 30 . The tertiary fuel passes through a tertiary check valve 42 and a shut off valve 20 before entering the fuel tee 32 . The cracking pressure of the tertiary check valve 42 may be set between approximately 0.036 and 0.073 PSI. The tertiary check valve 42 may be positioned approximately equidistant between the outlet tee of the vaporizers 30 and the fuel tee 32 .
[0070] The fuel tee 32 mixes the fuels from the fuel trains 4 , 26 , if needed, and then delivers fuel to the engine 34 , wherein an engine regulator may be positioned between the engine 34 and the fuel tee 32 to tune the pressure of the fuel before entering the engine 34 . In some embodiments, the fuel tee 32 is positioned less than 10″ from the regulator of the engine 34 .
[0071] The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limiting of the invention to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments described and shown in the figures were chosen and described in order to best explain the principles of the invention, the practical application, and to enable those of ordinary skill in the art to understand the invention.
[0072] While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. Moreover, references made herein to “the present invention” or aspects thereof should be understood to mean certain embodiments of the present invention and should not necessarily be construed as limiting all embodiments to a particular description. It is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention, as set forth in the following claims.
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A device, system, and method are provided for blending multiple fuels in multiple states and optimizing the blended fuel for parameters including cost, energy content, pressure, etc. In a primary fuel/supplemental fuel system, the present invention allows a user to consume as much primary fuel as possible even if the primary fuel is hampered by inconsistent pressure or quality issue, thus ensuring a downstream engine runs continuously.
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FIELD OF THE INVENTION
This invention relates to an actuator for controlling a steering angle or a steering angle ratio of rear wheels relative to front wheels in a front and rear wheel steering device for a vehicle which variably controls the steering angle of the rear wheels according to certain conditions.
DESCRIPTION OF THE PRIOR ART
There have been a number of proposals to provide front and rear wheel steering devices particularly in the form of four wheel steering devices. For instance, Japanese Patent Application No. 53-163678 (Japanese Patent Laying-Open Publication No. 55-91457) corresponding to U.S. Pat. No. 4,313,514 filed by the Assignee of the present application, proposes a front and rear wheel steering device for a vehicle which steers the rear wheels in relation with the steering of the front wheels in the same phase relationship in high speed range and in the opposite phase relationship in low speed range. The steering angle ratio may be a continuous function relative to the vehicle speed. In this connection, the object of the control may be either the steering angle ratio of the rear wheels relative to the front wheels or the steering angle of the rear wheels itself.
Thus, a continuous control of the steering angle or the steering angle ratio of the rear wheels is performed according to this continuous function so that the function of the steering device may be favorable in both high speed and low speed ranges. Specifically, the minimum angle of turning and the inner radius difference of the vehicle are both drastically reduced and the maneuverability of the vehicle, particularly in low speed range, in driving the vehicle into a garage, driving the car through narrow and crooked alleys and making a U-turn are substantially improved with the additional advantage of improving the dynamic laterial response of the vehicle in high speed range.
However, in such a front and rear wheel steering device, if the control of the steering angle ratio is not properly performed for instance due to freezing of the steering angle ratio, the steering angle of the rear wheels may have substantial errors from an acceptable range of steering angle.
Generally speaking, in a front wheel steering device, the reaction which the front wheels receive from the road surface is allowed to be transmitted to the steering wheel so that the driving of the vehicle may be facilitated by obtaining a force which tends to return the front wheels to their straight positions from the caster angle given to the front wheels. However, as for the rear wheels, such action is not only unnecessary but may cause the inconvenience that the motion of the vehicle may be affected by interferences such as the irregularities of the road surface when the rear wheels are steered. Particularly in such a case, should the actuator fail for any reason, the rear wheels will be locked or frozen in the steered state and the driving of the vehicle may become extremely difficult.
SUMMARY OF THE INVENTION
In view of such inconveniences of the prior art, a primary object of this invention is to provide a manual means to restore an actuator for controlling the steering angle of the rear wheels to a neutral state.
Another object of the present invention is to provide such a manual means which will not hamper the normal action of the actuator.
According to the present invention such objects are accomplished by providing an actuator for controlling a steering angle of rear wheels relative to front wheels in a front and rear wheel steering device for a vehicle which variably controls the steering angle of the rear wheels according to certain conditions comprising: means for manually neutralizing the steering of the rear wheels.
According to a certain aspect of the present invention, the actuator drives a device for determining the steering angle ratio of the rear wheels relative to the front wheels.
Thus, by adding a manual steering angle ratio setting up means to a device for determining the steering angle ratio of the rear wheels, the steering angle ratio of the rear wheels may be restored for instance to zero even when the proper control of the steering angle ratio of the rear wheels is impossible.
According to another aspect of the present invention, the actuator directly steers the rear wheels.
Thus, by adding a manual steering means to the actuator for steering the rear wheels, the rear wheels may be restored to their neutral positions even when the proper control of the steering angle of the rear wheels has become impossible.
BRIEF DESCRIPTION OF THE DRAWINGS
Such and other objects and advantages of the present invention will be better understood with reference to the following description and the appended drawings in which:
FIG. 1 is a perspective view showing the general basic structure of a vehicle provided with an actuator for a front and rear wheel steering device according to this invention with the chassis of the vehicle removed;
FIG. 2 is a magnified perspective view of a rear wheel steering system of the embodiment of FIG. 1;
FIG. 3 is a magnified perspective view of a part of FIG. 2;
FIG. 4 (a), (b) and (c) are skeleton diagrams of the rear wheel steering system of FIG. 2, illustrating the working principle thereof;
FIG. 5 is a block diagram of the control structure of the embodiment of FIGS. 1 to 3;
FIG. 6 is a graph showing the steering angle characteristics of the embodiment of FIGS. 1 to 4;
FIG. 7 is a simplified perspective view showing a rear wheel steering device to which another embodiment of the actuator for steering the rear wheels according to this invention is applied; and
FIG. 8 is a general simplified perspective view of a rear wheel steering device to which a third embodiment of the actuator for steering the rear wheels according to this invention is applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now embodiments of this invention are described in the following with reference to the appended drawings.
As shown in FIG. 1, a steering column shaft 2 of a steering wheel 1 is joined into a rack and pinion type gear box 3, and a pair of tie rods 5 are connected to the two ends of a rack shaft 4 which meshes with a pinion gear (not shown in the drawings) integrally attached to the lower end of the steering column shaft 2. To the external ends of the tie rods 5 are connected a pair of knuckle arms 6 which support right and left front wheels 7, respectively, in such a manner that the front wheels 7 can be steered to the direction determined by the steering wheel 1 in the known manner.
A pinion shaft 8 extends from the gear box 3 to the rearward direction and an elongated linkage shaft 10 is connected to the rear end of the pinion shaft 8 by way of a universal joint 9. The pinion shaft 8 is provided with a pinion gear (which is not shown in the drawings) which meshes with the rack shaft 4. And an input shaft 12 (FIG. 2) is connected to the rear end of the linkage shaft 10 by way of another universal joint 11. This input shaft 12 is disposed along the laterally central line of the rear part of the vehicle and is rotatably supported by a bearing bracket 13 as best shown in FIG. 2.
Further, a swing shaft 15, which is described in greater detail in FIG. 2, is connected to the rear end of the input shaft 12 by way of a clevis 14, and a joint member 16 is loosely fitted over a middle portion of the swing shaft 15. The two lateral ends of the joint member 16 are connected to tie rods 25 by way of ball joints 26 respectively, and the joint member 16 is fixedly supported by a middle part of an arm member 17 which is arranged along the widthwise direction of the vehicle.
One end of the arm member 17 is connected to the vehicle body by way of a link member 18 and a link bracket 19 while the other end of the arm member 17 is connected to the vehicle body by way of link members 20 and 21 and a link bracket 22 in such a manner that the arm member 17 may be able to swing in a vertical plane which is perpendicular to the longitudinal direction of the vehicle. A pivot shaft 23 of the link member 21 on the side of the braket 22 can rotate integrally with the link member 21. The external ends of the tie rods 25 are connected to knuckle arms 28 which support rear wheels 27 as shown in FIG. 1.
A motor 31 is mounted in a part of the vehicle body located on the side of the other end of the arm member 17 and an output shaft of the motor 31 is fixedly provided with a worm gear 32 which in turn meshes with a sector gear 24 integrally mounted to the pivot shaft 23 of the link member 21. Thus, the rotation of the motor 31 will cause the rotational motion of the arm member 17.
According to this embodiment, since the advance angle of the worm gear 32 is selected to be smaller than the friction angle thereof, external force applied to the rear wheels will not drive the worm gear 32 by way of the sector gear 24 and the steering angle ratio of the rear wheels will not be affected by external factors such as the irregulatities of the road surface.
Furthermore, so that the steering angle ratio may be restored, for instance manually, to a neutral position even when the steering angle ratio is fixed to a certain value for instance due to a failure of the motor 31 for any reason, a hexagonal cross-section portion 36 is provided at an end of the output shaft of the motor 31, as best shown in FIG. 3, and the steering angle ratio of the rear wheels may be fixed to zero by engaging a separately stowed crank handle 37 with the hexagonal portion 36 and manually turning the output shaft of the motor 31.
It goes without saying that other engagement means may be used in place of the hexagonal portion 36. And, the crank handle 37 may also serve as a handle of a car jack.
Further, the vehicle is provided with a computer 33 which receives signals from a vehicle speed sensor 34 for detecting the vehicle speed and a position sensor 35 which detects the position of the pivot shaft 23 of the link member 21 and sends an appropriate control signal to the computer 33 according to the vehicle speed to control the rotation of the motor 31.
When the pivot point P of the joint member 16 coincides with the center O of the input shaft 12 as shown in FIG. 4 (a), the input shaft 12 and the swing shaft 15 rotate in a coaxial manner, and therefore the joint member 16 will not laterally swing and the tie rods 25 remain stationary so that only the front wheels 7 are steered and the rear wheels 27 are not steered at all, in the same manner as in a conventional vehicle.
When the link member 21 is downwardly rotated by the rotation of the motor 31 by way of the worm gear 32 and the sector gear 24 meshing therewith, the arm member 17 inclines with its left end down as shown in FIG. 4 (b). Due to this inclination of the arm member 17, the pivot point P is located below the axial center O and, if the input shaft 12 is rotated for instance in counter-clockwise direction by angle theta, the tie rods 25 move rightwardly as indicated by broken lines in FIG. 4 (b), to steer the rear wheels 27 in the direction opposite to the steering direction of the front wheels 7.
When the link member 21 is upwardly rotated by reverse rotation of the motor 31, the arm member 17 inclines with its left end up as shown in FIG. 4 (c). Due to this inclination of the arm member 17, the pivot point P is located above the axial center O and, if the input shaft 12 is rotated for instance likewise in counter-clockwise direction by angle theta, the tie rods 25 move leftward, as opposed to the previous case, as indicated by broken lines in FIG. 4 (c), to steer the rear wheels 27 in the same direction as the front wheels 7.
Now the control action of the above-described embodiment will be described in the following with reference to FIGS. 5 and 6.
FIG. 5 shows the functional structure of the computer 33. The vehicle speed signal detected by the vehicle speed sensor 34 is supplied to the computer 33 as a certain vehicle speed signal u. This vehicle speed signal u is converted into a predetermined steering angle ratio signal k 0 (=f(u)) by a conversion process (a).
The position sensor 35 detects the rotational position of the link member 21 which is proportional to the steering angle ratio in actual steering and the detected result is supplied to the computer 33 as an actual steering angle ratio k m . A relative difference delta k=k m -k 0 is obtained by a comparison process (b) from the actual steering angle ratio data k m and the predetermined steering angle ratio data k 0 . This difference delta k is supplied from the computer 33 to an output control device 38 as data corresponding to the correction of the steering angle ratio which is required to obtain the desired steering angle ratio. The output end of the output control device 38 is connected to the motor 31 and supplies thereto a control signal s corresponding to the difference delta k. Thus, the motor 31 is rotated in the direction which accomplishes the steering angle ratio according to the functional relationship shown in FIG. 6.
Thus, according to this embodiment, since a vehicle with a front and rear wheel steering device can be reduced to a conventional vehicle which can steer only the front wheels, should the front and rear wheel steering device fail for malfunction or other reasons, by manually reducing the steering angle ratio of the rear wheels for instance to zero, the reliability of the front and rear wheel steering device will be improved.
In the above-described embodiment, the various processes conducted in the computer 33 are executed by a certain program (software) stored for instance in a storage area of the computer 33, but it is possible to utilize electric circuitry having a similar functionality to perform the same processes. Further, this invention is also applicable to a front and rear wheel steering devices in which the front steering angle information is transmitted to the computer 33 as an electric signal.
FIG. 7 shows a second embodiment of the actuator for steering the rear wheels according to this invention. An electric motor 41 is fixedly secured to a portion of a vehicle body adjacent to a central position of a rear part of the vehicle, and a screw rod 42 is fixedly and coaxially secured to the output shaft of the motor 41. The screw rod 42 is threadingly engaged with an internal screw thread formed in a projection 43 of a slider 45. The slider 45 is supported by the vehicle body so as to be slidable along the lateral direction and is connected to internal ends of tie rods 46 by way of ball joints. The other ends or the external ends of the tie rods 46 are connected to knuckle arms 47 of rear wheels 48 likewise by way of ball joints. A portion 42a of hexagonal cross-section is formed at the free end of the screw rod 42.
Here, the lead angle of the thread of the screw rod 42 is selected to be smaller than the friction angle thereof and the rear wheels 48 may be steered by driving the slider 45 through the rotation of the screw rod 42 but the screw rod 42 would not be driven by an external force applied to the rear wheels 48.
The motor 41 is connected to a computer 49 carried by the vehicle and is driven so as to achieve a desired steering angle in the rear wheels 48 according to a certain control program. When the motor 41 is rotatively driven, the slider 45 moves laterally by way of the screw mechanism and the rear wheels 48 can be steered.
If the action of the motor 41 is impossible for any reason and the rear wheels 48 have become stationary with a certain steering angle, it may become difficult to drive the vehicle. Therefore, in such a case, a crank handle 40 may be engaged with the hexagonal portion 42a and the screw rod 42 may be turned in the necessary direction to restore and fix the rear wheels 48 to their neutral positions. It goes without saying that other engagement means may be used in place of the hexagonal portion 42a. And, the crank handle 40 may also serve as a handle of a car jack.
FIG. 8 shows a third embodiment of the actuator for steering the rear wheels according to this invention. The output shaft of a motor 51 is provided with a worm gear 52 which in turn meshes with a worm wheel 53 mounted to a pinion shaft 54 of a rack and pinion gear device 55. The two ends of a rack shaft of the rack and pinion gear device 55 are connected to internal ends of the rods 56, respectively, by way of ball joints and the other ends of the tie rods 56 are connected to knuckle arms 57 of the rear wheels 58, respectively, likewise by way of ball joints.
The motor 51 is connected to a computer 59 carried by the vehicle and is rotatively driven so as to achieve a desired steering angle of rear wheels 58 according to a predetermined control program. When the motor 51 is rotatively driven, the rear wheels 58 are steered by the motor 51 by way of the rack and pinion gear device 55 and the tie rods 56. In this embodiment also, the advance angle of the worm gear 52 is selected to be smaller than the friction angle thereof so that the rear wheels 58 will not be steered by the external force applied thereto by driving the motor 51.
In view of the case in which the motor 51 becomes stationary for a failure thereof while the rear wheels 58 are steered in either direction, a portion 52a with hexagonal cross-section is provided at an end of the output shaft of the motor 51 so that the rear wheels 58 may be manually restored to their neutral positions by engaging a separately stored crank handle 40 with the hexagonal portion 52a and manually turning the output shaft of the motor 51 to restore the rear wheels 58 to their neutral positions.
Thus, according to these embodiments, since a vehicle with a front and rear wheel steering device can be reduced to a conventional vehicle which can steer only the front wheels even when the function of the front and rear wheel steering device is terminated for malfunction and other reasons, by manually restoring the rear wheels to their neutral positions, the reliability of the front and rear wheel steering device will be improved.
Although the present invention has been shown and described with reference to the preferred embodiments thereof, it should not be considered as limited thereby. Various possible modifications and alterations could be conceived of by one skilled in the art to any particular embodiment, without departing from the scope of the invention.
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An actuator for steering the rear wheels in front and rear steering device for a vehicle in which the steering angle of the rear wheels can be manually neutralized should the actuator fail with the rear wheels steered to a certain angle. The actuator may be a type which either directly steers the rear wheels following command from control means or varies the state of means for setting up the steering angle ratio of the rear wheels. In either case, a preferably detachable handle may be engaged to an output end of power means of the actuator. Thus, the situation in which the rear wheels are frozen at a certain steering angle and the driving of the vehicle becomes difficult is safely avoided.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to washing machine agitators and more particularly pertains to a new washing machine scrubbing enhancement device for improving the cleaning efficiency of washing machines.
2. Description of the Prior Art
The use of washing machine agitators is known in the prior art. More specifically, washing machine agitators heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art includes U.S. Pat. No. 2,518,107; U.S. Pat. No. 5,692,581; U.S. Pat. No. Des. 379,298; U.S. Pat. No. 4,338,802; U.S. Pat. No. 5,651,278; and U.S. Pat. No. 4,151,320.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new washing machine scrubbing enhancement device. The inventive device includes a scrubber attachment comprising a channel member with side walls connected by a base wall forming a channel for gripping the sides of the agitator fins, and an adhesive applied to the side walls.
In these respects, the washing machine scrubbing enhancement device according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of improving the cleaning efficiency of washing machines.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of washing machine agitators now present in the prior art, the present invention provides a new washing machine scrubbing enhancement device construction wherein the same can be utilized for improving the cleaning efficiency of washing machines.
The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new washing machine scrubbing enhancement device apparatus and method which has many of the advantages of the washing machine agitators mentioned heretofore and many novel features that result in a new washing machine scrubbing enhancement device which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art washing machine agitators, either alone or in any combination thereof.
To attain this, the present invention generally comprises a scrubber attachment comprising a channel member with side walls connected by a base wall forming a channel for gripping the sides of the agitator fins, and an adhesive applied to the side walls.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new washing machine scrubbing enhancement device apparatus and method which has many of the advantages of the washing machine agitators mentioned heretofore and many novel features that result in a new washing machine scrubbing enhancement device which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art washing machine agitators, either alone or in any combination thereof.
It is another object of the present invention to provide a new washing machine scrubbing enhancement device which may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new washing machine scrubbing enhancement device which is of a durable and reliable construction.
An even further object of the present invention is to provide a new washing machine scrubbing enhancement device which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such washing machine scrubbing enhancement device economically available to the buying public.
Still yet another object of the present invention is to provide a new washing machine scrubbing enhancement device which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to provide a new washing machine scrubbing enhancement device for improving the cleaning efficiency of washing machine agitators.
Yet another object of the present invention is to provide a new washing machine scrubbing enhancement device which includes a scrubber attachment comprising a channel member with side walls connected by a base wall forming a channel for gripping the sides of the agitator fins, and an adhesive applied to the side walls.
Still yet another object of the present invention is to provide a new washing machine scrubbing enhancement device that minimizes the quantity of detergent required to clean a specified size and type of load.
Even still another object of the present invention is to provide a new washing machine scrubbing enhancement device that may reduce the total duration of a wash cycle.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIG. 1 is a schematic perspective view of a new washing machine scrubbing enhancement device according to the present invention installed on the agitator of a washing machine.
FIG. 2 is a schematic side view of the present invention shown exploded away from an agitator.
FIG. 3 is a schematic top view of the present invention.
FIG. 4 is a schematic side view of an optional embodiment of the present invention illustrating a plurality of grooves and ridges.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to the drawings, and in particular to FIGS. 1 through 4 thereof, a new washing machine scrubbing enhancement device embodying the principles and concepts of the present invention and generally designated by the reference numeral 10 will be described.
As best illustrated in FIGS. 1 through 4, the washing machine scrubbing enhancement device 10 generally comprises a clothes washing machine 20 and a scrubber attachment 30 .
The clothes washing machine 20 suitable for use with the scrubber attachment may comprise a housing 22 , a tub 24 , and an agitator 26 .
The housing 22 has an upper opening with a lid pivotally mounted to selectively close the upper opening.
The tub 24 is mounted in the housing 22 for rotation. The tub 24 has an opening located adjacent to the upper opening of the housing 22 for permitting items to be inserted and removed from the tub 24 through the upper opening of the housing 22 .
The agitator 26 has a central portion with an upper end and a lower end. The agitator 26 also has at least two fins 28 extending generally radially outward from the central portion between the upper and lower ends. Each fin 28 has an outer edge. In an embodiment, the outer edge of each fin 28 has a substantially triangular perimeter shape. However, other fin profiled, either relatively straight or even undulating, may be used with the invention.
The scrubber attachment 30 is mountable on one of the fins 28 of the agitator 26 . The scrubber attachment 30 comprises a channel member 32 and an adhesive member 38 .
The channel member 32 includes a pair of side walls 34 connected together by a base wall 36 to form a channel shape with an inner groove. The inner groove receives the outer edge of one of the fins 28 of the agitator 26 . The side walls 34 are biased towards each other such that the side walls 34 grip a portion of the fin 28 inserted into the interior groove of the channel member 32 . The channel member 32 has an inner surface lining the interior groove and an outer surface opposite the interior groove.
The adhesive member 38 may be applied to the side walls 34 for adhering the channel member 32 to the fin 28 of the agitator 26 . Suitably, the adhesive is water and detergent resistant.
In one embodiment of the invention, the outer surface has a plurality of raised bumps that contrast with the otherwise smooth surface of the agitator.
In a further embodiment, the outer surface has a plurality of raised ridges 40 with grooves in between. The ridges may be generally serpentine such that the grooves are curvy.
In use, each fin of the agitator has a scrubber attachment mounted to it. The scrubber attachments are secured by the adhesive member of the scrubber attachment and by the gripping action from the bias of the side walls. The machine is then used in the ordinary manner associated with clothes washing machines.
As to a further discussion of the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A washing machine scrubbing enhancement device for improving the cleaning efficiency of washing machines. The washing machine scrubbing enhancement device includes a scrubber attachment comprising a channel member with side walls connected by a base wall forming a channel for gripping the sides of the agitator fins, and an adhesive applied to the side walls.
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This is a National Phase Application filed under 35 U.S.C. 371 as a national stage of PCT/EP2012/068142, filed Sep. 14, 2012, and claims priority benefit from European Application No. 11181618.7, filed Sep. 16, 2011, the content of each of which is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
The present invention generally relates to a device for capturing fluids lighter than water escaping from an underwater source. The device is particularly useful for collecting and temporarily storing oil and/or gas escaping from an out-of-control deep-sea borehole. Additionally, the device could be used to capture pollutants, such as e.g. oil, oil products or chemical products, leaking from sunken tankers.
BACKGROUND ART
European Patent 1 524 186 discloses a device for collecting fluids having a density lower than that of the surrounding water and escaping from an underwater source. The device comprises an inverted-funnel-shaped dome placed over the underwater source for collecting the fluids escaped from the source and rising therefrom due to buoyancy. A transfer tube has a lower end in communication with the dome for transferring the collected fluids towards the surface. The device further comprises a submerged buffer reservoir, which is maintained at a predetermined depth under the surface, the submerged buffer reservoir being in communication with an upper end of the transfer tube for receiving the collected fluids. In the chamber of the submerged buffer reservoir, water will separate from the collected fluid due to the different densities, so that the submerged buffer reservoir acts as a separator, which concentrates the fluids in the upper part of the chamber.
U.S. Pat. No. 4,395,157 discloses an offshore drilling and pumping platform. The document shows collecting means in the form of an inverted funnel placed over an underwater oil and gas source, a riser tube for transferring the collected fluids towards a buffer reservoir maintained at the surface. The buffer reservoir comprises a chamber with an open bottom, into which the riser tube opens with its upper end. Gas is separated from oil in the buffer reservoir. GB 2066095 discloses a device for the recovery of fluids from underwater leaks. The device comprises a collection bell disposed above an underwater well, an open-bottom container arranged above the collection bell for storing the fluids and a riser, which reaches from the top of the collection bell into the interior of the container. At the upper end of the riser, a spiral flow channel is arranged for promoting the separation of the different phases of the fluids.
Document GB 2071020 relates to an apparatus for capturing and storing oil and gas flowing uncontrollably from an offshore well. The apparatus comprises an underwater liquid-gas separator to be positioned above a sea floor well blowout. Gas and oil is stored within a floatable storage vessel with an open bottom. Gas and oil are transported separately from the separator to the storage vessel, via an oil hose and a gas hose, respectively.
Document WO 81/01310 criticizes collecting means in the shape of sombreros (or inverted funnels), stating that it is difficult to transfer the mixture of oil and gas to the surface because of the proportional expansion of the escaping gas and pressure fluctuations due to gas bubbles. To address that problem, WO 81/0310 proposes to arrange a separator column on the seabed and to evacuate oil and gas though separate riser tubes.
The device disclosed in EP 1 524 186 has the advantage that it may be relatively easily installed above an underwater source. However, modifications to the system are necessary to enable it to deal with underwater sources releasing substantial amounts of gas, e.g. a borehole gone out of control, like the Mocondo well in the Gulf of Mexico in 2010. Indeed, as indicated by WO 81/01310, the expansion of the gas could destabilise the flow of the collected fluids up the riser tube. Nevertheless, a separation of the gas content from the other fluids at the seabed is undesirable, since it makes the system on the seabed more complicated. Valuable time may be lost in case of a blowout if a separator column as disclosed in WO 81/0310 must be put in place.
Technical Problem
It is an object of the present invention to provide an improved device for collecting and temporarily storing fluids rising from an underwater source, in particular with respect to the device's ability to handle fluids containing gas. This object is achieved by a device as claimed in claim 1 .
General Description of the Invention
According to the invention, a device for collecting and temporarily storing fluids escaping from an underwater source and having lower density than surrounding water comprises:
a collector, e.g. a deployable inverted funnel, for being placed over the underwater source for collecting the fluids escaping from the underwater source; a riser tube having a lower end in communication with the collector for transferring the collected fluids together towards the surface; and a buoyant buffer reservoir configured for being maintained submerged at a predetermined depth under the surface, the buffer reservoir comprising a chamber with an open bottom for storage of the fluids transferred by the riser tube.
The riser tube has flow restrictors comprising choke disks, arranged in its interior for restricting the flow of the fluids. The flow restrictors, which are arranged at regular or variable intervals all along the length of the riser tube, reduce the velocity of the fluids. Furthermore, the buffer reservoir has arranged in its chamber a separator vessel, into the interior of which the riser tube opens with its upper end for discharging the collected fluids. The separator vessel is configured for separating gas from the fluids discharged by the riser tube, e.g. as an oil/gas separator.
The invention is especially suited for collecting gas-containing fluids from underwater sources located at depths greater than 100 m, preferably greater than 200 m, below the sea level. As those skilled will appreciate, thanks to the invention, gas-containing fluids may be transferred from the seabed to the underwater buffer reservoir, without requiring separation of the gas fraction at the seabed. This greatly simplifies the structure to be deployed over the underwater source.
The device according to the invention may be used for prompt containment of deep sea off-shore well blowouts (like the 2010 Macondo well blowout in the Gulf of Mexico), collecting the leaking hydrocarbons (oil and gas) right at the seabed and separating the gas from the oil underwater, until a permanent solution (typically through side drills) is implemented, thus preventing dispersion of hydrocarbons on the sea surface and the resulting extended environment pollution. In addition, the device according to the invention could be used for the collection of natural gas from naturally occurring underwater methane sources (underwater methane volcanoes) for subsequent storage and exploitation with beneficial economic and environmental effects (methane is 20 times worse than CO 2 in terms of greenhouse effect).
When the device is in use, collected fluids are transferred to the submerged buffer reservoir, and not directly to the surface. In use, the collected fluid rises into the tube and penetrates into the chamber, where it accumulates. The buffer reservoir will thus store the fluids until it is emptied e.g. by a shuttle ship. Depending on the quantities of fluid leaking from the underwater source, the flow of fluid into the buffer reservoir may be continuous or not. So, as the fluid accumulates in the chamber, it also gradually replaces the initial, heavier water content of the chamber, which is expelled via the open bottom. In the chamber of the submerged buffer reservoir, the water will separate from the fluid due to the difference in specific weight, so that the submerged buffer reservoir also acts like a separator, which concentrates the fluids in the upper part of the submerged buffer reservoir. The gas content of the fluids is separated from the liquid fraction in the separator vessel, and, possibly, in the open-bottom storage chamber. The device preferably comprises one or more gas offtakes (each equipped with a gas evacuation valve) to (preferably continuously) remove the gas from the separator vessel and the chamber before it accumulates to too high an extent. The one or more offtakes are preferably connected to a gas holder (external to the submerged buffer reservoir) and/or a flare, so that gas can be collected or flared.
As the collected fluid is stored underwater, the fluid recovery procedure is almost completely independent of the weather conditions. Furthermore, there is no need for a surface platform or a pumping ship to be permanently installed at the vertical of the wreck for the collecting procedure.
The collector preferably comprises a deployable inverted funnel that has an apex opening to which the fluids escaping from the underwater source converge, and which is connected to the lower end of the riser tube.
The riser tube preferably has an inner diameter of at least 0.6 m, preferably of at least 1 m. Still more preferably, the inner diameter is comprised in the range from 1.5 m to 2.5 m.
Those skilled will appreciate that the device according to the invention is especially suited for collecting oil, gas etc. escaping from deep-sea sources. Accordingly, the riser tube has a length of at least 100 m, preferably of at least 200 m, and even more preferably of at least 400 m.
The buoyant buffer reservoir is preferably arranged at a predetermined depth under the sea surface that is comprised in the range from 20 m to 60 m, preferably in the range from 30 m to 50 m. This is considered sufficient for the submerged buffer reservoir not to be affected by weather-induced sea conditions. The buffer reservoir is also normally sufficiently deep to avoid collision with ships cruising in the area while being still easily accessible for recovering the stored fluid.
As indicated above, the flow restrictors comprise choke disks, i.e. perforated disks with multiple perforations restricting the cross section available for the flow to the area of the perforations. There may be one or more choke disks per flow restrictor.
The riser tube preferably comprises a plurality of tube modules joined to one another by connectors. Advantageously, the flow restrictors are arranged on the connectors. According to a preferred embodiment of the invention, the tube modules are made of polyethylene. The connectors are preferably made of steel.
Preferably, a plurality of anchors (e.g. suction anchors, dead weight blocks or free-falling torpedo-shaped anchors) for anchoring the collector to the ground are distributed at the periphery of the collector. The anchors allow keeping the collector over the underwater source in a predetermined position allowing a good fluid recovery. The anchors are preferably regularly distributed around the periphery of the collector in order to distribute the tensioning stresses approximately equally among the mooring lines (chains or cables, preferably synthetic, high-strength ropes) that connect the collector to the anchors. It is worthwhile noting that buoyancy of the buffer reservoir thus maintains the entire device for collecting and temporarily storing fluids under tension and keeps it in place. The buoyancy of the buffer reservoir thus plays a structural role in maintaining the system upright, but nevertheless sufficiently flexible to exhibit resiliency in case of difficult current conditions.
The connectors preferably comprise a plurality of mooring line guides regularly distributed about their circumference. The mooring lines may thus be passed along the riser tube and fixed to the buoyant buffer reservoir. The connectors are preferably rigid and arranged at regular intervals along the riser tube. The length of the tube modules (and the distance between two consecutive connectors) is advantageously comprised in the range from 10 m to 50 m. The length of the tube modules may be varied along the length of the riser tube, in accordance with deployment considerations.
Preferably, at least one of said flow restrictors comprises a valve, the valve comprising a first and a second perforated disk arranged coaxially with each other (and preferably also with the riser tube) in the riser tube. At least one of the disks is rotatable about the common axis with respect to the other disk in such a way that the overlap of the perforations of the first and the second disk, respectively, can be varied. Most preferably, the at least one rotatable disk comprises an actuator, which is accessible from the outside of the tube (e.g. by an ROV) and manipulation of which allows rotating the disk. Alternatively, the actuator is a remotely controlled actuator (e.g. a servodrive, a pneumatic or a hydraulic actuator).
BRIEF DESCRIPTION OF THE DRAWINGS
Further details and advantages of the present invention will be apparent from the following detailed description of a not limiting embodiment with reference to the attached drawings, wherein:
FIG. 1 is a schematic view of the device according to a preferred embodiment of the invention;
FIG. 2 is a schematic view of the separator vessel of the device of FIG. 1 ;
FIG. 3 is a perspective view of a riser tube portion;
FIG. 4 is a perspective view of a connector for connecting two consecutive tube modules;
FIG. 5 is a schematic top view of a first variant of the connector of FIG. 4 ;
FIG. 6 is a schematic top view of a second variant of the connector of FIG. 4 ;
FIG. 7 is a schematic illustration of the installation of the device of FIG. 1 .
DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows a preferred embodiment of a device 10 for collecting fluids in accordance with the invention. Reference sign 12 indicates an underwater borehole with a failed blowout preventer stack 14 . A slurry 16 of oil gas and water is projected upwardly from the borehole 12 .
The device 10 comprises a collector in form of a deployable inverted funnel 18 , a riser tube 20 and a buoyant underwater buffer reservoir 22 . The lower end 24 of the riser tube 20 is connected to an apex opening of the inverted funnel 18 . Under the action of buoyancy, the fluids escaping from the borehole 12 converge to the funnel apex and enter the riser tube 20 , wherein they ascend towards the sea surface 26 . The upper end 28 of the riser tube extends into the open-bottom chamber 30 of the buffer reservoir 22 , in which chamber it is connected to an oil/gas separator vessel 32 . As best illustrated in FIG. 2 , the mixture of oil, gas and water that is discharged into the separator vessel 32 by the riser tube 20 is deviated into a maze 34 , e.g. by a baffle 34 , wherein gas separates from the mixture and rises to the top of the separator vessel 32 . Oil and water leave the separator vessel 32 through openings 36 at the bottom of the separator vessel 32 and enter the open-bottom chamber 30 of the buffer reservoir 22 . In the chamber 30 , residual gas, water and oil segregate further, the gas and oil fractions moving up, the water fraction moving down. As oil and gas accumulate in the chamber 30 , they replace the initial seawater content, which is forced out through the open bottom. Gas accumulating in the upper portions of the separator vessel and the chamber 30 is evacuated, via a gas uptake 38 and a relief valve (not shown), to a flare 40 at the sea surface, where the gas is burnt off. Instead of burning the gas, it could also be led into a buoyant gas holder.
The collected fluids are not directly channelled to the surface 26 but stored in the submerged buffer reservoir 32 at a given depth, e.g. at 30 to 50 m below the sea surface (the distance is measured between the sea surface and the top of the reservoir). The recovery of the leaking oil and gas is thus not affected by weather conditions and particularly not affected by rough weather, which would otherwise hinder the recovery procedure.
As shown in FIG. 1 , the inverted funnel 18 is anchored to the seabed around the borehole 12 at several points, using anchors 42 (dead weight blocks or suction anchors, depending on the seabed).
Referring more specifically to the structure of the buffer reservoir 22 , it is advantageously designed so as to fulfil the function of a terminal buoy, in order to control the tension on the riser tube 20 . This is achieved using one or more ballast tanks 44 .
The submerged buffer reservoir is advantageously provided with a drainage port (not shown) for connection e.g. to a shuttle tanker for emptying the chamber 30 . The drainage port may consist of standard equipment through which the shuttle tanker, weather permitting, can recuperate the stored oil and/or gas rapidly, using standard offshore loading equipment and methods, typically by pumping. The frequency of emptying operations will depend on the prevailing weather and currents and on the leakage rate of the hydrocarbons.
The device 10 should be kept in place until a permanent solution, e.g. a side drill, has been implemented and the borehole 12 has been successfully clogged.
The dimensions of the riser tube 20 and the submerged buffer reservoir 22 should be chosen in accordance with the maximum expected leakage rate, the expected weather as well as the sea current patterns. The riser tube 20 is preferably of modular construction, as best illustrated in FIG. 3 . In the illustrated example, the riser tube 20 consists of tube modules 46 , preferably made of polyethylene, which are interconnected by connectors 48 . Tension along the riser tube 20 is transferred via the mooring lines 52 , which are guided substantially parallel to the riser tube 20 by means of mooring line guides 54 disposed on the middle stabilizing ring 50 of each connector 48 . In the illustrated embodiment, the riser tube has a diameter of 2 m and a wall thickness of 77 mm. The mooring lines are preferably synthetic, high-strength cables (e.g. made of Dyneema™ fibres) and may have a diameter of about 10 cm.
As shown in FIGS. 4 to 6 , the connectors 48 comprise a circular cylindrical sleeve portion 56 , which receives therein the end portions of the tube modules 46 to be connected together. A flow restrictor, in form of a perforated disk 58 (best shown in FIGS. 5 and 6 ) is arranged in the middle of the sleeve portion 56 . The flow restrictors 58 serve to control the flow velocity of the gas/oil/water mixture 16 , caused by the expansion of gas as it rises along the riser tube. The speed of ascension depends on the open cross section of the perforated disks 58 . Therefore, the total area and the distribution of the holes in each flow restrictor 58 may be chosen in accordance with a predetermined flow pattern. For instance, the perforated disk 58 ′ of FIG. 6 will restrict the flow to a greater extent than that of FIG. 5 , due to the absence of the central opening 60 (see FIG. 5 ). The flow restrictors are configured in such a way that the resulting flow velocities do not to cause problems to the structural stability of the riser tube 20 and do not prohibit the separation of gas, oil and water in the separator vessel 32 and the open-bottom chamber 30 .
The device 10 is preferably deployed using the following steps. First, the anchors 42 (e.g. 12 dead weight blocks or suction anchors) are lowered on the seabed by a work vessel 62 (see FIG. 7 ) equipped with a derrick, a crane or a winch of sufficient lifting capacity. The anchors 42 are arranged about the hydrocarbon source (the borehole 12 ) in substantially regular intervals on a circle having a predetermined diameter (e.g. 150 m to 200 m). Each of the anchors 42 comprises an eye, a suspension band, or the like, through which a rope can be passed. When the anchors 42 have been put in place, a small number (e.g. 3 to 6) of mooring lines 52 are deployed between selected, regularly spaced anchors and the work vessel 62 . The mooring lines are passed through the eyes provided on the anchors using one or more remotely operated vehicles 68 (ROVs). The front ends of the mooring lines are returned to the vessel 62 , where they are attached to winches 66 . At the sea surface, the unfolded collector 18 is lowered to the water and brought alongside the installation vessel 62 . It is connected to the rear ends of the deployed mooring lines 52 and the first, lowermost, section (module) of the riser tube. By operating the winches 66 , the unfolded collector 18 is lowered toward the seabed, while being guided and pulled by the mooring lines 52 already in place. The riser tube 20 is then built module by module, each time by placing a connector 48 on top of the previous module 46 , after which another tube module 46 is added. When the unfolded collector 18 is a predetermined distance away from the target, the buffer reservoir 22 (not shown in FIG. 7 ) is connected to the uppermost tube module. The collector 18 , the riser tube 20 and the buffer reservoir 22 are then lowered further, in such a way that the buffer reservoir 22 arrives at the predefined depth (about 30-50 m). Additional mooring lines 52 ′ are now disposed between the anchors 42 and the unfolded collector 18 , using again one or more ROVs 68 . One end of each additional mooring line 52 ′ is connected to the collector 18 . The other end is passed through the eye on the corresponding anchor 42 and attached to a lifting bag 70 . Finally, the collector 18 is unfolded. This is achieved by pulling on the mooring lines 52 ′ using the lifting bags 70 . The lifting bags 70 are preferably simultaneously inflated, so that the collector 18 unfolds substantially centrally above the target.
The device 10 presents many significant advantages. Firstly, it is very simple and does not require precise or elaborate manipulations or operations for its manufacturing or on-site deployment. Many of its components can be manufactured and assembled by non-specialised shipyards. The riser tube configuration is preferably implemented through a modular design, as illustrated in the example, adding operational flexibility and lowering the cost. The device 10 can be operated entirely by non-specialised personnel. Once in place, it does not require regular deep-sea operations or monitoring. The presence the submerged buffer reservoir makes the operations tolerant to rough surface weather conditions. The device is highly configurable, since both the riser tube and the buffer reservoir can be optimised (anchoring parameters, tube and buffer reservoir dimensions, tube/wire tensioning, depth of the buffer reservoir, eventual intermediate buoys etc). Last but not least, due to its flexibility of operation, the device can rapidly be installed in deep sea or shallower waters, and therefore can be a main tool in general intervention procedures to prevent major marine pollutions. Other advantages of the device are that it operation is entirely gravity driven. The device does not require any pumping or other complex operations that are very difficult and expensive at great depth. Furthermore, there is no need for pressure resistant pipes or containers nor for valves or other manipulations at great depths during operation. The technique does not interfere with the well nor does it pose any problems to possible side drills.
At the buffer reservoir, gas is separated and accumulates in the topmost part, where from it may be continuously evacuated towards the surface through special gas relief valves, to be collected or flared. The oil, separated by gravity from the water accumulates in the buffer reservoir, from where it is recovered in batches using standard offshore technology, when the weather permits it. The solicitations and conditions of the whole structure are essentially independent from weather at the surface. The capacity of the buffer reservoir may be chosen in accordance with the circumstances. It may amount to several thousand m 3 , e.g. preferably between 2500 m 3 and 25000 m 3 .
An important advantage of the system is that it may be installed without any intervention on the hydrocarbon source, e.g. the failed wellhead. The flux towards the surface can be further controlled by intervening all along the riser tube at the metallic junctions of the riser tube components even after the installation, using an ROV.
Thanks, in particular, to the strong anchoring at the seabed, the wide riser tube (diameter is typically about 2 m) and the separator vessel in the buffer reservoir, the device according to the invention can handle large flows of hydrocarbons (e.g. flows that occurred in the Deepwater Horizon accident). The capacity of the buffer reservoir has to be sufficiently high to be able to accumulate the oil and/or gas between the periodic off-loadings. It is expected that methane hydrate should not pose any problems to the system because the water/gas/oil mix can flow upwards right away through the large tube, much less prone to clogging than standard drilling risers. Moreover, the large diameter of the tube provides substantial thermal inertia to account for the cooling of the depressurizing gas. By the mentioned anchoring techniques, the collector may be anchored to the seabed so strongly that it can withstand several thousand tons of buoyancy forces. The tube walls may be made thick enough (77 mm in the above example) to resist against dynamic forces of expanding gas.
While a specific embodiment has been described in detail, those skilled in the art will appreciate that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.
LEGEND
10 Fluid collecting device
12 Underwater borehole
14 Blowout preventer stack
16 Slurry of oil, gas and water
18 Inverted funnel (collector)
20 Riser tube
22 Buoyant buffer reservoir
24 Lower end of riser tube
26 Sea surface
28 Upper end of riser tube
30 Open-bottom chamber
32 Oil/gas separator vessel
34 Baffle
36 Opening
38 Gas uptake
40 Flare
42 , 42 ′ Anchor
44 Ballast tank
46 Tube module
48 Connector
50 Stabilizing ring
52 , 52 ′ Mooring line
54 Mooring line guide
56 Sleeve portion
58 Perforated disk (flow restrictor)
60 Central opening
62 Work vessel
64 Tanker wreck
66 Winch
68 Remotely operated vehicle
70 Lifting bag
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A device ( 10 ) for collecting and temporarily storing fluids ( 16 ) escaping from an underwater source ( 12, 64 ) and having lower density than surrounding water includes a collector ( 18 ) placed over the underwater source for collecting the escaping fluids, a riser tube ( 20 ) for transferring the collected fluids together towards the surface; and a buoyant buffer reservoir ( 22 ) maintained submerged under the surface and having an open-bottom chamber ( 30 ) for storage of the fluids. The riser tube has flow restrictors has flow restrictors comprising choke disks ( 58, 58 ′) arranged in its interior for restricting the flow of the fluids. The flow restrictors are arranged along the length of the riser tube. The buffer reservoir has arranged in its chamber a separator vessel ( 32 ) for separating gas from the fluids. The riser tube opens into the interior of the separator for discharging the fluids.
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CROSS REFERENCE TO RELATED APPLICATIONS
This is a continuation-in-part of application Ser. No. 334,655, filed Dec. 28, 1981 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention deals with coke ovens and, in particular, with coke oven charging hole covers.
2. Description of the Prior Art
Coke ovens are conventionally filled with coal in preparation for the coking process through a plurality of charging holes located on the battery top. The removable covers for these charging holes have generally consisted of a single cast iron plate which rests on a frame surrounding the charging hole so as to form a peripheral gravity seal around the charging hole where the cover contacts the frame. These plates, however, are known to reach such high temperatures during the coking process that they may tend to warp, and if such warping does occur they may no longer form a gas tight seal with the charging hole frame. The escape of pollutants from inside the oven may, therefore, result. Furthermore, because heat is conducted more efficiently through these cast iron charging hole covers than through other sections of the oven roof, it is believed that this cast iron construction may be responsible for the occurrence of undersirable concentrations of heat directly above the covers. Various suggestions have been made for alleviating the above mentioned problems. U.S. Pat. No. 3,900,369, for example, proposes that a cover be constructed by bolting or otherwise fixing a preformed refractory plate section below an iron cover top section. While this cover would appear to reduce heat flow from inside the coke oven, it may, under certain circumstances, be preferable not to incur the costs involved in manufacturing a specially shaped, preformed refractory plate and fixing it to the iron cover. In particular, it is deemed advantageous from a cost perspective to use cast-in-place castable refractories in charging hole covers. It has been found, however, that conventional castable refractories may often not be sufficiently durable to be suitable for this use. Furthermore, even if a preformed refractory plate were used on a charging hole cover, such a charging hole cover might be subject to damage as it is continually removed from then replaced over the charging hole because of the relative brittleness of its refractory plate element. It is, therefore, the object of the present invention to provide a comparatively flexible, monolithic insulating charging hole cover which may be manufactured with relative ease and which does not require the production of any costly special refractory shapes.
SUMMARY OF THE INVENTION
The present invention is a charging hole cover which is comprised of a cylindrical wall which has a cover plate fixed to its upper terminal end and which is filled with a castable refractory insulating material which is preferably reinforced with fine stainless steel fibers. At the lower terminal end of the cylindrical wall there is a means for retaining the refractory in position, and a layer of material having superior insulating properties is interposed between the castable refractory and the cover plate. In another embodiment, an upper layer of refractory material is substituted for the central portion of the cover plate, and in still another embodiment a ferrous metal grate is cast into this upper refractory layer to make the cover magnetically liftable.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is further described in the accompanying drawings in which:
FIG. 1 is a plan view of a charging hole cover illustrating certain features of the present invention;
FIG. 2 is a cross sectional view of the charging hole cover of the present invention taken through line II-II in FIG. 1;
FIG. 3 is a view in vertical section of a charging hole cover representing a preferred embodiment of the present invention;
FIG. 4 is a view in vertical section of a charging hole cover representing a second embodiment of the present invention;
FIG. 5 is a view in vertical section of a charging hole cover representing a third embodiment of the present invention; and
FIG. 6 is a view in vertical section of a charging hole cover representing a fourth embodiment of the present invention.
DETAILED DESCRIPTION
A charging hole cover illustrating certain features of the present invention is shown in FIGS. 1 and 2. The cover is shown generally at numeral 10. This cover consists of a circular plate section 12 which is attached to the upper end of a generally cylindrical wall section 14. The wall section 14 is filled with an insulating castable refractory material 16. At the lower end of the wall section 14 there is a peripheral crimp 18 which retains the refractory material 16 in position. Preferably, the refractory material 16 is a refractory and metal composite and, in particular, a refractory matrix containing a random dispersion of fine steel stainless fibers of approximately one inch in length. Suitable steel fibers for inclusion in this matrix are trademarked or otherwise designated as RIBTEC 310 and are available from the Ribbon Technology Corporation of Canal Winchester, Ohio. These fibers provide flexibility to an otherwise generally brittle refractory system, and, along with the taper of the wall section 14 and the crimp 18, these fibers also help retain the refractory material within the wall section 14.
A suitable castable refractory for use in the cover 10 is sold by the General Refractories Company under the trademark LITE CAST® 30. This dry castable refractory is first mixed with three percent by volume of the RIBTEC 310 fibers. A minimum quantity of water is added to attain the desired plasticity for placement of the castable refractory in the inverted and attached plate section 12 and wall section 14. After this wet castable refractory has been placed in the inverted and attached plate section 12 and wall section 14, it may be satisfactorily dried by bringing its temperature up to 130° F. at the rate of 50° F. per hour. This temperature is maintained for one hour for each inch of thickness. At the rate of 50° F. per hour the temperature is then elevated to 600° F. and held at that temperature for one hour for each inch of thickness. Then at the rate of 100° F. per hour, the temperature should be brought up to 1,000° F. This heating should be continuous and uninterruped, and if excessive steaming should occur the firing rate should not be increased until the steam subsides.
The cover 10 is preferably magnetically lifted, but it may also be manually lifted with a hook. It will be seen from FIGS. 1 and 2 that a concave plate attachment 20 (shown in broken lines in FIG. 1) is fixed below the upper plate 12 so as to form a hook receiving space 22. A hook may be inserted into this hook receiving space through a slot 24 so as to engage an arcuate bar 26 (partially shown in broken lines in FIG. 1). This arcuate bar is attached at its ends to the concave attachment.
A preferred embodiment of the present invention is represented by the charging hole cover shown generally at numeral 28 in FIG. 3. The cover 28 consists of an upper lid 30 which is comprised of a steel plate 32 superimposed on a second steel plate 34. Peripherally surrounding the lid 30, there is a steel lip 36. The cover 28 also includes a stainless steel cylindrical wall section 38 which is filled with a layer of dense insulating fiber reinforced refractory 40 and a layer of less dense insulating board 42. The fibers used in the refractory 40 are of the RIBTEC 310 kind described above in connection with the cover 10. The insulating board 42 may be of a type sold by the Johns-Mansville Corporation under the designation Type 103 and the trademark CERA FORM®. It will be appreciated that the addition of the insulating board 42 to the cover enhances the overall insulating ability of the cover, but that such a material could probably not be used in this cover alone since it is subject to impregnation and consequential degradation by carbon particles found inside the charging hole. Since the dense refractory 40 resists carbon impregnation, it may be used to shield the insulating board and permit its interior use in the cover. A plastic liner 43 is emplaced between the refractory 40 and the insulating board 42. A stainless steel plate or foil may also be substituted for the plastic liner 43. It is believed that such a plate or foil would tend to reflect radiant heat downwardly back into the charging hole. Welded to the cylindrical wall 38 there is a wire mesh as at 44, which helps retain the refactory 40 in the cover. It will be understood that the refractory may also be adequately held in the cylindrical wall section by means of a lower terminal crimp on the wall section as is shown at 18 in FIG. 1 and/or by means of a downward and inward taper of the cylindrical wall section as is also shown in FIG. 1. Hence, a wire mesh fixed to the cylindrical wall, a lower terminal crimp on the cylindrical wall section or a downward and inward taper of the wall or any combination of two or more of these elements is considered to be a suitable means for retaining the fiber reinforced castable refractory material inside the cylindrical wall section. The cover 28 is preferably lifted magnetically, but it will also be observed that it is equipped with a hook receiving space 46 and a hook engaging bar 48 so as to facilitate its lifting by manual means. After the insulating board 42 has been emplaced in the cylindrical wall 38, it is covered with the plastic liner 43. The castable refractory is then mixed as was described above and the cylindrical walls are partially filled to the level of the wire mesh. After the refractory has been curred in the manner described above, the mesh is welded to the cylindrical wall. The cylindrical wall is then filled with mixed refractory which is subsequently also cured in the manner described above. It will also be understood that the mesh may be welded to the cylindrical wall section before any wet castable refractory is emplaced in the cylindrical wall section, and that after the mesh has been fixed to the wall section the wall section may then be completely filled with wet castable refractory which is then cured.
Referring to FIG. 4, a cover 50 representing a second embodiment of the present invention is illustrated. This cover has a steel lid 52 which is welded to a steel cylindrical wall 54 which is, itself, filled with a layer of dense fiber reinforced insulating castable refractory 56 and a layer of lightweight castable refractory 58. Preferred fibers for reinforcement are RIBTEC 310 steel fibers. A lightweight castable refractory which is preferred for use in this cover is sold by the General Refractories Company under the trademark or designation LITE CAST® 50 LI. It will be appreciated that this lightweight castable refractory conducts heat less readily than does the denser castable refractory, but that it is also more susceptible to carbon impregnation than the more dense refractory. Hence the use of adjoining layers of these refractories allows for an enhanced insulating effect while still preventing damage due to carbon impregnation. The lightweight castable refractory 58 is not fiber reinforced, and there is a plastic liner 59 between the two layers of refractory. A stainless steel plate or foil may be substituted for the plastic liner 59. A wire mesh 60 is also welded to the cylindrical wall 54 to help retain the refractory layers therein. The light weight refractory is cured and covered with the plastic liner before the denser castable refractory is emplaced in the cylindrical walls. The cover 50 is preferably magnetically lifted, but it may also be lifted manually by means of its hook receiving space 62 and hook engaging bar 64.
A cover representing a third embodiment of the present invention is shown in FIG. 5 generally at numeral 66. This cover 66 has a steel lip 68 and a cylindrical wall 70 with a lower shoulder ring 72. It is filled with a lower layer of dense fiber reinforced insulating castable refractory 74, an intermediate layer of lightweight castable refractory 76 and an upper layer of dense fiber reinforced castable refractory 78. Between these layers of refractory are plastic liners 80 and 82. Stainless steel plates or foils may be substituted for the plastic liners 80 and 81. Welded to the cylindrical wall 70 there is a wire mesh as at 84. The cover 66 is preferably vacuum lifted but it may also be manually lifted by means of hook receiving space 86 and hook engaging bar 88.
Referring to FIG. 6 there is illustrated still another embodiment of the present invention, a cover generally illustrated at numeral 90 has a generally cylindrical tapered cast iron side wall 92 which is characterized by an upper lip 94 and a lower shoulder ring 96. Cover 90 is filled with a layer of dense fiber reinforced insulating refractory material 98 and a layer of lightweight insulating castable refractory material 100. Interposed between these two refractory layers is a plastic liner 102. Additionally, a wire mesh 104 is welded to the wall 92 and cast into the refractory 98 to retain the refractory in the cover. A sufficient amount of a ferrous metal material such as steel grating 106 is also cast into the layer of lightweight reinforced cast refractory 100 so that the cover 90 can be lifted magnetically. It will also be appreciated that the cover shown in FIG. 5 may also be rendered magnetically liftable by similarly casting a steel grating or some other sufficient amount of a ferrous material into the upper layer of dense fiber reinforced castable refractory 78. Alternate manual lifting of cover 90 is facilitated by hook receiving space 108 and bar 110.
It will, therefore, be understood that there has been described a flexible insulating coke oven charging hole cover which may be manufactured quickly and at a relatively low cost. Although the invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made only as an example and that the scope of the invention is defined by what is hereafter claimed.
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A coke oven charging hole cover which includes a cylindrical wall section and a lower horizontal layer of a cast-in-place castable refractory material which is relatively dense and which contains a random dispersion of fine stainless steel fibers or similar fibers. A layer of an insulating material such as insulation board or a lightweight castable insulating refractory material is superimposed over the dense refractory material to enhance the overall insulating effect while avoiding damage due to carbon impregnation. A means for holding the refractory in the wall section such as a wire mesh which is fixed to the wall section and cast into the lower layer of the refractory is also provided.
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FIELD OF THE INVENTION
The present invention relates to secondary loop refrigeration, and in particular, to a method and apparatus using secondary loop cooling for controlling temperature in a series circuit of refrigeration devices having differing operating temperature requirements.
BACKGROUND OF THE INVENTION
The cooling system for commercial and retail establishments generally comprise a remotely located primary unit that is individually connected to the various cooling loads or zones therein, such as air conditioning, low temperature freezer units, and mid-temperature refrigeration units. Such arrangements in a typical supermarket refrigeration system oftentimes require hundreds or thousands of pounds of refrigerant charge in addition to thousands of feet of refrigerant lines. Additionally, plural primary units may be employed, however, each conditioned area nonetheless requires individual connection.
The problems associated with the above approaches have been further complicated by changes in the permissibility and availability of direct expansion refrigerants commonly used for such systems. Certain chlorofluorocarbons and perfluoroalkanes are being phased out because of their environmental impact. To the extent obtainable, the cost of such refrigerants are increasing markedly making the cost of the installed system considerably more expensive. Certain non-chlorinated low temperature and medium temperature refrigerants have been developed as alternatives, however, they tend to be even more costly. Other high temperature direct expansion refrigerants, such as R-134a, are more moderate in cost, but are not effective in direct expansion cooling systems below air conditioning. temperatures.
The foregoing problems have prompted refrigeration equipment manufacturers to propose the use of secondary liquid cooling. Therein, a primary condensing unit is closely coupled to a direct expansion heat exchanger. The refrigerant for the primary system may be selected based on performance, and because of the shorter supply lines the cost thereof is reduced. The direct expansion heat exchanger is coupled to a secondary system using a liquid secondary refrigerant. The secondary refrigerant is pumped through individual secondary lines to the liquid chilling coils in. various temperature control zones, such a refrigerated displays, walk-in coolers and the like.
One such system is disclosed in U.S. Pat. No. 5,713,211 to Sherwood. Therein, a liquid secondary refrigerant is directed in a secondary cooling loop from a primary-secondary heat exchanger to a series of display cases and pumped back to the heat (exchanger. Only a single zone, of the many zones typically found in commercial applications, is covered in the secondary loop. The secondary loop is not operative to provide coil defrosting.
Another approach is disclosed in U.S. Pat. No. 5,524,442 to Bergman et. al. wherein a secondary refrigeration loop employs an open loop air stream that directly impinges a product to be cooled. The secondary loop return air system is directed to a secondary heat exchanger interfaced with a primary refrigeration loop.
A plurality of secondary refrigeration loops using a single refrigerant are disclosed in U.S. Pat. No. 5,318,845 to Dorini et. al. and U.S. Pat. No. 5,138,845 to Mannion et. al. Therein, the return lines of the primary refrigeration are fed in parallel as the inlet lines to the secondary cooling loads and the secondary return lines are connected with the primary inlet lines. Control systems are provided with each cooling load to control temperature and flow rates. While providing some localization of lines, a single refrigerant charge for the cooling demands of the generally similar temperature demands of the various units of the system.
A further approach is disclosed in U.S. Pat. No. 5,042,262 to Gyger et. al. wherein second closed loop system is operative to transfer heat from a single heat sink using carbon dioxide as a secondary refrigerant.
It is apparent from the above that such secondary loop designs have not focused on the major problems associated with plural refrigerant systems, i.e. consolidation of the high cost/high performance primary refrigerant loop and a secondary loop capable of handling plural cooling zones of the type found in supermarkets, cold storage facilities, hospitals, industrial plants, hotels, shopping centers, and like locations requiring cooling, refrigeration and heating. By focusing on parallel exchanges, high fluid volume cost, high equipment costs, and power consumption for fluid transfer remain a problem.
SUMMARY OF INVENTION
The present invention addresses and overcomes the aforementioned problems and limitations by providing a secondary refrigeration system incorporating a continuous series of progressively increasing temperature zones in a single secondary cooling loop. Therein, a secondary fluid is interfaced with the primary system and has the fluid feed line connected in parallel to a plurality of cooling loads having the highest cooling demands, such as freezer units. The return lines of the first loads are combined and fed to a second zone of cooling loads having the next highest cooling demand, such as refrigerated displays. Thereafter the second zone return lines are fed back to the heat exchanger or to subsequent zones in a similar manner, such as air conditioning equipment.
Such design eliminates the need for individual piping for each zone thereby reducing refrigerant, equipment, power consumption and piping costs. Moreover, the heat exchanger may be bypassed for defrosting the coils in the zones wherein the temperature rise from the line loading will warm the coils sufficiently for defrosting, while upon completion of defrosting, the system may be quickly returned to operative status. Furthermore, the aforementioned design permits the use of low cost non-chlorinated fluids operative in the liquid phase providing the requisite viscosity, specific heat, thermal conductivity, and environmental acceptability while providing efficient heat transfer within temperatures ranging from −40° F. to +80° F.
Accordingly, it is an object of the present invention to provide a secondary cooling system having reduced material, equipment and operating costs in conditioning a plurality of cooling zones.
A further object of the invention is to provide a plurality of increasing temperature zones that are serially connected in a secondary cooling loop.
Another object of the invention is to provide secondary cooling loop system using environmentally acceptable high performance refrigerants in a liquid phase with chilling coils in a series connection of increasing temperature zones.
Yet another object of the invention is to provide a liquid secondary refrigeration loop connecting a plurality of cooling zones wherein the loop may be quickly and conveniently disabled allowing the latent heat from the units to raise the temperature of the fluid sufficiently for defrosting purposes.
DESCRIPTION OF DRAWINGS
The above and other objects and advantages of the present invention will become apparent upon reading the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic diagram of a serial banked secondary refrigeration system in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings for the purpose of describing a preferred embodiment of the present invention and not for limiting same, FIG. 1 shows a refrigeration system 10 for a facility having a plurality of cooling zones or loads to be maintained respectively at differing temperatures.
The system 10 includes a primary refrigeration system 12 for transferring heat in a primary loop 14 to an external environment using a primary refrigerant, and a secondary loop refrigeration system 20 for transferring heat from the cooling zones in a secondary loop 22 to the primary refrigeration system 12 using a secondary refrigerant. The system 10 is suitable for installation in a supermarket setting and will be described with reference thereto. However, it will become apparent that the system may be beneficially utilized in other multiple zone venues including without limitation cold storage facilities, hospitals, refrigerated industrial plants, hotels, shopping centers, laboratories, prisons, schools and industrial, institutional, commercial and residential spaces requiring temperature control at varying levels in multiple zones.
The primary refrigeration system 12 may be any suitable commercially available design comprising typically a remotely located compressor unit (not shown), located (external of the facility and typically on the roof thereof, having inlet lines 30 communicating with a multiple stage direct-expansion evaporator 32 having; stages 32 a , 32 b and 32 c ; and a return line 34 returning to the compressor unit. A suitable primary refrigerant for the primary loop would be R-22, R-404A or R-507. The evaporator 32 is preferably located proximate the compressor unit in order to minimize the length of the primary loop 12 and the primary refrigerant charge, but with convenient access to the cooling zones, to be controlled.
As described below in greater detail, the secondary refrigeration system 20 is connected with cooling zones or loads including a low temperature units 40 , such as freezers maintained in the operating range of about −40° F. to +9° F., medium temperature units 42 maintained in the operating range of about +10° F. to +38° F., and air conditioned units 44 maintained in the operating range of about +39° F. to +80° F. Plural units are illustrated for each zone, however, it will be appreciated that the number of units and zones will vary depending on the requirements of a particular facility.
The secondary refrigeration system includes an inlet line 50 leading to the evaporator 32 , an exit line 52 leading from the evaporator 32 to a coolant reservoir 54 . An expansion tank 56 having a pressure relief valve 57 is connected to the reservoir 54 by line 58 . The reservoir 54 is connected with branched check valve 60 , 62 through exit line 64 that includes a pressure regulator 66 . Refrigerated fluid from the reservoir 54 flows past check valve 60 to a supply pump 70 . The supply pump 70 is effective for maintaining flow and pressure conditions through the temperature zones and may be either a constant volume or constant pressure pump depending on the overall needs of the cooling system. At various locations as illustrated by the unnumbered solid circles, isolation valve may be provided for temporarily isolating discrete sections of the system.
The secondary refrigerant flows from the pump 70 through line 72 to a low temperature inlet manifold 74 having parallel inlet lines respectively communicating with freezer units 40 a , 40 b , 40 c , and bypass valve 76 . The outlet lines of the freezer units include temperature control valves 78 communicating in parallel with the exit line of valve 76 with a low temperature exhaust manifold 80 . In a conventional manner, the valves 78 are individually effective to maintain desired temperature conditions in the units 40 in a well known manner. The bypass valve 76 may be stepped or continuous varied by appropriate controls to maintain volumetric flow conditions in the secondary loop 22 sufficient for the overall needs of the system 10 . Additionally, the intake manifold 74 and the units 40 may include isolation valves, as illustrated, for removing the units from operation for service, replacement and the like.
The exhaust manifold 80 of the low temperature units 40 is connected by intermediate line 82 with a mid-temperature intake manifold 84 having inlets communicating with the mid-temperature units 42 a , 42 b , 42 c , 42 d and bypass valve 86 . The outlet lines of the refrigerator units include temperature control valves 90 communicating in parallel with the exit line of valve 86 with a mid-temperature exhaust manifold 92 . In a conventional manner, the valves 90 are individually effective to maintain desired temperature conditions in the refrigeration units 42 in a well-known manner. The bypass valve 86 may be stepped or continuous varied by appropriate controls to maintain volumetric flow conditions in the secondary loop 22 sufficient for the overall needs of the system 10 . Additionally, units 42 may include isolation valves for removing the units from operation for service, replacement and the like.
The exhaust manifold 92 of the mid-temperature units 42 is connected by intermediate line 94 with a high-temperature intake manifold 96 having inlets communicating with the air conditioning units 44 a , 44 b , 44 c , 44 d and bypass valve 98 . The outlet lines of the air conditioning units include temperature control valves 100 communicating in parallel with the exit line of valve 98 with an air conditioning exhaust manifold 102 . In a conventional manner, the valves 100 are individually effective to maintain desired temperature conditions in the air conditioning units. The bypass valve 96 may be stepped or continuous varied by appropriate controls to maintain volumetric flow conditions in the secondary loop 22 sufficient for the overall needs of the system 10 . Additionally, units 44 may include isolation valves for removing the units from operation for service, replacement and the like.
The exhaust manifold 102 is connected by line 104 to the inlet of a three-way defrost valve 110 . One outlet line from the valve 110 is fluidly connected between check valve 60 and supply pump 70 . The other outlet line from defrost valve 110 is fluidly (connected between check valve 62 and circulation pump 112 that has an outlet connected with the inlet line 50 to the heat exchanger 32 . A further isolation circuit 120 , illustrated by the dashed lines, may be included.
It will thus be appreciated that the three sets of cooling loads are serially connected in the secondary loop 22 , with parallel flow across the individual units in each stage. Such arrangement avoids the need for individual fluid connections with each stage, thereby reducing equipment, installation and refrigerant costs. Further, by operating the secondary loop in the liquid phase, numerous non-chlorinated, lower cost refrigerants may be employed. In particular, R-134a, while compatible with direct expansion systems is surprisingly effective in the fluid stages of the present invention providing an operational range from about −40° F. to +80° F. Other refrigeration fluids suitable for the secondary system include: glycol solutions, propylene glycol, ethylene glycol, brines, inorganic salt solutions, potassium solutions, potassium formiate, silicone plymers, synthetic organic fluids, eutectic solutions, organic salt solutions, citrus terpenes, hydrofluouroethers, hydrocarbons, chlorine compounds, methanes, ethanes, butane, propanes, pentanes, alcohols, diphenyl oxide, biphenyl oxide, aryl ethers, terphenyls, azeotropic blends, diphenylethane, alkylated aromatics, methyl formate, polydimethylsiloxane, cyclic organic compounds, zerotropic blends, methyl amine, ethyl amine, ammonia, carbon dioxide, hydrogen, helium, water, neon, nitrogen, oxygen, argon, nitrous oxide, sulfur dioxide, vinyl chloride, propylene, R400, R401A, R402B, R401C, R402A, R402B, R403A, R403B, R404A, R405A, R406A, R407A, R407B, R407C, R407D, R408A, R409A, R409B, R410A, R410B, R411A, R411B, R412A, R500, R502, R503, R504, R505, R506, R507A, R508A, R508B, R509A, R600A, R1150, R111, R113, R114, R12, RR22, R13, R116, R124, R124A, R125, R143A, R152A, R170, R610, R611, sulfur compounds, R12B1, R12B2, R13B1, R14, R22B1, R23, R32, R41, R114, R1132A, R1141, R1150, R1270, fluorocarbons, carbon dioxide, solutions of water, and combinations of the above fluids.
Operation of the Secondary Fluid Cooling System
With the primary system operating, the pumps 70 and 112 are started to circulate the secondary refrigerant in the secondary loop 22 . The capacity of the secondary loop 22 will be dependent on the cooling loads for the individual stages and the capacity of the evaporator 32 . Generally the entry. temperatures for the secondary refrigerant are −40 F to 0 F for the freezer stage, +1 F to +30 F for the refrigeration stage, and +34 F to +50 F for the air conditioning stage. Passing through the first stage, the secondary refrigerant will experience a temperature rise based on the demand thereat, however, the entrance temperature and flow at the second stage for handling the refrigeration requirements in the refrigeration units. Similarly, the conditions presented to the air conditioning units will be sufficient to handle the load requirements for this stage.
Operation of the Defrost Cycle
From time to time, the cooling, coils at the units may experience a frost or ice buildup limiting the cooling performance of the units. The secondary cooling system of the present invention may be quickly reconfigured to initiate a defrost cycle therefor. Such a cycle may be initiated by switching the position of the defrost valve 110 to the defrost position routing the fluid from line 104 to line 113 . This results in plural flow paths. First, circulation of the fluid will be maintained between the reservoir 54 and the evaporator 32 by pump 112 thereby maintaining a supply of cooled refrigerant for immediate use after the defrost cycle. Second, a loop will be established bypassing the evaporator 32 and reservoir such that the temperature rise in the secondary refrigerant experienced at the air conditioning stage will circulate through the freezer and refrigerator coils thereby defrosting and deicing the associated units. Upon completion of the defrost cycle, the valve 110 is reversed and refrigerated fluid is immediately circulated in the secondary loop for quickly restoring refrigerated operating conditions.
The above description is intended to be illustrative of the preferred embodiment, and modifications and improvements thereto will become apparent to those in the art. Accordingly, the scope of the invention should be construed solely in accordance with the appended claims.
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A secondary loop refrigeration system includes plural refrigeration zones serially connected in a secondary cooling loop using a liquid refrigerant in increasing order of operating temperatures, the secondary cooling loop being in heat exchange relationship with a primary cooling loop using direct expansion refrigerants. The primary cooling loop may be selectively isolated allowing the latent heat of the units in the zones to increase the circulating temperature of the secondary refrigerant sufficient to defrost the cooling coils.
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This application is a continuation of and claims priority to abandoned U.S. patent application Ser. No. 10/935,879, entitled “High Stiffness Flexure,” filed on Sep. 8, 2004 now abandoned.
BACKGROUND
The present invention relates to flexures, and more particularly to a high stiffness flexure and a process of making a high stiffness flexure.
A flexure is a flexible mechanical member connecting two bodies. They may be used as a special bearing or hinge to guide the linear motion of one or both of the bodies, such as a stage. A properly designed flexure is extremely stiff in every direction except the direction of motion. A major benefit of a flexure guided stage is the complete lack of friction, since no part is moving against another. Further, there is no backlash in a flexure stage. Most flexure systems are designed to guide motion linearly, although rotary flexures also exist. A flexure system can be constructed to be stiff or compliant in any number of allowed axes. A simple linear flexure is a strip of metal, or other strong material, that is securely attached at one point to one body and securely attached to a second body at another point. In a well designed flexure, the strip is made rigid for most of its length, but is weakened so that it can bend in short segments next to the attachment points.
An inherent limitation of a flexure is its limited motion. Since a flexure is actually a bending beam, its motion is limited by its limited flexural strength. Increased range of motion is allowed by increasing the length of the flexure, but this compromises other qualities of the flexure. Increasing the length of the bending segments also makes the flexure less stiff in the other axes of motion. Increasing the overall length of the flexure increases the mass of the rigid section of the flexure between the two short bending segments. The rigid section between the two bending segments forms a spring-mass system which has resonances. Resonances are undesirable, but higher resonant frequencies are preferable to low resonant frequencies.
The ways that flexures are usually formed can easily lead to a resonant frequency that is low enough to be a real problem or performance limitation in a motion system. Currently, there are two primary methods of creating a flexure. One method, an additive process, shown in FIG. 1A , is to start with a relatively thin strip of flexible material 1 and add rigid strips 2 and 3 in the central section leaving thin bending segments 4 and 5 near each end 6 and 7 . Another method, a subtractive process, shown in FIG. 1B , is to start with a relatively thick bar 8 of material and machine notches or slots 9 and 10 near each of the two ends 11 and 12 to form the bending segments with the relatively rigid original bar in between. There are advantages and disadvantages to both approaches. The subtractive process is relatively more expensive, can make a stiffer flexure, and has no joints. The additive process can be less expensive, the bending elements and the central stiffener can be made of different materials, but it has mechanical joints bonding the parts, which can create additional vibration problems. In both cases, the central stiffener is typically solid which makes it stiff but it is also typically massive so that it has a relatively low specific stiffness (i.e., stiffness to mass ratio), which produces a low self-resonant frequency. FIG. 1C shows a flexure which has a center stiffened section created by bending sides 52 and 53 up 90 degrees, forming a “U” channel, leaving segments 50 and 51 to flex. This design does have a higher specific stiffness than a solid bar, but if the sides are made tall to maximize stiffness the sides become cantilevered masses with an additional low self-resonant frequency of their own. With typical flexure design and fabrication practices it is difficult to create a flexure that is compliant enough to act as a flexure and has a high self-resonant frequency.
It generally takes a system of flexure elements to create a functional unit that allows for motion primarily in one axis and is stiff in the other axes. Two such systems are shown in FIG. 2A and FIG. 2B . The system in FIG. 2A allows bodies 15 , 16 to move laterally with respect to each other, shown by the arrows. The flexure elements 13 , 14 constrain the motion so that the bodies remain parallel. The system in FIG. 2B couples a rigid core 20 with a rigid outer ring 21 with three flexure elements 17 , 18 , and 19 . This system constrains bodies 20 , 21 to move concentrically with respect to each other (i.e., in and out of the page). In each case, the flexure elements are formed as described above and shown in FIG. 1A and FIG. 1B . In such systems, each flexure element has resonances due to its shape and material properties (the same if the flexures are the same), and the system has complicated resonances.
What is needed is a flexure with a high stiffness. Furthermore, what is needed is a method for constructing a high stiffness flexure and/or flexure system that is composed of flexure elements with high self-resonant frequencies assembled in a way that minimizes the additional problems of a system. The present invention solves these and other problems by providing high stiffness flexure and method of making a high stiffness flexure as describe below.
SUMMARY
The present invention relates to the design and fabrication of flexures used to guide motion in mechanical systems. A high specific stiffness flexure includes two flexing sections separated-by a longer stiffened frame section. The present invention provides designs and processes for making flexures and flexure systems with monolithic high specific stiffness frame or box structures for the stiffened sections that creates relatively higher self-resonant frequencies. The present invention allows for creating short, thin, flexible segments of a high strength material, and creating the longer central frame section of the flexure with a high specific stiffness from a stiff material formed into a light weight but high stiffness geometry, so that the resonant frequencies are all high.
The following detailed description and accompanying drawings provide a better understanding of the nature and advantages of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-C show examples of prior art flexures.
FIGS. 2A-B shows two typical prior art architectures of flexure systems.
FIG. 3A is an isometric view of an example flexure according to one embodiment of the present invention.
FIG. 3B is a side view of the flexure in FIG. 3A .
FIG. 3C is a cross section of the flexure in FIG. 3A .
FIGS. 4A-C illustrate an example process of making a high stiffness flexure according to one embodiment of the present invention.
FIG. 5 is a flexure according to another embodiment of the present invention.
FIG. 6 is an example of a system using a flexure according to one embodiment of the present invention.
FIG. 7 is another example of a system using a flexure according to one embodiment of the present invention.
FIG. 8 illustrates an example of a flexure system and a process of making a high stiffness flexure according to one embodiment of the present invention.
FIGS. 9A-B illustrates another method of forming a flexure according to one embodiment of the present invention.
DETAILED DESCRIPTION
Described herein are techniques for improving flexures and systems that use flexures. In the following description, for purposes of explanation, numerous examples and specific details are set forth in order to provide a thorough understanding of different aspects of the present invention. It will be evident, however, to one skilled in the art that the present invention as defined by the claims may include some or all of the features in these examples alone or in combination with other features described below, and may further include obvious modifications and equivalents of the features and concepts described herein.
FIG. 3A is an isometric view of an example flexure according to one embodiment of the present invention. Flexure 300 may be made from a spring material such as stainless steel or Beryllium Copper, for example, which may be plated with Tin. It is to be understood that other materials may also be used depending on the application. Exemplary spring materials typically have a high strength so the material can flex across a large angle without breaking or becoming permanently bent. Flexure 300 includes a central stiffened section 310 comprising a stiffening frame 311 . Flexure 300 further includes flat spring segments 324 and 325 (i.e., flexing segments). Stiffening frame 311 is a structure that maintains the shape and provides support to the central section 310 . Frame 311 may be an open or closed structure adjacent to the flexure base for stiffening the central stiffened section. For example, the cross section of the frame may be a triangle or other shape as described in more detail below. Holes 322 and 323 illustrate example means to mount the flexure between two bodies. However, other mounting configurations may be used. Flat spring segments 324 and 325 are provided between the end holes and the central stiffened section 310 , and provide the primary means of flexing.
FIG. 3B is a side view of the flexure in FIG. 3A . In one specific embodiment, screws 331 and 332 may be used to mount the flexure in a system to rigid bodies 333 and 334 . When the flexure is mounted, rigid bodies 333 and 334 may move up or down relative to one another, causing screw 331 to move up or down relative to screw 332 . Flexing will occur primarily across flexing regions 311 and 312 of the spring segments 324 and 325 , but central stiffened section 310 is designed to be substantially rigid. Flexure 300 may have a thickness t 1 , and flexing regions may flex across regions 311 and 312 having lengths “L 2 ” and “L 3 .” The length of the central stiffened section 310 is “L 1 .” The spring segments of flexure 300 may have lengths “L 4 A” and “LAB.”
FIG. 3C is a cross section of the flexure in FIG. 3A . In this example, central stiffened section 310 includes a flat base 320 and sidewalls 327 and 329 . Base 320 and sidewalls 327 and 329 form a enclosed frame (e.g., a box-type structure) with an interior region 330 . In one embodiment, the frame structure is triangular. However, it is to be understood that other shapes for the frame structure may be used, such as polygons or curves such as semicircles or other arcs. Additionally, a circular flexure may have a concentric circular stiffening frame. Base 320 may have a width W, and the sidewalls 327 and 329 of the triangular cross section may have length L 5 and L 6 .
FIGS. 4A-C illustrate an example method of forming a flexure according to one embodiment of the present invention. FIG. 4A shows an unfolded view of an individual flexure including flexing segments 424 , 425 and the mounting holes 422 , 423 . FIG. 4C illustrates a cross section of the integral flexure. As illustrated in FIG. 4C , sides 427 and 429 may be folded toward each other to meet at the apex 450 of triangular cross section stiffened section 426 . Lap joint portion 428 is included to provide an overlapping joint (i.e., a “lap joint”) with side 427 .
In one embodiment, the flexure pattern may be cut from a sheet of spring material using a die, laser or EDM. Alternatively, the flexure pattern may be chemically etched from a sheet of spring material. If the flexure pattern is formed from a single sheet of material, there may be no preferential bend lines, unless perforations are added. Thus, the flexure may be formed by a machine.
FIG. 4B illustrates a method of forming a flexure according to one embodiment of the present invention. As shown in FIG. 4B , bend lines are created along folding lines to facilitate folding of the flexure elements. For example, a chemical etching process can provide a partial depth etch along folding lines to produce weakened lines to facilitate folding. If the partial etch it sized properly, a small or moderate size flexure can be readily folded by hand, for example.
FIGS. 4A-C illustrate a flexure where the stiffened section is formed integral to the flexure from a single piece of material. This technique is preferable because it creates a monolithic flexure. Alternatively, a high specific stiffness frame structure could be formed separately and bonded to a flat flexure. While similar results would be achieved, superior stiffening elements could be used at the cost of an additional bond between the flat flexure and the stiffener.
The stiffened section of the flexure can take various forms. FIGS. 3-4 illustrate flexures with triangular cross sectional stiffened sections. Alternatively, an additional side can be added to the pattern that would form a four-sided box structure. The box structure can take the form of a polygon cross section like a triangle, rectangle or trapezoid, or it could be a smooth curve like an arc. A rectangular cross section body has a higher specific stiffness, and therefore a higher self-resonant frequency, than a similar height triangular cross section body. However, for a given base width and total perimeter length, the triangle has the highest specific stiffness. A triangular cross section provides a closed shape so that unsupported sides won't resonant. Triangular cross sections are also advantageous because they are self-supporting in that such a structure cannot be folded into a parallelogram then collapse.
Independent of how the flexure is fabricated and what material the flexure is made from, the stiffening frame structure should be a closed shape so that the stiffened section acts as a single stiff monolithic body. If the frame structure is created by folding, the edges that come together to close the shape should be bonded together. A lap joint may be used as shown in FIG. 4C , and bonded by welding, brazing or soldering. A overlapping tape could be also be used, such as an adhesive tape with a strong substrate, for example.
A partial chemical etching process may produce weakened corners where the material was made thin to aid bending. This problem can be solved or reduced a couple of ways. One way is to leave the material its full thickness at the corners of the stiffened section adjacent to the flexing segments where the peeling stresses are concentrated. Another way, not mutually exclusive, is by filling, or partially filling, the stiffened section with a material for increasing the strength of the frame. For example, a low density substance like epoxy or rubber may be used to stabilize the structure without adding much mass. This filler material could also have damping qualities to help damp any resonance that gets excited. Alternatively, for damping, a damping material could be added to outside surfaces of the flexure.
If Tin plated Beryllium Copper alloy is used for the base spring material, a soldered lapjoint may be used to close the body on the stiffened section as shown in FIG. 4C . Solder can also be used in the inside corners as buttresses like the addition of epoxy as a filler mentioned previously. If steel is used for the base spring material, spot welding may be used. Beryllium Copper alloy is also non-magnetic unlike steel. Since steel is magnetic, it may interact with magnetic fields in the system, such as in a motor, for example.
FIG. 5 is a flexure according to another embodiment of the present invention. As illustrated in FIG. 5 , the specific stiffness of the central stiffened section can be further increased by providing lightening holes in the sides and or the base. This decreases the stiffness but can significantly increase the stiffness to weight ratio, which increases the self-resonance frequency. FIG. 5 shows an isometric view of an individual flexure with lightening holes 530 in the side.
Flexures according to embodiments of the present invention may be incorporated into improved flexure systems. FIG. 6 is an example of a system using a flexure according to one embodiment of the present invention. Flexure system 600 includes bodies 636 and 637 that move laterally with respect to each other, shown by the arrows. Flexure elements 601 and 602 constrain the motion so that the bodies remain parallel. Flexure elements 601 and 602 are comprised of flexing segments 631 and 632 and central stiffened section 633 . Flexure element 601 is attached to bodies 636 and 637 by screws 634 and 635 . Flexure element 602 may be attached to bodies 636 and 637 in the same way.
FIG. 7 is another example of a system using a flexure according to one embodiment of the present invention. The system in FIG. 7 includes a rigid core 738 coupled to a rigid outer ring 739 using three flexure elements 742 , 752 and 762 . Each flexure element comprises flexing segments 740 and 741 and a central stiffened section located between 740 and 741 . This system constrains bodies 738 and 739 to move concentrically with respect to each other (i.e., in and out of the page). The rigid core 738 could also be monolithic with the three flexure elements (i.e., a single piece of material), and the flexure elements may take the form of frames or box structures to achieve high stiffness and low mass as described above. Rigid outer ring 739 may he similarly constructed monolithic with the flexure elements.
FIG. 8 illustrates an example of a flexure system 800 and process of forming a flexure according to one embodiment of the present invention. A flexure system may include a rigid central core 830 coupled to a plurality of flexures 801 , 802 and 803 . In the present example, the core 830 is an advantageous triangular shape and three flexures 801 , 802 and 803 are positioned in parallel with each side of the core. The core may be attached to a first body at the inner flexure segments (e.g., using holes 831 , 832 and 833 or holes 834 , 835 and 836 ), and the outer segments of each flexure may be attached to a second body (i.e., using holes 851 , 852 and 853 ) so that the first and second bodies may move laterally (in and out of the page in FIG. 8 ) with respect to each other. Additional holes 837 - 838 may optionally be positioned around the core for attaching other elements of the first body or other bodies to the core. In one embodiment, the core includes an opening 890 . The opening may be centered in the triangle to achieve a balanced center of gravity, for example. In one embodiment, both the core 830 and the central opening 890 are triangular (e.g., an equilateral triangle), and the sides of the central opening 891 - 893 are parallel with the sides of the core 851 - 853 and the flexure elements 801 - 803 , respectively. Additionally, each apex of the triangular central opening may be flattened (i.e., each apex of the triangular central opening consists of a flat edge such as edges 854 , 855 and 856 ) to increase the rigidity of the core.
FIG. 8 also illustrates another aspect of the present invention. In one embodiment, individual flexures, or in this example the whole flexure system 800 , may be produced from a single sheet of spring material and then formed into a final product, wherein the core, flexures and stiffening frames comprise a single piece of material. For example, in one embodiment a single sheet of spring material is chemically etched or cut into the desired pattern (e.g., a triangle or other shape of the desired core and flexure(s)). The pattern may include stiffening sections 821 - 826 and lap joint sections 841 - 843 , which may be patterned and folded to form triangular frames for stiffening a central section of each flexure across a length L 1 . The stiffening sections 821 - 826 may be bonded to lap joint sections 841 - 843 along the entire length L 1 to form tightly coupled frame units on each flexure with relatively few and relatively high self-resonant frequencies.
In another embodiment, the core 830 may include stiffening frames as well. For example, a single piece of material may include core stiffening sections 861 - 866 , which may be folded to form triangular stiffening frames across the sides 891 - 893 of opening 890 and the parallel sides 851 - 853 of core 830 after the system has been patterned (e.g., by stamp cutting or etching). In this case, lap joint sections 841 - 843 may be divided into three sections as illustrated by lapjoint sections 841 A, 841 B and 841 C, with the end sections (e.g., lap joint sections 841 A and 841 C) forming lap joints with the stiffening sections (e.g., stiffening section 861 ) and the middle lap joint sections (e.g., lap joint section 841 B) forming lap joints with the core stiffening sections 861 - 866 . Similarly, the region between the flexure core and the inner flexure segments may also include stiffening frames illustrated by sections 897 A, 898 A and 899 A. Sections 897 A, 898 A and 899 A may be included at each corner of the triangle, for example, and folded to stiffen the corner from flexing.
FIGS. 9A-B illustrates another method of forming a flexure according to one embodiment of the present invention. FIG. 9A illustrates a force F exerted when the flexure is bending. In this case, a downward force is exerted that may tend to cause the stiffening frame 910 to separate from the base of the flexure 911 at the corner (i.e., a peeling stress). FIG. 9B illustrates a solution to this potential problem. In FIG. 9B , bend lines 901 and 902 are set back a distance “d” from the corners. Thus, if the bend lines are formed by a partial etch as described above, or by some other method that tends to weaken the material, the corners of the stiffening frame will be unaffected. Consequently, the flexure will be more resistant to tearing at the corners. In one embodiment, a mask may be used to etch the bend lines, wherein the mask window is set back from the corner created at the intersection of the flexing segment 924 and the frame sides 927 and 928 .
The above description illustrates various embodiments of the present invention along with examples of how aspects of the present invention may be implemented. Furthermore, embodiments of the present invention may be used in many different applications. For example, one of the many possible applications for the present invention is as guidance for a voice coil actuator used as either a positioning stage or a reciprocating pump.
Thus, the above examples and embodiments should not be deemed to be the only embodiments, and are presented to illustrate the flexibility and advantages of the present invention as defined by the following claims. For example the flexure pattern could be cut from a relatively thick sheet material and then the short flexing segments formed by etching the material thinner in those spots. Any necessary bonding could be done by welding or gluing. Other means of attaching to the flexure could be used. Dowel pins or sets of two screws, instead of single screws, could be used to attach the flexure to a body to prevent rotation about a single screw, for example. Based on the above disclosure and the following claims, other arrangements, embodiments, implementations and equivalents will be evident to those skilled in the art and may be employed without departing from the spirit and scope of the invention as defined by the claims.
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The present invention relates to the design and fabrication of flexures used to guide motion in mechanical systems. A high specific stiffness flexure includes two narrow and thin flexing sections separated by a longer stiffened section. The present invention provides designs and processes for making flexures and flexure systems with monolithic high specific stiffness frame or box structures for the stiffened sections that creates relatively higher self-resonant frequencies.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for communicating between nodes in a communications network, particularly, but not exclusively, an asynchronous transfer mode network for communicating delay sensitive low rate isochronous services such as voice data.
2. Related Art
In asynchronous transfer mode (ATM) networks a node on the network transmits data to another node in the network by loading the data into a cell which travels through the network. Taking, for example, a single telephone source or a number of telephone sources, the data will comprise regularly taken samples of the analogue voice information which is digitised. Once a buffer in the node has sufficient information to fill the cell the data block is transmitted to the other node. Subsequently further cells are filled in a similar manner and transmitted to the other node.
It will be appreciated that the voice information from one telephone conversation may be split up into samples which are transmitted in different cells and time delays which are perceivable by a telephone user can occur because of the need for each node to "gather" or receive enough information to fill a cell. The time delays manifest themselves as echoing, and although echo cancelling equipment is available which can alleviate this problem, such equipment is expensive and not always reliable. This has led to the belief that ATM is not a suitable technology to serve voice traffic or other delay sensitive low rate isochronous services.
The present invention arose from a realisation by the inventor that the currently perceived requirement to fill each cell with data does not need to be a rigid requirement. By only partially filling a cell with data, it would be possible to reduce the time delay introduced into the communications network by the buffering process used by each transmitting node. For example, it would be possible for a node to utilise one cell to transmit just one digitized sample from one telephone conversation. This would, of course, lead to an excessive load on the asynchronous transfer mode network because the other information that would have been carried by that cell would now have to be carried by other cells.
EP-A-0415843 discloses a data communication system for communicating data between nodes of the system. When a source node sends data to a destination node it splits the data into packets of, for example, 512 bytes each. In order to avoid congestion occurring in the system the maximum number of packets the source node can send at any given time, or the maximum rate at which it can send packets, is controlled in accordance with the round-trip delay between source and destination nodes. The maximum number or maximum rate is controlled to be higher for smaller delays and lower for larger delays.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a method of communicating data in blocks between first and second nodes in a communications network, the method comprising determining a time delay between transmission and reception of data blocks between the nodes and communicating the data in blocks the amount of data in each of which is controlled in accordance with the time delay thus determined, the amount of data in each block being controlled to be larger for smaller delays and smaller for larger delays, characterised in that the blocks are communicated within respective data cells which all have the same data-carrying capacity so that the fill factor of each cell is higher for smaller delays and lower for larger delays.
By determining the time delay between transmission and reception of data blocks between nodes and controlling the amount of data in each of the data blocks in accordance with the determined time delay it is possible to compromise between the load on the network and the time delay introduced by the node assembling the data into a data block prior to transmission.
For example, where the network has a low transmission path delay it may by tolerable to use a node's full buffer capacity to ensure that the amount of data in each data block is the maximum that can be contained in a cell before the data block is transmitted. If the transmission path has a relatively large time delay, in order to improve the quality of service by reducing performance factors like echo, it will be possible to reduce the amount of data in each data block so allowing the data block to be transmitted without having to wait for the buffer to fill to full capacity.
By data block is meant a discrete block or collection of data rather than a continuous data stream.
Preferably, the fill factor of the cells is determined by referring the determined time delay to a look-up table of appropriate cell fill factors corresponding to respective members of a set of time delays.
In some networks, the time delay may comprise a delay induced by a transmission path from the first node to the second node alone or this delay doubled to take into account the return path. Preferably, the time delay is determined for a communication path comprising a path from the first node to the second node and a path from the second node to the first node. Thus, the outgoing and return path of the network is considered. The path may be direct between the nodes or via other network nodes. The path could be the same for both directions or different. For example, the return path could involve more nodes in the network than the outward path or vice versa.
Preferably, the communications network operates in asynchronous transfer mode.
Preferably, each cell contains information indicating the amount of data contained in that cell. This may be such as to make it possible for the receiving node to determine the last item of data in the cell and to differentiate between that last piece of data and that part of the cell which is empty. Alternatively, the cell could include information indicating the location of the data within that cell. Thus, the cell may be organised time wise such that information within the leading portion of the cell points to the location of the data within the rest of the cell. The advantage of this will be appreciated when consideration is given to the processing of a received cell which is not a "full" cell. In such a cell there will be a part which contains useful data and a part which is "empty" in the sense that it does not contain useful data (although it could contain "dummy" non-useful data present just to fill the cell). It will thus save processing time if the "empty" part can be discarded and the useful data processed without delay.
According to a second aspect of the invention there is provided a communications network including first and second nodes, first means for communicating data in blocks between the nodes, second means for determining a time delay between transmission and reception of data blocks between the nodes, and third means for controlling the amount of data in each block to be larger for smaller delays and smaller for larger delays, characterised in that the first means is arranged to communicate the blocks in respective data cells which all have the same data-carrying capacity so that the fill factor of each cell will be controlled by the third means to be higher for smaller delays and lower for larger delays.
BRIEF DESCRIPTION OF THE DRAWINGS
A specific embodiment of the invention will now be described, by way of example only, with reference to and as illustrated by the drawings in which:
FIG. 1 shows a communications network comprising a number of nodes and transmission path links in schematic form;
FIG. 2 shows in schematic block diagram form a node of the network shown in FIG. 1; and
FIGS. 3 to 5 show in schematic form data blocks transmitted by nodes on the network shown in FIG. 1.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
FIG. 1 shows a communications network 1 comprising network nodes A, B, C and D linked together by transmission paths 2, 3, 4 and 5. Nodes A and B are linked together by transmission path 2; node B is linked by transmission path 3 to node C; node C is linked by transmission path 4 to node D; node D is linked by transmission path 5 to node A. The transmission paths are formed from optical fibre in a manner well known to a man skilled in the art of communications. The communications network 1 operates in Asynchronous Transfer Mode (ATM).
The nodes A, B, C and D are all nominally identical. As is shown in FIG. 2, each node comprises a node manager 6 linked by a data bus 7 of known type to a buffer 8. The buffer 8 has a data input 9 and output 10. The data input 9 is connected to a telephone network 100 served by node A in a known manner and permits voice data to enter the buffer 8 from the telephones in that network after a data mapping operation by an application layer such as AAL-1. AAL-1 is a process well known to those versed in the art of communications. Data output 10 provides a transmission path for the data to be transmitted as a data block from the node onto one of the transmission paths to which the node has access. The data block is transmitted by means of a transmitter receiver unit 22. The node manager 6 is also connected to a lookup table 11 by means of a data bus 12 and by a data bus 13 to a transmission path time delay determining means 14. The time delay determining means 14 has an input 15 and output 16 connected to the transmitter receiver unit 22 and a further databus connected to a node clock 23.
The lookup table 11 comprises a data store containing a set of time delays and associated appropriate cell filling factors.
Let us suppose that node A wishes to communicate with node B. From FIG. 1, it will be readily appreciated that the communication can take place by a direct path 2, direct in the sense that it has few intervening nodes and a short transmission path, or by a longer path comprising paths 4, 3, 5, node C and node D.
The first stage in the communication process is for node A to determine the time delay introduced by the chosen transmission path. The node manager 6 instructs the time delay determining means 14 to send a test data block in an ATM cell from node A to node B from the transmitter and receiver unit 22. This cell contains data representative of the time of its transmission from node A by the transmitter and receiver unit 22 which is written into the cell by the time delay determining means 14 after reference to a local clock 23. When this cell is received by node B it is immediately returned to node A. The time delay determining means 14 notes the time of receipt of this cell with reference to the clock 23 and determines the time delay of the transmission path between node A and node B by finding the difference between the noted time of receipt and the time of transmission which is recorded in the data carried by the cell.
The determined time delay is then passed back to the node manager 6 which compares it with various time delays stored in the look-up table 11 in order to select a suitable cell filling factor. The buffer 8 is then controlled by the node manager 6 in accordance with the factor to assemble or load voice data received from the network 100 into the next ATM time division or cell in the following manner.
Voice data derived from one of the telephones served by the node A is mapped by an adaptation layer, for example AAL-1, in a manner well known to those skilled in the art into a form suitable for loading into a segmentation and reassembly protocol data unit (SAR-PDU). The SAR-PDU in a typical network will be 48 octets in length, with 47 octets usable by data. The SAR-PDU travels through the network in the cell. The loading process is carried out by the buffer 8 under the control of the node manager 6.
The SAR-PDU is shown in FIG. 3 and it can be seen that it comprises a unit header 17, a fill level indicator field 18, and a user data field 19, a portion 19A of which is unused. The fill level indicator field 18 and the user data field 19 may occupy up to 47 octets and can be thought of as the payload of the SAR-PDU. The header 17 is one octet in length and the 48 octet SAR-PDU is preceded in the ATM cell by a cell header 20. The fill level indicator field 18 contains a fill level indicator which is derived by the node manager 6 from the fill level factor obtained from the lookup table and passed to the buffer 8 for loading into the SAR-PDU. Typically this will be 1 to 46 decimal or 000000001 to 00101110 binary.
The purpose of the fill level indicator is to indicate how much or rather how many octets of data are included in the SAR-PDU. Thus, the end of the user data 19 and the beginning the unused portion 19a can be readily determined by the receiving node, node B which can then verify that it has received all the data and that the SAR-PDU has not been corrupted during transmission.
FIG. 3 shows the type of SAR-PDU that would be transmitted from node A if there was a relatively large time delay in the transmission path to node B. This could be the case when the transmission path includes nodes D and C.
If a lower time delay path is chosen for the communications circuit between node A and node B, for example, if path 2 is chosen, then a longer buffer generated time delay is acceptable and more voice data may be packed into the SAR-PDU. The fill level indicator is recorded as a larger number reflecting an expansion of the user data area and a corresponding contraction of the unused portion 19A. Such a situation is illustrated in FIG. 4.
In an alternative embodiment of the invention, the SAR-PDU is configured in a slightly different way. As is shown in FIG. 5, where like reference numerals are used to signify like fields of the SAR-PDU generated in the earlier described embodiment, the unit has a header 17 a portion of user data 19 and an unused data storage area 19A. However, it will be seen that the user data is located towards the tail of the SAR-PDU with the unused data portion in front of it. Instead of a fill level indicator field 18 there is a pointer field 21 within which is stored a pointer to the location of the start of the user data 19. Again this is generated by the node manager 6 from the cell fill factor and loaded by the buffer 8. The user data area 19 can expand and contract to cater for different transmission path time delays in a similar manner to the earlier described embodiment. The pointer byte requires a value from 0 to 45 decimal that is 0000 0000 to 0010 1101 binary.
When the SAR-PDU is received by the node B, the cell fill indicator or the pointer will be used by that node to determine the amount of data it transmits in each data block in each ATM cell back to node A. Alternatively, node B could derive the appropriate cell filling factor in the same way as node A described above or it could be read from an initial connection set up data block, that is to say, a block not containing data concerned with user traffic but set up data, such as an appropriate cell filling factor derived by node A. This could be sent to node B prior to transmission of a block containing the data concerned with user traffic.
In alternative embodiments, the lookup table may be updated by a network manager in order to modify the network performance in the light of the network's current efficiency.
In some networks, where there is a danger of data corruption, a number of test cells may be sent to determine the transmission path time delay and the average or majority time delay used.
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A method and apparatus for communicating over a communications network includes determining a time delay between transmission and reception of data block between nodes in the network and controlling the amount of data transmitted in the data blocks according to the determined time delay, the time delay produced by assembling the data blocks is modified thereby controlling the overall system time delay which includes a transmission path delay and a delay caused by the assembly of the data block by the network nodes.
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TECHNICAL FIELD
[0001] The present invention relates to hybrid composite silicon/organic field effect devices wherein the gate charge is induced by electrical as well as environmental elements.
BACKGROUND INFORMATION
[0002] The use of gas sensors and sensor arrays for odor analysis has attracted a great deal of attention in recent years. The principal goal of such research is to create a technology that can detect a wide range of odors with sufficient reproducibility, selectively, and stability to enable the construction of electronic noses that possess learning, storage, and recognition capabilities. Such systems are expected to be useful in a number of applications including food processing, environmental remediation, agriculture, and medical diagnostics. Organic transistors are being investigated for use in low cost flexible circuitry and in displays. It has been shown that organic transistors also make excellent gas sensors. The sensitivity of some organic transistors and a few gases has been noted in previous work. It is been shown that more information is available from a transistor sensor than an equivalent to chemiresistor sensor. It is an shown that field effect devices with active layers comprised of thin film of a conjugated small molecule, oligomer, or polymer, possess many of the required characteristics of gas sensors. It is been demonstrated that such devices are sensitive to a wide range of vapors at concentrations in the ppm range. The large variety of semiconductor materials available and the degrees of freedom available in modifying their molecular and morphological structures enable the construction of sensor arrays that could detect odors through pattern recognition.
[0003] The basic structure of the field effect sensor shown in FIG. 1 (a) of “Electronic Sensing of Vapors with Organic Sensors” Applied Physics Letters, Volume 78, Number 15, Apr. 9, 2001. The field effect sensor consists of a thin film (of the order 10-100 nm) of an active semiconductor deposited by either a vacuum sublimation or solution-based techniques on dielectric-coated conductor. Gold electrodes are evaporated over the semiconductor with spacing of 200 um. The devices is biased so that the channel has a field-induced charge with densities in the range of 10 12 -10 13 cm −2 . The functioning of such field effect devices is described in the literature. Measurements were also made with zero gate bias. The morphology of semiconductor materials used in the study is polycrystalline with grain size in the 10-100 nm range.
[0004] While the organic transistors demonstrate a change in drain to source current when its semiconductor channel is exposed to selected gases, their sensitivity is low and it is difficult to “reset” the device by clearing out the trapped charges after an exposure to an analyte gas. Additionally, in previous work on organic FET sensors, the active organic transistor channel has a dual role: sensing as well as transduction. This dual role may cause reliability problems. Therefore there is a need for a new gas sensor device that uses a organic field effect transistor (FET) device combined with a silicon semiconductor field effect device that is more sensitive and has the ability to be electronically reset. There is also a need for a gas sensor device where the sensing takes place in the organic FET and transduction takes place in a parallel integrated silicon FET device.
SUMMARY OF THE INVENTION
[0005] A new four-terminal FET chemical sensor device is described that consists of two coupled channels: one comprising an organic or polymeric semiconductor and the second comprising silicon. The gates while common are not electrically connected to any external potential. The four terminals consist of source and drain terminals electrically coupled to the channel of the organic semiconductor and source and drain terminals electrically coupled t to the channel of the silicon semiconductor.
[0006] In one embodiment, the silicon device is fabricated on to a P-type substrate by diffusion of N+ material to form the source and drain regions and N − material to form the channel region. An insulator layer (e.g., SiO 2 ) is deposited over the N-channel of the silicon semiconductor. Next, a suitable semiconductor organic material is deposited on the insulator layer forming the channel of the organic field effect device. Source and drain contacts are deposited at each end of organic semiconductor channel. The source and drain contacts for the organic semiconductor channel are of a material type for making good electrical connection to the organic semiconductor material.
[0007] The two channels are coupled such that charges induced in one channel will modify the conduction of the other channel due to the common gate insulator layer. In one embodiment, the organic channel is exposed to air such that it is able to interact with chemicals in the ambient environment. This interaction enables the new four terminal device to have multiple modes of operation, the common gate region may be charged from chemicals interacting with the exposed organic channel, the organic channel may be electrically reset by applying appropriate potentials to its source and drain, the silicon semiconductor channel may be charged electrically to modify the organic channel, etc. In all cases, the conduction of the channels may be measured by monitoring current in the respective organic and silicon semiconductor channels before and after exposure to either environmental or electrical stimulus.
[0008] This four terminal field effect device of the present invention represents a major improvement over both the traditional CHEMFET which is a silicon MOSFET with the gate uncovered to be chemically sensitive and an organic transistor chemical sensor. While the four terminal field effect device of the present invention may also function as a traditional CHEMFET, one of the more powerful sensing modes occurs when the two channels are coupled and changes in the organic channel carrier density in response to analyte delivery are reflected as changes in the current through the silicon channel.
[0009] The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] 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:
[0011] FIG. 1 is a cross-section view of a composite field effect device according to embodiments of the present invention;
[0012] FIGS. 2A-2D illustrates drain to source current resulting from various operations of the field effect device of the present invention;
[0013] FIGS. 3A-3B illustrates drain to source current resulting from various operations the field effect device of the present invention;
[0014] FIG. 4 illustrates charge distributions during and after analyte delivery to the field effect device of the present invention;
[0015] FIG. 5 a flow diagram of method steps used in another embodiment of the present invention; and
[0016] FIG. 6 is a block diagram of a sensor system suitable for practicing embodiments of the present invention.
DETAILED DESCRIPTION
[0017] In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. For example, specific details of certain semiconductor process steps. In other instances, well-known sub-systems have been shown in block diagram form in order not to obscure the present invention in unnecessary detail.
[0018] Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.
[0019] FIG. 1 is a cross-section view of a combination hybrid organic and silicon semiconductor FET device 100 according to embodiments of the present invention. The first step in device fabrication is to fabricate a silicon N-channel field effect transistor (NFET). Using photolithography and ion-implantation techniques, source 102 and drain 104 regions are patterned and doped with phosphorous in a P-type silicon substrate 101 (resistivity: 2-8 Ω-cm). The NFET is designed to be a depletion mode (normally on) device and the channel region 103 is doped with phosphorous realize a threshold voltage (VT) near zero volts. A thin (e.g., 40 nm thick) dielectric (e.g., SiO 2 ) forms the common gate region 113 and is thermally grown through a combination of wet and dry processes. Aluminum metal 108 and 109 electrodes are is sputtered on the source and drain regions 102 and 103 respectively of the NFET to form ohmic contacts. The source and drain electrodes are 102 and 103 then covered with a silver deposition 106 and 107 respectively using e-beam evaporation.
[0020] Organic semiconductor material is deposited over a portion of the common gate region 113 to form the channel 111 of an organic P-channel FET (PFET) device. The source and drain electrodes of the organic PFET device is then formed by depositing silver 110 and 112 . The surface of channel 111 is exposed to the ambient environment 114 . Source/drain electrodes 110 and 112 of the organic semiconductor PFET and 106 and 107 of the silicon semiconductor NFET may be electrically coupled to circuitry which enables different potentials to be applied for different modes of operation of the hybrid combination four terminal device 100 .
[0021] In forming the organic PFET, hexamethyldisilazane (HMDS), which is a self-assembled monolayer (SAM), is first deposited on the SiO 2 gate region 113 . Next, pentacene is deposited using vacuum deposition technique as the organic semiconductor channel 111 . The SAM is used to improve the crystalline ordering of the pentacene on the SiO 2 gate region 113 . If need be, an indium substrate contact (not shown) may be used to externally modify the threshold voltage through changing the bias on substrate 101 . In experimental devices, three different channel lengths of 35 μm, 54 μm and 1 mm have been used for the silicon semiconductor NFET while keeping the channel 103 width to length (W/L) ratio equal to 5.
[0022] The combination hybrid organic and silicon semiconductor FET device 100 in FIG. 1 has four terminals, the source and drain terminals of the organic semiconductor PFET and the source and drain of the silicon semiconductor NFET. By applying various bias voltages to these terminals, the operation modes device 100 may be electrically changed while the common gate allows the organic PFET to modify the silicon NFET when its organic semiconductor channel is exposed to analyte. Likewise, the silicon semiconductor channel may be charged electrically and modify the response of the organic semiconductor channel to an analyte. Two of the most common modes of operation for device 100 is the Chemical Field Effect Transistor (CHEMFET) mode and the Chemical Memory Mode.
[0023] In the Chemical Memory Mode, the NFET is biased such that it is ON and the PFET is OFF. In this first step, the current in silicon semiconductor channel 100 is then measured. Next, both the NFET and the PFET are biased such that they are both ON, wherein the common gate region causes cross-gating between the two devices. At this step, the analyte (e.g., ethanol vapor) is delivered to the organic semiconductor (pentacene) channel. The analyte causes changes in the free carrier density in the PFET due to the interaction between the analyte and the pentacene layer which leads to hole trapping. Essentially, the analyte molecules polarized and the resultant dipoles are held by electrostatic attraction to the holes in the organic semiconductor channel 111 . In the next step, the bias is removed such that the holes which are not trapped exit the organic semiconductor channel 111 while trapped holes remain and significantly alter current in silicon semiconductor channel 103 . The current in silicon semiconductor channel 103 has been shown to increase as much as 65 times in experimental models. This increase comes from the charged holes trapped in the pentacene layer which create an accumulation of electrons in addition to the residual charges in the doped silicon channel. This increase can be described as an increase in current due to a decrease in the threshold voltage of the silicon NFET. Since the channel current has a well know exponential dependence on the difference between the gate to source voltage and the threshold voltage in the sub-threshold region, maximum change in channel current is expected in this sub-threshold region of operation.
[0024] The trapped holes in the organic semiconductor channel 111 can be released by reverse biasing the device for an extended time (e.g., 60 seconds), enabling the sensor device 100 to be electrically refreshed. The ability to electrically refresh the sensor device 100 , according to embodiments of the present invention, is a major advantage over traditional CHEMFET sensors which often experience drift in their sensor characteristics with time due to inefficiencies in removing trapped charges/dipoles after a sensing event.
[0025] FIG. 2A illustrates the drain to source current through the silicon semiconductor channel 103 in the Chemical Memory Mode after the following steps. First, both the silicon NFET and the organic PFET are biased ON while the organic semiconductor channel 111 is exposed to an ethanol analyte. Secondly, the bias on the organic PFET is removed such that the holes which are not trapped exit the organic semiconductor channel 111 . The trapped holes remain in organic semiconductor channel 111 and induce charge carriers, via the common gate region, in the silicon semiconductor channel 103 significantly increasing its channel current. As shown the channel current in the silicon semiconductor channel 103 increases by a factor of 65 before relaxing to a value of 45 in approximately 30 seconds.
[0026] FIG. 2B illustrates the change in the silicon semiconductor channel 103 following the steps recited relative to FIG. 2A with the exception that the background environment is Nitrogen instead of air as was the case relative to FIG. 2A . In this case the silicon semiconductor channel current increased by a factor of 97 instead of 65 and the decay over time was less. The explanation for this is still under investigation.
[0027] FIG. 2C illustrates measurements taken in the CHEMFET mode wherein the NFET is biased ON and the PFET is biased OFF. In this case, the NFET channel current increases only about 2.5% during ethanol analyte delivery. This change may be accounted for realizing that the polar nature of the ethanol analyte weakly interacts with the organic semiconductor P-type channel and induces accumulation of electrons in the silicon semiconductor N-type channel.
[0028] FIG. 2D illustrates the silicon semiconductor drain/source current (I DS ) in the organic thin film transistor (TFT) based sensing mode. In this mode, the silicon NFET is biased such that its V Drain and V Sounce are equal to zero volts and the organic PFET is biased ON. Upon ethanol analyte delivery, a measurement of the organic semiconductor channel current reveals that the current appreciably decreases by a factor of approximately two to one.
[0029] For measuring the absolute sensitivity of the device in the chemical memory mode, a second measurement set-up was used. A probe station which can be pumped down to less than 10 −4 torr is connected with two high precision needle valves that can control the flow rate of any gas. Ethanol source is connected to one valve and the second valve is used to bleed in diluting gas (nitrogen or normal moist air) to further dilute the ethanol mixture. Gases are bled in at less than 10 −4 torr pressure to reach 450 torr and the partial pressures are chosen to reach at a desired ppm/ppb level of ethanol. Before any measurements, the device is left to equilibrate with the ambient. First, the effect of both nitrogen and air diluting gases, treating each as analytes themselves, was measured in the Chemical Memory Mode. Subsequently, measurements with ethanol and diluting gas mixture were conducted. The measurements in diluting gas were subtracted from those of the ethanol mixed with the diluting gas to calculate the actual ethanol response. It was found that when Nitrogen is used as a diluting gas, the Minimum Detection Limit (MDL) of ethanol is 50 ppb, curves 301 in FIG. 3A ). For statistical reliability, measurements in each kind of ambients were done for five times on the same device. These multiple measurements in ethanol mixed in Nitrogen and Nitrogen alone are plotted together as bands 303 and 304 respectively. It is evident in FIG. 3B that each measurement in the ethanol mix is widely separated from each measurement in Nitrogen. Although most of the literature available on sensitivity measurements describe measurements in controlled ambient such as nitrogen, dry air etc., it is important to know the effect of moisture present in air on the sensor performance. Thus, normal room air at 42% relative humidity is used as a diluting gas as well and the same measurements as described in above paragraph were repeated. The MDL of ethanol when mixed with air is 30 ppm. To further improve the MDL, receptors may be used to increase sensitivity.
[0030] FIG. 4 shows a pictorial sequence illustrating the theory of operation of the composite 4 terminal organic/silicon field effect device according to embodiments of the present invention. The operation was determined from analysis of the CM mode, CHEMFET mode, and the organic TFT based sensor mode. For simplicity the silicon semiconductor channel is not outlined. In frame (a), pentacene grains 401 of the organic semiconductor channel are shown deposited on the common SiO 2 gate region over the silicon semiconductor channel 403 . In frame (b), analyte is delivered to the organic semiconductor channel wherein the interaction between the analyte and the organic semiconductor channel is dependent on whether the PFET is biased ON or OFF. When the PFET is biased ON, holes in the P-channel are electrostatically coupled with the electrons 403 in the silicon semiconductor N-channel (not outlined). The dipoles present in the analyte bind some free holes in the organic semiconductor material 401 through columbic forces forming and exemplary bound hole 404 . This binding between holes and analyte dipoles reduces coupling between holes and electrons in both the silicon semiconductor and the organic semiconductor channels and some electrons (e.g., exemplary electron 406 leave the silicon semiconductor channel as shown in frame (c). As soon as the analyte delivery ends, analyte molecules evaporate to the ambient because of weak coupling between polar analyte (alcohol) and non-polar organic layer (pentacene) leaving most of the holes in the deep traps. These trapped holes 407 again induce electrons (e.g., exemplary electron 406 ) into silicon semiconductor channel. These trapped holes, which were not present during the silicon channel current measurement before analyte delivery, induce additional electrons in the channel and increase the current after analyte delivery during the CM mode.
[0031] In the CHEMFET mode, the PFET is biased OFF upon analyte delivery. In this case, the dipoles have a weak interaction with the organic semiconductor which momentarily attracts them to the surface where they align themselves at the dielectric-organic interface such that their positive pole is coupled with the residual electrons in the N-channel and produces an increase in current as shown previously in FIG. 2C . When analyte delivery ends in the CHEMFET mode, the concentration of dipoles gets reduced as the analyte molecules leave the device surface and the silicon channel current returns to its initial charge distribution state.
[0032] Comparisons across different sensor platforms may be difficult owing to different test procedures used. However, it may be stated that the 4 terminal composite field effect device fabricated according to embodiments of the present invention and operated in the CM mode is 10-100 times more sensitive than an a traditional CHEMFET device. This difference in sensitivity results because in the traditional CHEMFET, it is dipoles attached to the gate that cause a charge perturbation in the FET channel whereas in the 4 terminal composite field effect device according to embodiments of the present invention, it is the unipolar charges that are trapped, as in a memory, that cause channel conductivity modulation. The modulation remains in effect until the trapped charges are released by an applied reverse bias.
[0033] FIG. 6 illustrates a sensor system 600 suitable for practicing embodiments of the present invention. A four terminal composite field effect device 605 is made according to embodiments of the present invention and may be operated in one of multiple modes. For example it may be operated in the CM mode whose steps are outlined in FIG. 5 . Four terminal composite field effect device 605 may be housed in a sensor head 604 with an opening 611 . Dotted line 612 illustrates a closure that may be used to seal device 605 from the environment during reset. The four terminals are wired ( 606 ) to control unit 601 , where terminals 1 and 3 are coupled to the drain and source of the organic semiconductor device and terminals 2 and 4 coupled to the drain and source of the silicon semiconductor device. Terminals 1 and 2 are wired through exemplary current sensing resistors analog to digital (A/D) and digital to analog (D/A) circuits 603 . Other devices may be used to sense channel current in the field effect devices and still be within the scope of the present invention. Processor 602 stores data and instructions in memory 609 . The instructions may be preloaded and contain the steps necessary to implement the various modes of operation for composite field effect device 605 according to embodiments of the present invention. The processor sends data to A/D and D/A unit 603 which is converted to voltage potentials necessary to bias composite field effect device 605 for various operation modes or to reset it after a measurement is made. Power system 608 provides the power supply voltages for the processor 602 , memory 609 , and A/D and D/A unit 603 . Environmental gases 610 are sampled when closure 612 is opened exposing the organic semiconductor channel to the environment.
[0034] Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
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A four terminal field effect device comprises a silicon field effect device with a silicon N-type semiconductor channel and an N+ source and drain region. An insulator is deposited over the N-type semiconductor channel. An organic semiconductor material is deposited over the insulator gate forming a organic semiconductor channel and is exposed to the ambient environment. Drain and source electrodes are deposited and electrically couple to respective ends of the organic semiconductor channel. The two independent source electrodes and the two independent drain electrodes form the four terminals of the new field effect device. The organic semiconductor channel may be charged and discharged electrically and have its charge modified in response to chemicals in the ambient environment. The conductivity of silicon semiconductor channel is modulated by induced charges in the common gate in response to charges in the organic semiconductor channel.
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RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. §119 to U.S. Provisional Patent Application Ser. No. 61/577,028, filed Dec. 18, 2011, and entitled “The Klein solar thermal receiver”; which is incorporated herein by reference in its entirety for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a system using concentrated radiation as the mode of heating a fluid situated inside the vessel, and more particularly solar energy systems with solar receivers.
BACKGROUND OF THE INVENTION
[0003] The following publications, the disclosures of which are hereby incorporated by reference, are believed to represent the current state of the art:
[0004] U.S. Pat. Nos. 5,931,158; 5,947,114; 6,516,792 B2,
Kribus, A., Zaibel, R., Carey, D. Segal, A., Karni, J. 1998, “A solar-driven combined cycle power plant”, Solar Energy 62(2):121-129. Mills, D., 2004, “Advances in solar thermal electricity technology”, Solar Energy 76:19-31. Woerner, A., and Tamme, R., 1998, “CO 2 reforming of methane in a solar driven volumetric receiver-reactor” Catalysis Today 46:165-174. Berman, A., Karn, R. K., Epstein, M., 2005, “Kinetics of steam reforming of methane on Ru/Al 2 0 3 catalysts promoted with Mn oxides”. Applied catalysis A: General 282:73-83. Gordon, J. M. and Ries, H, 1993 “Tailored edge-ray concentrators as ideal second stages for Fresnel reflectors”, Applied Optics 32(13):2243-2250
[0010] The invention relates to radiation based energy systems, such as systems using concentrated solar radiation to produce heat, electricity or to drive chemical reactions. The concentrated solar radiation can be used to directly or indirectly, drive turbines for electricity production. Central to the energy system is the vessel converting the radiation to sensible heat. This vessel is often called a solar receiver.
[0011] The invention relates to a kind of solar receiver commonly called a volumetric receiver. In this type of vessel, the working fluid entering the receiver, for the purpose of heating and possibly also for chemical conversion of the fluid, is directly exposed to concentrated solar radiation by allowing the radiation to enter the vessel through a window. The window prevents the working fluid from mixing with ambient air, and prevents loss of pressure and/or the loss of already acquired heat in the incoming fluid.
[0012] One of the most challenging aspects of this type of vessel is maintaining the integrity of the window. Pressure stresses, thermal stresses and issues of differences of thermal expansion between the window and other material in direct contact with the window can cause the window to crack, break or shatter. It is an object of the present invention to provide a positioning and sealing mechanism for the window that will put the least stress on the window and a design for a radiation absorber that will contribute to the lowering of thermal stresses on the window.
[0013] Another challenging aspect of this type of receiver is the integrity of the radiation absorber. Pressure stresses and thermal stresses and issues of differences of thermal expansion between the absorber and other material in direct contact with the absorber can cause the absorber to melt, crack, break, crumble or shatter. It is an object of the present invention to provide a solution for, this problem by applying different materials with different radiation absorbing properties in different parts of the absorber.
SUMMARY OF THE INVENTION
[0014] The present invention seeks to provide improved vessels for heating a fluid with concentrated, radiation, preferably solar radiation.
[0015] There is thus provided in accordance with a preferred embodiment of the present invention a vessel for heating a fluid with concentrated radiation, which includes: a housing with an aperture and an ingress and an egress for fluid; a window covering the aperture in said housing for admitting and passing into the vessel concentrated radiation; a flow guide separating the fluid from the ingress from the fluid from the egress; and a permeable radiation absorber.
[0016] Preferably, the window is flat.
[0017] Most preferably the window covering the aperture is concave with the center of the window being deeper inside the body of the radiation receiving vessel than the rim of said window. The concave shape preferably follows an axis symmetric shape such as the radius of a sphere, a parabola, cone, capped cone, a combination of the mentioned shapes and other concave possibilities.
[0018] Preferably, the window is placed on a seal to seal the aperture from fluid exchange with the ambient air.
[0019] Most preferably the window is kept in place on the seal in the absence of any mechanism other than weight, gravity and friction to keep it in place. No other material is in direct contact with the window than the seal.
[0020] Preferably, the window flange is actively cooled.
[0021] Preferably, the window is actively cooled.
[0022] Most preferably, the window is actively cooled from the outside.
[0023] Preferably, the radiation absorber has at least two different areas with different radiation absorptivity, accomplished by the use of different absorption materials or by applying different external coating on the radiation absorbing side of the radiation absorber.
[0024] There is also provided in accordance with a different preferred embodiment of the present invention a system for heating fluid with concentrated, radiation, preferably solar radiation. The system includes: concentrating devices to concentrate radiation from a radiation source; a vessel in which the concentrated radiation heats a fluid and a utilizer of the stored energy in the fluid.
[0025] Preferably, the fluid contains any, all or a subset of the compounds; oxygen, methane, hydrogen, carbon dioxide, carbon monoxide, nitrogen, H 2 O.
[0026] Most preferably, the fluid is air.
[0027] Preferably, the radiation is concentrated and directed to the radiation receiving vessel by a primary optical device such as; an optical lens, a heliostat field with mirrors directing solar radiation to a target or a parabolic mirror or any combination of these concepts.
[0028] Preferably, the radiation from the primary optical device is further concentrated by a secondary optical device located in close proximity in front of or around the aperture of the radiation receiving vessel such as; additional lens or lenses, a compound parabolic concentrator, a concentrator following closely or approximately the mathematical shape of a truncated cone, tailor-edge-ray concentrator and a trumpet flow-line concentrator.
[0029] Preferably, the secondary optical device is actively cooled by water or other liquid coolant.
[0030] Preferably, the radiation receiving vessel is configured as described in paragraph [0015] to [0023] in the present description, to heat a fluid by incoming concentrated radiation.
[0031] Preferably, the heated fluid is utilized to heat, directly or indirectly, all or part of the fluid to drive a turbine for electrical generation.
[0032] Most preferably, the heated fluid is used to heat all or part of the fluid, directly or indirectly, to drive a gas turbine for electrical generation.
[0033] Preferably, the heated fluid from the radiation receiving vessel, which does not have a sufficiently high temperature to, economically or practically, be applied to electricity generation can be used for heating purposes such as; heat pump, boiler, absorption chiller, hot water heater, space heater.
[0034] Most preferably, the fluid from the radiation absorbing vessel is first used to drive a turbine for electrical generation and afterwards used for heating purposes as described in [0033].
[0035] There is also provided in accordance with a different preferred embodiment of the present invention a system for heating fluid with concentrated, radiation, preferably solar radiation and to provide sufficient heat to also chemically alter the composition of the fluid. The system includes: concentrating devices to concentrate radiation from a radiation source and funnel the concentrated radiation to a reaction vessel; a reaction vessel receiving the concentrated radiation to heat and chemically alter a fluid and a utilizer of the stored heat and chemical compounds in the fluid.
[0036] Preferably, the incoming fluid to the reaction vessel contains any, all or a subset of the compounds; oxygen, methane, hydrogen, carbon dioxide, carbon monoxide, nitrogen, H 2 O.
[0037] Preferably, the outgoing fluid from the reaction vessel contains any, all or a subset of the compounds; oxygen, methane, hydrogen, carbon dioxide, carbon monoxide, nitrogen, H 2 O.
[0038] Preferably, the radiation is concentrated and directed to the radiation receiving vessel by a primary optical device such as; an optical lens, a heliostat field with mirrors directing solar radiation to a target or a parabolic mirror or any combination of these concepts.
[0039] Preferably, the radiation from the primary optical device is further concentrated by a secondary optical device located in close proximity in front of or around the aperture of the radiation receiving vessel such as; additional lens or lenses, compound parabolic concentrator, a concentrator following closely or approximately the mathematical shape of a truncated cone, tailor-edge-ray concentrator and a trumpet flow-line concentrator.
[0040] Preferably, the secondary optical device is actively cooled by water or other liquid coolant.
[0041] Preferably, a reaction vessel for heating and chemically altering a fluid with concentrated, radiation, preferably solar radiation, is used.
[0042] Preferably, this reaction vessel is a vessel, which includes; a housing with an ingress and an egress for fluid and an aperture, a window covering the aperture of the housing for admitting and passing into the vessel concentrated radiation, a flow guide separating the fluid from the ingress from the fluid from the egress, a permeable radiation absorber.
[0043] Preferably, the window in the reaction vessel described in [0042] is flat.
[0044] Most preferably the window covering the aperture of the reaction vessel described in [0042] is concave with the center of the window being deeper inside the body of the radiation receiving vessel than the rim of said window. The concave shape preferably follows an axis symmetric shape such as the radius of a sphere, a parabola, cone, capped cone, a combination of the mentioned shapes and other concave possibilities.
[0045] Preferably, the window is placed on a seal to seal the aperture the reaction vessel described in [0042] from fluid exchange with the ambient.
[0046] Most preferably the window of the reaction vessel described in [0042] is kept in place on the seal in the absence of any mechanism other than weight, gravity and friction to keep it in place.
[0047] Preferably, the window flange of the reaction vessel described in [0042] is actively cooled.
[0048] Preferably, the window of the reaction vessel described in [0042] is actively cooled.
[0049] Most preferably, the window of the reaction vessel described in [0042] is actively cooled from the outside.
[0050] Preferably, the radiation absorber of the reaction vessel described in [0042] is able to absorb the concentrated radiation and transfer the heat to the fluid.
[0051] Most preferably, the radiation absorber of the reaction vessel described in [0042] has at least two different areas with different radiation absorptivity, ascertained by the use of different absorption materials or by applying different external coating on the radiation absorbing side of the radiation absorber.
[0052] Preferably, the reaction vessel described in [0042] is equipped with a high surface area covered with catalyst material to enable chemical alterations of the fluid inside the vessel.
[0053] Most preferably, the high surface area provided with catalyst material is integrated with the radiation absorbing surface.
[0054] Preferably, the heated fluid exiting the reaction vessel described in [0042] is used to preheat the fluid entering the reaction vessel described in [0042].
[0055] Preferably, the fluid leaving the reaction vessel is used to perform chemical reactions such as; combustion of the fluid and conversion of the fluid to liquid fuel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:
[0057] FIG. 1 is a simplified partially block diagram, partially schematic illustration of a system for heating a fluid with concentrated radiation in a vessel, constructed and operative in accordance with a preferred embodiment of the present invention; and
[0058] FIG. 2 is an enlarged view of area A of the vessel shown in FIG. 1 .
[0059] FIG. 3 is a schematic view of the radiation absorbing surface, 127 , shown in FIG. 1 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0060] Reference is now made to FIG. 1 , which is a schematic illustration of a vessel for heating a fluid with concentrated solar radiation, constructed and operative in accordance with a preferred embodiment of the present invention.
[0061] As seen in FIG. 1 , the present invention provides a system 100 for heating a fluid with concentrated radiation including a fluid supply source 102 . Examples of fluids include: oxygen, nitrogen, carbon dioxide, carbon monoxide, hydrogen, gaseous hydrocarbons, steam or a combination of the above mentioned fluids.
[0062] A radiation receiving vessel 120 , such as a vessel described inter alia in the above-referenced US patents: U.S. Pat. No. 5,931,158, U.S. Pat. No. 5,947,114 and U.S. Pat. No. 6,516,792 B2, the disclosures of which are hereby incorporated by reference, receives the fluid from the fluid supply source 102 , preferably at a pressure of between 1-200 bar, and most preferably at a pressure of about 1.5-10 bars.
[0063] Preferably, radiation is highly concentrated prior to impinging on the radiation receiving vessel 120 .
[0064] Preferably, the highly concentrated radiation originates from the sun.
[0065] Preferably, concentration of the solar radiation is provided by directing incoming solar radiation through a concentrator 125 . Concentrator 125 may have various possible configurations such as those described inter alia in the above-referenced publications of Kribus, A., Zaibel, R., Carey, D. Segal, A., Karni, J. 1998, “A solar-driven combined cycle power plant”, Solar Energy 62(2):121-129, and Mills, D., 2004, “Advances in solar thermal electricity technology”, Solar Energy 76:19-31, the disclosures of which are hereby incorporated by reference. Heliostat fields and parabolic dished are the most preferred primary concentrators for concentrator 125 . The concentrator 125 can, but is not forced to, consist of both primary and secondary optics, example of which are described inter alia in the above-referenced publications of Gordon, J. M. and Ries, H, 1993 “Tailored edge-ray concentrators as ideal second stages for Fresnel reflectors”, Applied Optics 32(13):2243-2250, the disclosures of which are hereby incorporated by reference. Compound parabolic concentrators and cone shaped concentrators are most preferred as practical secondary optics devices for concentrator 125 . The output of concentrator 125 is directed through a window 126 of the radiation receiving vessel 120 so as to impinge onto a radiation absorbing surface 127 , located on the permeable heat transfer wall 128 . Window 126 is preferably formed of quartz and may be of any suitable shape such as flat or curved. Solar reactors having concave windows, described in the above-referenced U.S. patents: U.S. Pat. No. 5,931,158, and U.S. Pat. No. 6,516,794 may be suitable for this purpose. As used herein, in specifications or in claims, the term “concave” incorporates all shapes, where the center of the shape is deeper inside vessel 120 than the perimeter of the same shape.
[0066] Preferably, window 126 is placed on a seal 140 , as illustrated in FIG. 2 , window 126 is kept in place on seal 140 , placed on aperture opening surface 142 , solely by the force of gravity acting on the weight of the window 126 and the friction between window 126 , the seal 140 and the aperture opening surface 142 . Preferably, the window is only in direct contact with the seal and with no other device. If the vessel is operating under pressure the pressure inside the vessel assists in fixing the window in location and to seal the aperture 144 , by forcing the window 126 towards the aperture opening surface 142 . Thermal stresses and difference in thermal expansion between the window and its holding devices have been known in prior art to cause breakage to windows in similar vessels.
[0067] The permeable heat transfer wall 128 is preferably formed of silicon carbide, silicon nitrite, alumina, or metallic wire mesh or other metallic, high surface area configuration.
[0068] The permeable heat transfer wall 128 may employ any suitable catalyst on surface 127 if the objective of system 100 is not only to heat the fluid from the fluid supply source 102 , but also to react the fluid. For high temperature reactions the most preferred catalysts are Ruthenium and Rhodium. A somewhat less preferred catalyst is Iridium and even less preferred catalysts are Nickel, Platinum and Palladium. These catalysts are preferably applied over a pigmented wash coat which is deposited on highly porous support structures such as ceramic matrices, preferably formed of silicon carbide or alumina, as described inter alia in the above-referenced publications of Woerner, A., and Tamme, R., 1998, “CO 2 reforming of methane in a solar driven volumetric receiver-reactor” Catalysis Today 46:165-174, Berman, A., Karn, R. K., Epstein, M., 2005, “Kinetics of steam reforming of methane on Ru/Al 2 0 3 catalysts promoted with Mn oxides”, Applied catalysis A: General 282:73-83, and U.S. Pat. No. 5,431,855, the disclosures of which are hereby incorporated by reference. The permeable heat transfer wall 128 can also be constructed of silicon nitride or on a metallic wire mesh or other metallic, high surface area configuration and coated with a catalyst appropriate for the desired reaction. As used herein, in specifications or in claims, the term “silicon carbide” incorporates all compounds, washcoats or other coatings and materials containing any silicon carbide (SiC) or silicon carbide (SiSiC). As used herein, in specification or in claims, the term “alumina” incorporates all compounds, washcoats or other coatings and materials containing any alumina (Al 2 O 3 ). As used herein, in specifications or in claims, the term “silicon nitride” incorporates all compounds, washcoats or other coatings and materials containing any silicon nitride (Si 3 N 4 ).
[0069] The permeable heat transfer wall 128 may consist of several different materials in different axis symmetric zones as illustrated in FIG. 3 . The material in each zone is chosen according to the concentration of radiation expected to impinge thereon. Zone I, illustrated in FIG. 3 , may receive the lowest radiation flux and may therefore have the highest radiation absorptivity of the zones. Zone II illustrated in FIG. 3 , may receive the highest radiation flux and preferably have a low radiation absorptivity to prevent overheating of the permeable heat transfer wall 128 and/or overheating of window 126 as a consequence of a high temperature of the permeable heat transfer wall 128 . Preferably, the shape of zone II is highly concave to prevent reflected radiation from the surface 127 on 128 to exit the receiver through window 126 . Zone II would in such cases be closer to the window in the outer regions than in the inner/central regions,
[0070] The fluid from the fluid supply source 102 , supplied to vessel 120 via a supply conduit 121 , preferably is caused to impinge on surface 127 of the permeable heat transfer wall 128 . In a preferred embodiment, conduit 121 extends into the reactor 120 and into close proximity with surface 127 of the permeable heat transfer wall 128 . Alternatively, conduit 121 may not necessarily extend into the vessel 120 , and fluid from the fluid supply source 102 , supplied to vessel 120 via a supply conduit 121 may be caused to impinge on surface 127 of permeable heat transfer wall 128 by another suitable method.
[0071] In accordance with a preferred embodiment of the present invention, window 126 can be cooled, as by a flow of cooling fluid, such as pressurized air from a nozzle 130 impinging on the outside surface 132 of window 126 . The cooling action prevents excessive heating of the window from radiation absorption inside the window. The cooling of window 126 additionally prevents or reduces condensation on an inside surface 134 of window 126 and resultant reduction in the transparency thereof to incoming solar radiation and consequent excessive heating of the window 126 .
[0072] It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and sub-combinations of various feature of the invention and modifications thereof which may occur to persons skilled in the art upon reading the foregoing description and which are not in the prior art.
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A volumetric receiver vessel for heating a fluid with concentrated solar radiation which includes: an external housing having an aperture at the front end; an internal housing separating fluid entering the vessel from fluid exiting thereof; a window covering the aperture of the vessel, where the window closes and seals the aperture of said vessel against a non-metallic seal; and a radiation absorber, located inside the vessel and places to absorb radiation entering the vessel through said window on a radiation absorbing surface, where said surface include at least two zones with different radiation absorption coefficients.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S. divisional patent application Serial No. 10/163,814, filed Jun. 6, 2002, which claims benefit of U.S. Pat. No. 6,427,776, issued Aug. 6, 2002. Each of the aforementioned related patent applications is herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an apparatus for removing sand and other debris from a wellbore; more particularly, the invention relates to apparatus and methods for use in a wellbore utilizing a venturi.
[0004] 2. Background of the Related Art
[0005] In the production of oil and gas, sand breaks loose from oil producing formations and is carried into the wellbore with production fluid. As the production rate of oil increases, the formation sand which breaks loose and enters the wellbore also increases. Over time, the wellbore can become filled and clogged with sand making efficient production of the well increasingly difficult. In addition to sand from the formation, other debris including scale, metal shavings and perforation debris collects in the wellbore and interferes with production.
[0006] One method of removing debris from a wellbore involves the introduction of liquid which is circulated in the well. For example, liquid can be pumped down the wellbore through a pipe string and convey debris to the surface of the well upon return through an annulus formed between the pipe string and the wall of the wellbore. Nitrogen or some other gas can be added to the liquid to create a foam for increasing the debris carrying ability of the liquid. However, a relatively small amount of debris is actually conveyed to the well surface and removed in this manner because of the relatively large volume of space in a wellbore that must be filled with sand bearing liquid.
[0007] Another prior art method for removing debris from a well includes lowering a container into the well which is filled with debris and then removed. Typically, the container is sealed at the well surface and an atmospheric chamber formed therein. When the chamber is lowered into the well and opened, the pressure differential between the interior of the container and the wellbore causes the wellbore contents, like debris to be surged into the container. While this method of debris removal is effective, the amount of debris removed is strictly limited by the capacity of the container and in practice is typically not more than 85 % of the chamber volume. Additionally, the container must be continuously lowered into the well, filled due to pressure differential, raised from the well and emptied at the well surface.
[0008] More recently, a nozzle or other restriction has been utilized in the wellbore to increase circulation of a liquid and to cause, by low pressure, a suction thereunder to collect or “bail” debris. The use of a nozzle in a pressurized stream of fluid is well known in the art and operates according to the following principles: The nozzle causes pressurized liquid pumped from the surface of the well to assume a high velocity as it leaves the nozzle. The area proximate the nozzle experiences a drop in pressure. The high velocity fluid from the nozzle is diverted out of the tool and the low pressure area creates a vacuum in the tool below the nozzle, which can be used to create a suction and pull debris from a well along with fluid returning to the high velocity stream. By the use of a container, the debris can be separated from the flow of fluid, collected and later removed from the well. A prior art tool utilizing a nozzle and a diverter is illustrated in FIG. 1. The device 100 includes a nozzle portion 105 , a diverter portion 110 , a container 120 for captured debris and one way valve 125 to prevent debris from returning from the tool to the wellbore 130 . A filter is provided above the container but is designed to prevent the passage of particles larger than grains of sand. While the fluid pumped through the nozzle creates a low pressure and suction therebelow, this design is only marginally effective and the suction created in the tool results in only a partially filled container of debris. For example, experiments measuring the effectiveness of the prior art design of FIG. 1 have resulted in a measured suction of only 3-5″ of mercury.
[0009] Another apparatus for the removal of debris utilizes a venturi and is described in International Publication No. WO 99/22116 which is incorporated herein in its entirety by reference. The venturi utilizes a nozzle like the one illustrated in prior art FIG. 1. In additional to the nozzle, the venturi includes a throat portion and a diffuser portion to more effectively utilize the high velocity fluid to create a low pressure area and a suction therebelow. The apparatus of the 116 publication, like the device of FIG. 1 also includes a container for holding captured debris wherein the debris enters a flapper valve at the bottom of the container which fills with debris due to suction created by the venturi and is later removed from the well to be emptied at the well surface. While this arrangement is more effective than the one illustrated in FIG. 1, the mechanism is complex and expensive since each part of the device is specially fabricated and the parts are not interchangeable. Most importantly, the nozzle provided with the device is often too small to pass debris carried by the power fluid, clogging the nozzle and making the device useless. Additionally, the size of the container in the prior art devices is fixed limiting the flexibility of the tools for certain jobs requiring large capacity containers.
[0010] Aside from simply clearing debris to improve flow of production fluids, debris removal tools can be used to clear debris that has collected in a wellbore over the top of a downhole device, exposing the device and allowing its retrieval and return to the well surface. For example, a bridge plug may be placed in a wellbore in order to isolate one formation from another or a plug maybe placed in a string of tubular to block the flow of fluid therethough. Any of these downhole devices can become covered with debris as it migrates into the wellbore, preventing their access and removal. Removing the debris is typically done with a debris removal device in a first trip and then, in a separate trip, a device retrieval tool is run into the well. This process is costly in terms of time because of the separate trips required to complete the operation.
[0011] Debris removal is necessary in any well, whether live and pressurized or dead. In a live well, problems associated with the prior devices are magnified. Circulating fluid through a live well requires a manifold at the well surface to retain pressure within the wellbore. Use of an atmospheric chamber in a live well requires a pressure vessel or lubricator at the well surface large enough to house the atmospheric chambers.
[0012] There is a need for debris removal tool utilizing a high velocity fluid stream which effectively removes debris from a wellbore. There is a further need for a debris removal tool that can utilize interchangeable parts depending upon the quality of debris to be removed. There is a further need for a device retrieval tool which can also be used in a single trip to retrieve a downhole device as well as remove debris. There is yet a further need for a debris removal tool with an adjustable container formed of coiled tubing. There is a further need for a method of debris removal and device retrieval in a live well.
SUMMARY OF THE INVENTION
[0013] The present invention provides a simple debris removal apparatus for use in a wellbore. In one aspect of the invention a modular, interchangeable venturi is provided which can be retrofit into an existing debris bailer having a filter and a debris collection container. The venturi module replaces a simple and ineffective nozzle and results in a much more effective bailing apparatus. In another aspect of the invention, a venturi is utilized to create a negative pressure in a wellbore sufficient to actuate a retrieval tool for a downhole device. In yet another aspect of the invention, a combination tool is provided which can evacuate debris in a wellbore, thereby uncovering a downhole device which can then be removed in a single trip. In yet another aspect of the invention, a debris removal apparatus is provided with a method for utilizing the apparatus in a wellbore on coiled tubing. In yet another aspect of the invention a debris removal apparatus is provided which can be run on coiled tubing in a live well using a method of selective isolation and pressure bleed off. In yet another aspect, the. invention utilizes a section of coiled tubing for a debris container whereby the coiled tubing can be sized depending upon the amount of debris to be removed in the operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] 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.
[0015] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
[0016] [0016]FIG. 1 is a prior art debris removal tool having a simple nozzle to increase velocity of a fluid therein to create a suction in the tool therebelow.
[0017] [0017]FIG. 2 is a section view of the debris removal tool of the present invention showing a venturi in a diverter portion in the tool.
[0018] [0018]FIG. 3 is an enlarged view of the venturi portion of the tool showing the flow direction of fluid therethrough.
[0019] [0019]FIG. 4 is a section view showing one dimensional design of the venturi portion of the tool.
[0020] [0020]FIG. 5 is a section view showing one dimensional design of the venturi portion of the tool.
[0021] [0021]FIG. 6 is a section view showing one dimensional design of the venturi portion of the tool.
[0022] [0022]FIG. 7 is a section view showing one dimensional design of the venturi portion of the tool.
[0023] [0023]FIG. 8 is a section view of the present invention including a retrieval tool disposed at a lower end thereof.
[0024] [0024]FIG. 9 is a section view of the retrieval tool in an actuated, retracted position.
[0025] [0025]FIG. 10 is a section view of the retrieval tool in a un-actuated, extended position.
[0026] [0026]FIG. 11 depicts the debris removal tool of the present invention with coiled tubing disposed therein as a debris container.
[0027] [0027]FIG. 12 is the tool of FIG. 11 with a spoolable, double valve disposed within the length of coiled tubing and a retrieval tool disposed at the lower end of the tubing.
[0028] [0028]FIG. 13 is a section view showing a wellhead with a lubricator thereabove and a device retrieval tool disposed therein, the lubricator being installed on the wellhead.
[0029] [0029]FIG. 14 is a section view of the wellhead with the lubricator installed thereupon, the lubricator being pressurized to the pressure of the wellbore.
[0030] [0030]FIG. 15 is a section view of the wellhead with a blind ram opened, the retrieval tool having been lowered in the well and a double valve in the coiled tubing string in the lubricator.
[0031] [0031]FIG. 16 is a section view of the wellhead with a lower pipe ram in a closed position and the lubricator pressurized to atmospheric pressure.
[0032] [0032]FIG. 17 is a section view illustrating the wellhead with the lubricator having been lifted therefrom exposing the double valve and the coiled tubing severed thereabove.
[0033] [0033]FIG. 18 is a section view of the wellhead with debris removal tool inserted into the coiled tubing string and an access port installed therebelow.
[0034] [0034]FIG. 19 is a section view of the wellhead with the coiled tubing in the lubricator having been reattached to the coiled tubing in the wellhead, the upper pipe ram closed and the lubricator pressurized to the pressure of the wellbore.
[0035] [0035]FIG. 20 is a section view of a wellhead, the access port pressurized to the pressure of the wellbore and the upper and lower pipe rams opened.
[0036] [0036]FIG. 21 is a section view of the wellhead after the debris removal and device retrieval is completed, the debris removal tool raised into the lubricator and the double valve housed within the access port.
[0037] [0037]FIG. 22 is a section view of the wellhead wherein the upper and lower pipe rams have been closed and the access port has been pressurized to atmospheric pressure.
[0038] [0038]FIG. 23 is a section view of the wellhead showing a blind flange removed from the access port and the double valve adjusted to the closed position.
[0039] [0039]FIG. 24 is a section view of the wellhead showing the lubricator pressurized to atmospheric pressure and, thereafter, the upper pipe ram opened.
[0040] [0040]FIG. 25 is a section view of the wellhead showing the lubricator and debris removal tool removed from the wellhead, the coiled tubing severed above the double valve.
[0041] [0041]FIG. 26 is a section view of the wellhead showing the lubricator with the debris removal tool having been removed therefrom and a length of coiled tubing disposed within for connection to the coiled tubing extending from the wellhead therebelow.
[0042] [0042]FIG. 27 is a section view of the wellhead showing the lubricator pressurized to the pressure of the wellbore and thereafter, the lower pipe ram opened.
[0043] [0043]FIG. 28 is a section view of the wellhead showing the retrieval tool with the retrieved device lifted from the well and disposed within the lubricator.
[0044] [0044]FIG. 29 is a section view of the wellhead showing a blind ram in a closed position.
[0045] [0045]FIG. 30 is a section view of the wellhead showing the lubricator with the retrieval tool and retrieved device disposed therein and removed from the wellhead.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0046] [0046]FIG. 2 is a section view of a debris bailer tool 200 of the present invention. The tool includes an upper portion 205 , a venturi portion 210 , a diverter portion 215 , a debris screen or filter portion 220 and a debris container 225 including a flapper or ball valve 230 at a lower end thereof. The filter portion 220 is replaceable and is designed to separate debris as small as sand particles from return fluid passing from the container to the venturi portion. In the one embodiment for example, the filter removes particles as small as 8 microns. Depending upon well conditions and the needs of the operator, the screen can be sized for the debris expected to be encountered in the wellbore as well as the type of fluid in the wellbore. For example, some drilling muds will clog a fine screen, but will flow easily through a screen with larger openings therein. The tool 200 operates by the injection of fluid into the upper portion 205 where the fluid travels to the venturi portion 210 and the velocity of the fluid increases as it passes through the nozzle and is then diverted outside of the tool. In the preferred embodiment, the upper portion of the venturi is threaded allowing easy replacement of the venturi for different debris removal operations or a retro fitting of the venturi portion into a prior art tool like the one shown in FIG. 1. FIG. 3 is an enlarged view of the venturi portion of the tool. The venturi includes a nozzle 211 , throat 212 and a diffuser 213 .
[0047] According to the principals of a venturi device, high pressure power fluid passing through the nozzle has its potential energy (pressure energy) converted to kinetic energy in a jet of fluid at high velocity. The power fluid can be made up of a liquid like water or a foam or even a gas. Well fluid mixes with the power fluid in a constant area throat and momentum is transferred to the well fluid, causing an energy rise in the well fluid. As the mixed fluids exit the throat, they are still at the high velocity, and thus contain substantial kinetic energy. The fluids are slowed in an expanding area diffuser that converts the remaining kinetic energy to static pressure sufficient to lift fluids and with them debris, to a containment member in the tool. The arrows 214 in FIG. 3, illustrate the flow of fluid through and around the venturi. Return fluid is recirculated into the nozzle through ports 304 . In a well setting, the device creates a vacuum and fluid and debris are drawn into the container portion of the tool.
[0048] FIGS. 4 - 7 are section views of the venturi portion of the device and illustrate a variety of physical nozzle, throat return port and diffuser sizes to determine flow rates therethrough. In every example, the venturi 300 includes a nozzle 301 , a throat 302 and a diffuser 303 portion. If a throat size is selected such that the area of the nozzle is 60% of the throat area, a relatively high head, low flow rate will result. Adversely, if a throat is selected such that the area of the nozzle is only 20% of the throat area, more well fluid flow is possible. However, since the nozzle energy is being transferred to a large amount of production compared to the power fluid rate, lower heads will be developed. Design variables include the size of the nozzle and throat and the ratios of their flow areas, as well as component shapes, angles, lengths, spacing, finishes and materials. Through selection of appropriate flow areas and ratios, the venturi configuration can be optimized to match well conditions. Most importantly, a nozzle size can be selected to pass debris that may be present in the power fluid.
[0049] [0049]FIG. 8 is a section view of the present invention including a retrieval tool disposed at a lower end thereof. The retrieval tool 400 is installed at the end of the debris removal tool 200 and relies upon the same venturi forces for operation as are utilized by the debris removal tool 200 . Retrieval tools are well known in the art and are used to retrieve downhole devices like plugs, bridge plugs and packers that have been fixed temporarily in the wellbore but are designed for removal and are fitted with some means for attachment to a retrieval tool. The combined apparatus including the debris removal tool 200 and retrieval tool 400 are run into a well together in order to clear debris from the surface of a downhole device in the wellbore and then retrieve the device and bring it back to the surface of the well. The apparatus of the invention allows both of these operations to be completed in one time-saving trip into the wellbore.
[0050] [0050]FIGS. 9 and 10 are section views showing the retrieval tool 400 in its actuated (FIG. 9) and un-actuated (FIG. 10) positions. The tool 400 includes an outer body 405 , a slidable member 410 and a collet member 415 disposed between the outer body 405 and the slidable member 410 . The collet member 415 is equipped with fingers at a downhole end. Fingers 420 are designed to flex inward when the tool is actuated and to be prevented from inward flexing by the slidable member 410 when the tool is in the extended position. A biasing member 425 biases the slidable member in a normally extended, position as depicted in FIG. 10. In order to actuate the tool 400 and cause it to assume the retracted position shown in FIG. 9, a venturi device thereabove as depicted in FIG. 8 is operated creating a suction therebelow. The suction, in addition to gathering debris into the container as herein described, can also act upon a piston surface 430 formed at the downhole end of the retrieval tool, causing the inner member 410 to act against the biasing member 425 and the tool to assume a retracted position.
[0051] In operation, the retrieval tool 400 is run into the well along with the debris removal tool 200 . At a predetermined depth where debris is encountered, the debris removal tool 200 is operated and the debris removed from the wellbore and urged into the container 120 of the debris removal tool 200 . Throughout this operation, the retrieval tool 400 will be in an actuated, retracted position as shown in FIG. 9, its inner member urged upwards against the biasing member 425 by the suction force created in the debris removal tool 200 thereabove. After the debris has been contained and a downhole device 450 exposed for retrieval, the retrieval tool 400 , still in the actuated position, is inserted into a receiving member of the downhole device. Typically, the receiving member of the downhole device will include at least one profile 451 formed therein to interact with the fingers 420 of the retrieval tool 400 . The fingers 420 easily flex in order for the retrieval tool 400 to be inserted into the device 450 . Thereafter, the venturi device stops operating and the retrieval tool 400 returns to its normally extended position, preventing the fingers from flexing inward and locking the retrieval tool to the downhole device. The device 450 can then be removed by upward or rotational force or a combination thereof and raised to the top of the well along with the tools 200 , 400 .
[0052] In the embodiment described, the retrieval tool operates by communicating with a profile formed upon the inner surface of the downhole device. However, the tool could also operate with a downhole device having a profile formed on the outside thereof. In this case, the collet fingers would be prevented from inward flexing movement by the inner member.
[0053] Use of the debris removal tool of the present invention can be performed using a predetermined and measured length of coiled tubing as a debris container, whereby the tool can be easily and economically custom made for each debris removal job depending upon the amount of debris to be removed for a particular wellbore. FIG. 11 depicts a debris removal tool 500 with a length of coiled tubing 505 disposed within as a debris container. Rather than a permanent container like those depicted in FIGS. 1 & 2, the debris container in FIG. 11 is formed of coiled tubing that has been cut to length at the well surface and installed between the venturi portion 510 of the debris removal tool 500 and the filter 515 and one way valve 520 thereof.
[0054] In a preferred embodiment, a motor head 525 is inserted between the venturi portion and the coiled tubing thereabove, the motor head typically including connectors, double flapper check valves to prevent pressurized fluid from returning to the well surface and a hydraulic disconnect (not shown). The assembled apparatus can then be lowered into a wellbore to a predetermined depth proximate formation debris to be removed. The venturi apparatus is then operated, causing a suction and urging debris into the coiled tubing portion between the venturi 510 and the one way valve 520 .
[0055] [0055]FIG. 12 is a view of a debris removal tool 600 with a retrieval tool 610 disposed therebelow and a length of coiled tubing 615 disposed therebetween. Like the apparatus of FIG. 11, the coiled tubing 615 is used as a debris container and is measured and sized depending upon the amount of debris to be removed. In addition, a spoolable, double valve 620 is inserted in the coiled tubing string. The purpose of the spoolable, double valve is to facilitate the isolation of areas above and below the valve when debris and/or a downhole device is removed from a live well as described below. Because the double valve is spoolable, it can be wound on and off of a reel without being removed from a string of coiled tubing. In the preferred embodiment, the valves making up the double valve are ball valves. However, any type valve could be used so long as it is tolerant of stresses applied during reeling and unreeling with coiled tubing.
[0056] [0056]FIG. 13 is a section view showing a wellhead 700 with a blind ram 705 in a closed position and a lubricator 715 disposed thereabove with a retrieval tool 720 at the end of a coiled tubing string 725 disposed therein. The lubricator 715 is a pressure vessel which can be pressurized to the pressure of the wellbore and placed in fluid communication with the wellbore. At an upper end of the lubricator 715 , a stripper 730 allows coiled tubing to move in and out of the lubricator, maintaining a pressurized seal therewith. Valves 735 , 740 are provided at an upper end of the lubricator for pressurizing and bleeding pressure. FIG. 14 is a section view showing the wellhead 700 with the lubricator 715 attached thereto. The lubricator 715 is pressurized via valve 740 to wellbore pressure by an external source of pressure. In the preferred embodiment, the retrieval tool 720 within the lubricator 715 includes a meltable plug (not shown) disposed in the end thereof. The plug is made of a substance which, at ambient temperature is a solid that seals the interior of the tool to external pressure. The plug is designed to melt and disintegrate at temperatures found in the wellbore where the debris removal will take place.
[0057] [0057]FIG. 15 is a section view showing the wellbore opened and the retrieval tool lowered into the wellbore a predetermined distance. Double valve 620 , inserted in the string of coiled tubing 615 , is at a location within the lubricator 715 . FIG. 16 is a section view of the apparatus with a lower pipe ram 745 in the closed position and thereafter, the pressure in the lubricator bled off via valve 735 .
[0058] [0058]FIG. 17 is a section view of the wellhead 700 with the lubricator 715 and raised thereabove. The coiled tubing string 615 has been severed above the double valve 620 . FIG. 18 illustrates the assembly with the debris removal tool 510 and motor head 525 disposed within the lubricator 715 and an additional access port 750 and upper ram 755 added to the lubricator. FIG. 19 is a section view wherein the lubricator 715 , upper pipe ram 755 and access port 750 have been attached to the wellhead 700 with the lower pipe ram 745 closed. The lubricator 715 is pressurized via valve 740 to the pressure of the wellbore. FIG. 20 is a section view wherein the lower pipe ram 745 is open and the debris removal tool is lowered into the wellbore sufficient distance to place the retrieval tool therebelow in the area of the debris to be removed.
[0059] In the preferred embodiment, the retrieval tool is lowered into the well with a length of coiled tubing there behind sufficient and volume to house the debris which will be removed from the wellbore. After a sufficient amount of coiled tubing has been lowered into the well behind the retrieval tool, the venturi apparatus with its double safety valve is installed in the coiled tubing. As the retrieval tool reaches that location in the wellbore where it will be removed, the temperature present in the wellbore causes the plug in the end of the retrieval tool to melt by exposing the coiled tubing section to wellbore pressure and permitting communication between the venturi apparatus and the debris containing wellbore.
[0060] [0060]FIG. 21 depicts the wellhead assembly after the debris removal and device retrieval has been completed and the debris removal tool 510 has been raised out of the wellbore and is housed again in the lubricator 715 . Visible specifically in FIG. 21 is the double valve 620 , still in its opened position and raised to a location where it is accessible through the access port 750 . FIG. 22 is a section view depicting the upper pipe ram 755 between the access port 750 and the lubricator 715 in a closed position and the lower pipe ram 745 between the access port 750 and the wellhead 700 also in a closed position in order to isolate the access port 750 . As depicted in the figure, with the access port 750 isolated above and below, pressure is bled therefrom.
[0061] [0061]FIG. 23 is a section view depicting an access plate 751 removed from the access port 750 and the double valve 620 manipulated to a closed position. FIG. 24 is a section view of showing the pressure bled from the lubricator 715 via valve 735 . FIG. 25 depicts the lubricator 715 and access port 750 having been removed from the wellhead 700 , exposing the double valve 620 , the coiled tubing 615 thereabove having been severed.
[0062] [0062]FIG. 26 depicts the lubricator 715 with the debris removal tool 510 removed therefrom, leaving only a string of coiled tubing 615 in the lubricator 715 . As depicted in the figure, the coiled tubing string in the lubricator can now be reconnected to the coiled tubing string extending from the double valve 620 , which remains in the closed position. FIG. 27 is a section view depicting the lubricator 715 having been reconnected to the wellhead 700 and pressurized to wellbore pressure via valve 740 . Thereafter, the lower pipe ram 745 is opened and, as illustrated by the directional arrow, the coiled tubing string 615 is retracted from the wellbore.
[0063] [0063]FIG. 28 is a section view wherein the retrieval tool 610 and downhole device 611 has been lifted from the wellbore and is housed within the lubricator 715 . FIG. 29 is a section view wherein the blind ram 705 has been closed and, thereafter, the pressure within the lubricator 715 is bled via valve 735 . FIG. 30 is a section view wherein the lubricator 715 , the retrieval tool 610 and downhole device 611 have been removed from the wellhead 700 and the debris removal and tool retrieval procedure is completed, leaving the wellhead 700 with the blind ram 705 in the closed position.
[0064] As described in the forgoing, the invention solves problems associated with prior art sand removal tools and provides an efficient, flexible means of removing debris or retrieving a downhole device from a live or dead well. The design of the tool is so efficient that tests have demonstrated a suction created in the tool measured at 28″ of mercury, compared with a measure of as little as 3-5″ of mercury using a prior art device like the one shown in FIG. 1.
[0065] While 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 that follow.
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The present invention provides a simple debris removal apparatus for use in a wellbore. In one aspect of the invention a modular, interchangeable venturi is provided which can be retrofit into an existing debris bailer having a filter and a debris collection container. In another aspect of the invention, a venturi is utilized to create a negative pressure in a wellbore sufficient to actuate a retrieval tool for a downhole device. In yet another aspect of the invention, a combination tool is provided which can evacuate debris in a wellbore, thereby uncovering a downhole device which can then be removed in a single trip. In yet another aspect of the invention, a debris removal apparatus is provided with a method for utilizing the apparatus in a wellbore on coiled tubing.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a regolith container for use with a structure on an extraterrestrial mass. The filled container provides a measure of protection for the structure against radiation and space debris. The structure can be a solid, semi-solid, or expandable structure.
2. Description of Related Art
Environments on other planets and moons in our solar system are hostile to unaided human habitation. There can be caustic chemical environments and, in some instances, temperatures can vary between more than one hundred degrees centigrade to below one hundred degrees centigrade in relatively short periods of time. Furthermore, many extraterrestrial masses have little or no atmosphere. This lack of atmosphere has serious implications on structures designed to establish a human presence on these other worlds.
Little or no atmosphere means that various forms of solar radiation reach the surface of these worlds without any attenuation. Subatomic particles and electromagnetic radiation across the spectrum bombard the surface of these worlds unimpeded. This radiation can degrade and decompose the materials used to construct human habitat structures.
The lack of any significant atmosphere also permits space debris to strike the surface of these worlds. The size of such debris and the potential lethality can vary greatly. With the aid of the gravity generated by these worlds, and the initial velocity of the debris in space, surface impacts can impart tremendous amounts of energy.
While technology can potentially provide the answer with the use of debris and radiation shielding, this is not the optimum solution. The cost of launching debris shields into orbit and then landing the shields on an extraterrestrial mass can be staggering.
One proposed solution is the use of the naturally occurring regolith of the mass to cover the habitat structure as identified in U.S. Pat. No. 5,058,330 to Chow. The regolith provides a layer of protection to absorb radiation and disperse the energy of debris impacts incident upon the structures.
While the use of regolith appears to be a cost effective solution to the alternative of launching debris shields, the movement of the regolith is an issue that can undermine the use of regolith as an answer to the problem. To move the regolith may require specialized heavy equipment such as bulldozers. The weight of such equipment drives up the launch cost. Furthermore, the use of such equipment can create dust in the atmosphere that may interfere with other operations on the surface of the object.
What is needed is a way to utilize regolith as a shield for extraterrestrial habitats without adversely impacting the launch cost and without interfering with other surface activities.
BRIEF SUMMARY OF THE INVENTION
A regolith container for use with a structure on an extraterrestrial mass is claimed. The regolith container has a body having a first end and a second end, the second end disposed opposite the first end and the second end being closed. The body is hollow and substantially flexible. The first end is adapted to receive regolith from an extraterrestrial mass and the regolith substantially filling the hollow body. The first end adapted to substantially close when the body is substantially filled with regolith. When the container is filled with the regolith, the container is adapted to cover a portion of a structure disposed on the extraterrestrial mass thereby providing a measure of protection for the structure.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 is a partial side view of the regolith container;
FIG. 2 is a partial side view of the regolith container including a funnel;
FIG. 3 is a side view of the regolith container being filled with regolith;
FIG. 4 is a perspective view of a twist in the regolith container;
FIG. 5 is a perspective view of a regolith container and a tie;
FIG. 6 is a perspective view of the regolith container tied at one end; and
FIG. 7 is an end view of a spacecraft covered by a regolith container;
FIG. 8 is a perspective view of a spacecraft partially covered by regolith containers.
DETAILED DESCRIPTION
Persons of ordinary skill in the art will realize that the following description is illustrative only and not in any way limiting. Other modifications and improvements will readily suggest themselves to such skilled persons having the benefit of this disclosure. In the following description, like reference numerals refer to like elements throughout.
Referring now to FIG. 1 , a side view of a regolith container 14 is disclosed. The container 14 has a first end 16 that is open and a second end 18 that is substantially closed. The container has a length 10 and a diameter 12 . In the preferred embodiment, the length 10 can extend to sixty yards and the diameter of the opening 16 is approximately 14 inches. In the preferred embodiment, the container 14 is substantially cylindrical. However, alternative shapes and geometries are also possible as dictated by the specific requirements of each case. Also, the container 14 can be filled by any number of methods known within the art without modification of the container 14 . The container 14 can be constructed from materials that are malleable to a degree and resistant to radiation and penetration by debris. It will be appreciated by those of skill in the art that such materials can be chosed based upon the specific environment of the extraterrestrial mass. Furthermore, the dimensions can be varied to accommodate a variety of situations.
FIG. 2 illustrates a funnel 20 attached to the open end 16 of the regolith container 14 . the funnel has a wider mouth 22 than the opening 12 of the container 14 . Further, there are attachment points 24 on the funnel 20 . the funnel 20 directs regolith into the container 14 .
Turning now to FIG. 3 , there are cords 26 connected to the attachment points 24 of the funnel 20 . the funnel 20 and container 14 are in contact with the regolith 27 of an extraterrestrial mass 28 . As illustrated in the cutaway view 29 of the container 14 , the regolith 27 fills the container 14 . The funnel and container can be drawn over the landscape by various means. For example, on worlds where the gravity is lower than on Earth, a person in an environmental suit could draw the funnel and container. In other situations, surface transportation, such as a lunar rover, could be used that is not exclusive to the task of filling the container. The cords 26 can also be cables, chains, or other such materials.
FIG. 4 illustrates how a segment 31 of the container 14 can be obtained by twising 28 the container 14 in a particular direction of rotation 30 . This action compartmentalizes the container. In this way, should an impact penetrate a single segment 31 then the leakage of the regolith would be confined and not extend to the entire container 14 .
As shown in FIG. 5 , a segment can be created by other methods including the use of ties 32 . The tie 32 substantially confines regolith in the segment. Again, this compartmentalizes the container.
In FIG. 6 , the container 14 is substantially filled with regolith at which point the funnel 20 is removed and the open end 16 of the container 14 is sealed off. This can be accomplished by any number of ways including, but not limited to, the use of ties, heat sealing, and knotting.
Addressing FIG. 7 , the container 14 is placed over a space structure 36 on an extraterrestrial mass 28 . In this figure, there are a number of segments 31 identified.
FIG. 8 illustrates how a plurality of containers 14 are used to cover a spacecraft 36 .
While embodiments and applications of this disclosure have been shown and described, it would be apparent to those skilled in the art that many more modifications and improvements than mentioned above are possible without departing from the inventive concepts herein. The disclosure, therefore, is not to be restricted except in the spirit of the appended claims.
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A regolith container for use with regolith on an extraterrestrial mass is disclosed. The filled container covers a portion of a spacecraft to provide the spacecraft with a measure of protection against space debris and radiation. The container can be compartmentalized to reduce the loss of regolith should from the container if a single compartment is penetrated.
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